COMSOL Multiphysics Release Notes© 1998–2020 COMSOL
Protected by patents listed on www.comsol.com/patents, and U.S. Patents 7,519,518; 7,596,474;
7,623,991; 8,219,373; 8,457,932; 9,098,106; 9,146,652; 9,323,503; 9,372,673; 9,454,625; 10,019,544;
10,650,177; and 10,776,541. Patents pending.
This Documentation and the Programs described herein are furnished under the COMSOL Software License
Agreement (www.comsol.com/comsol-license-agreement) and may be used or copied only under the termsof the license agreement.
Support for implementation of the ODB++ Format was provided by Mentor Graphics Corporation pursuant
to the ODB++ Solutions Development Partnership General Terms and Conditions. ODB++ is a trademark
of Mentor Graphics Corporation.
COMSOL, the COMSOL logo, COMSOL Multiphysics, COMSOL Desktop, COMSOL Compiler,
COMSOL Server, and LiveLink are either registered trademarks or trademarks of COMSOL AB. All othertrademarks are the property of their respective owners, and COMSOL AB and its subsidiaries and products
are not affiliated with, endorsed by, sponsored by, or supported by those trademark owners. For a list of suchtrademark owners, see www.comsol.com/trademarks.
Version: COMSOL 5.6

Contact Information
Visit the Contact COMSOL page at www.comsol.com/contact to submit generalinquiries, contact Technical Support, or search for an address and phone number. You canalso visit the Worldwide Sales Offices page at www.comsol.com/contact/offices foraddress and contact information.
If you need to contact Support, an online request form is located at the COMSOL Accesspage at www.comsol.com/support/case. Other useful links include:• Support Center: www.comsol.com/support• Product Download: www.comsol.com/product-download• Product Updates: www.comsol.com/support/updates• COMSOL Blog: www.comsol.com/blogs• Discussion Forum: www.comsol.com/community• Events: www.comsol.com/events• COMSOL Video Gallery: www.comsol.com/video• Support Knowledge Base: www.comsol.com/support/knowledgebase
Part number: CM010001

C o n t e n t
Chapter 1: Release Notes
New Products
Battery Design Module

8. . . . . . . . . . . . . . . . . . . .

8Fuel Cell & Electrolyzer Module . . . . . . . . . . . . . . . . .

8Liquid & Gas Properties Module . . . . . . . . . . . . . . . . .

8Polymer Flow Module . . . . . . . . . . . . . . . . . . . . .

8LiveLink™ for Simulink® . . . . . . . . . . . . . . . . . 9

COMSOL Multiphysics

10

General New Functionality . . . . . . . . . . . . . . . . . . . 10
New Functionality in the Application Builder . . . . . . . . . . . . 10
New Functionality in COMSOL Compiler™ . . . . . . . . . . . . 13
New Functionality in COMSOL Server™. . . . . . . . . . . . . . 14
New and Improved General Functionality in COMSOL Multiphysics . . . 14
New Geometry and Mesh Functionality . . . . . . . . . . . . . . 17
New Functionality in the Physics Interfaces . . . . . . . . . . . . . 19
New and Updated Operators, Functions, and Definitions. . . . . . . 20

New Functionality in Studies and Solvers . . . . . . . . . . . . . . 22
New and Improved Results and Visualization Functionality . . . . . . . 25®
New Java API Methods . . . . . . . . . . . . . . . . . . . . 28
General Backward Compatibility Considerations . . . . . . . . . . . 31
Backward Compatibility with Version 5.5. . . . . . . . . . . . . . 31
Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 31
Backward Compatibility with Version 5.3a . . . . . . . . . . . . . 32
Backward Compatibility with Version 5.3. . . . . . . . . . . . . . 33
AC/DC Module

36

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 36
New and Updated Models in Version 5.6 . . . . . . . . . . . . . . 37
Backward Compatibility with Version 5.4 and Earlier . . . . . . . . . 38
Acoustics Module

39

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 39
New and Updated Model Examples in 5.6 . . . . . . . . . . . . . 45
Backward Compatibility with Version 5.5. . . . . . . . . . . . . . 45
Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 46
Backward Compatibility with Version 5.3a . . . . . . . . . . . . . 46
Backward Compatibility with Version 5.3. . . . . . . . . . . . . . 46
Battery Design Module

47

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 47
New and Updated Applications and Models in Version 5.6 . . . . . . . 51
Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 51
CAD Import Module, Design Module, and LiveLink™ Products for CAD 52
New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 52
New Functionality in the Design Module in Version 5.6 . . . . . . . . 52
New Functionality in LiveLink™ for AutoCAD® in Version 5.6 . . . . . 53
New Functionality in LiveLink™ for Inventor® in Version 5.6 . . . . . . 54

CONTENTS | 3

New Functionality in LiveLink™ for PTC® Creo® Parametric™ in Version 5.6 54
New Functionality in LiveLink™ for Revit® in Version 5.6 . . . . . . . 54®
New Functionality in LiveLink™ for Solid Edge in Version 5.6 . . . . . 54®
New Functionality in LiveLink™ for SOLIDWORKS in Version 5.6 . . . 55
Backward Compatibility with Previous Versions . . . . . . . . . . . 55
CFD Module

56

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 56
New Models in Version 5.6 . . . . . . . . . . . . . . . . . . . 57
Backward Compatibility with Version 5.5 and Earlier . . . . . . . . . 58
Backward Compatibility with Version 5.4 and Earlier . . . . . . . . . 58
Backward Compatibility with Version 5.3a . . . . . . . . . . . . . 59
Chemical Reaction Engineering Module

60

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 60
New Applications in Version 5.6 . . . . . . . . . . . . . . . . . 64
Updated Applications in Version 5.6. . . . . . . . . . . . . . . 65

Backward Compatibility with Version 5.4 and Earlier . . . . . . . . . 66
Backward Compatibility with Version 5.3a and Earlier . . . . . . . . . 67
Composite Materials Module

68

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 68
New Models in Version 5.6 . . . . . . . . . . . . . . . . . . . 71
Corrosion Module

73

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 73
New and Updated Models in Version 5.6 . . . . . . . . . . . . . . 76
Backward Compatibility with 5.4 . . . . . . . . . . . . . . . . . 77
ECAD Import Module

78

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 78
Backward Compatibility with Version 5.3a . . . . . . . . . . . . . 78
Electrochemistry Module

79

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 79
Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 82
Electrodeposition Module

83

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 83
New and Updated Models in Version 5.6 . . . . . . . . . . . . . . 86
Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 87
Fatigue Module

88

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 88
Geomechanics Module

89

New Functionality in Version 5.6 . . . . . . . . . . . . . . . . . 89
New Models in Version 5.6 . . . . . . . . . . . . . . . . . . . 90
Heat Transfer Module91

New and Improved Functionality in Version 5.6 . . . . . . . . . . . 91
New Applications in Version 5.6 . . . . . . . . . . . . . . . . . 96
Updated Applications in Version 5.6. . . . . . . . . . . . . . . 97

Backward Compatibility with Version 5.5. . . . . . . . . . . . . . 97

4 | CONTENTS

Backward Compatibility with Version 5.4. . . . . . . . . . . . . . 98
Backward Compatibility with Version 5.3a . . . . . . . . . . . . . 99
Backward Compatibility with Version 5.3. . . . . . . . . . . . .

101

MEMS Module

103

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

103

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

106

Metal Processing Module

109

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

109

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

110

Microfluidics Module

111

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

111

Backward Compatibility with Version 5.5. . . . . . . . . . . . .

111

Backward Compatibility with Version 5.3a . . . . . . . . . . . .

112

Mixer Module

113

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

113

Multibody Dynamics Module

114

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

114

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

118

Updated Models and Apps in Version 5.6. . . . . . . . . . . . .

119

Nonlinear Structural Materials Module

120

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

120

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

122

Optimization Module

124

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

124

New and Updated Models and Apps in Version 5.6 . . . . . . . . .

125

Backward Compatibility with Version 5.4. . . . . . . . . . . . .

126

Particle Tracing Module

127

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

127

New and Updated Applications in Version 5.6 . . . . . . . . . . .

130

Backward Compatibility with Version 5.5. . . . . . . . . . . . .

130

Backward Compatibility with Version 5.4. . . . . . . . . . . . .

130

Backward Compatibility with Version 5.3 and Earlier . . . . . . . .

131

Pipe Flow Module

132

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

132

Updated Model in Version 5.6 . . . . . . . . . . . . . . . . .

132

Backward Compatibility with Version 5.3. . . . . . . . . . . . .

132

Plasma Module

133

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

133

Backward Compatibility with Version 5.5 and Earlier . . . . . . . .

133

Porous Media Flow Module

134

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

134

New Models and Apps in Version 5.6 . . . . . . . . . . . . . .

137

CONTENTS | 5

Ray Optics Module

138

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

138

New Applications in Version 5.6 . . . . . . . . . . . . . . . .

140

Important Fixes in Version 5.6 . . . . . . . . . . . . . . . . .

141

Backward Compatibility with Version 5.5. . . . . . . . . . . . .

141

Backward Compatibility with Version 5.4. . . . . . . . . . . . .

142

Backward Compatibility with Version 5.3 and Earlier . . . . . . . .

142

RF Module

144

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

144

New and Updated Models in Version 5.6 . . . . . . . . . . . . .

145

Rotordynamics Module

147

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

147

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

149

Semiconductor Module

151

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

151

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

152

Structural Mechanics Module154

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

154

New and Updated Models in Version 5.6 . . . . . . . . . . . . .

162

Subsurface Flow Module

165

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

165

New Models in Version 5.6 . . . . . . . . . . . . . . . . . .

166

Wave Optics Module

168

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

168

New and Updated Models in Version 5.6 . . . . . . . . . . . . .

169

Material Library172

New and Updated Material Data in Version 5.6 . . . . . . . . . .

172®

LiveLink™ for Excel

173

New Functionality in Version 5.6 . . . . . . . . . . . . . . . .

173

®

174

LiveLink™ for MATLABNew Functionality in Version 5.6 . . . . . . . . . . . . . . . .

174

Backward Compatibility with Version 5.4. . . . . . . . . . . . .

175

The COMSOL API for Use with Java®

176

COMSOL 5.6 API Changes . . . . . . . . . . . . . . . . . .

176

COMSOL 5.4 API Changes . . . . . . . . . . . . . . . . . .

176

COMSOL 5.3a API Changes. . . . . . . . . . . . . . . . . .

177

COMSOL 5.3 API Changes . . . . . . . . . . . . . . . . . .

177

COMSOL 5.2a API Changes. . . . . . . . . . . . . . . . . .

178

COMSOL 5.1 API Changes . . . . . . . . . . . . . . . . . .

179

COMSOL 5.0 API Changes . . . . . . . . . . . . . . . . . .

181

6 | CONTENTS

1

Release Notes
COMSOL Multiphysics® version 5.6 includes the new LiveLink™ for Simulink®,
Polymer Flow Module, Liquid & Gas Properties Module, Battery Design Module,and Fuel Cell & Electrolyzer Module; extended and improved versions of the
Application Builder, COMSOL Compiler™, COMSOL Server™, and COMSOLMultiphysics®; as well as updates and improvements for all COMSOLMultiphysics® add-on products. These Release Notes provide information
regarding new functionality in version 5.6 for all COMSOL® software products.

7

New Products
The previous Batteries & Fuel Cells Module has been replaced by the Battery Design
Module. In addition, the 5.6 release adds a dedicated Fuel Cell & Electrolyzer Moduleand the following new products: the Polymer Flow Module, Liquid & Gas Properties
Module, and LiveLink™ for Simulink®.

Battery Design Module
The Battery Design Module replaces the previous Batteries & Fuel Cells Module andcontains functionality for design and analysis of batteries.

Fuel Cell & Electrolyzer Module
The Fuel Cell & Electrolyzer Module models the underlying electrochemical behavior
in electrodes and electrolytes of fuel cells and electrolyzers. With this module, you caninvestigate performance for different operating conditions and designs and simulatecharacteristics such as the transport of ions, current conduction, two-phase gas-liquid
fluid flow, heat transfer, and the nature and driving forces of electrochemical reactionsat planar electrodes and in porous gas diffusion electrodes.

Liquid & Gas Properties Module
The Liquid & Gas Properties Module provides features for modeling ofthermodynamic properties of liquids and gases. Use this module to compute thedensity, viscosity, thermal conductivity, heat capacity and other properties of mixtures
as functions of pressure and temperature. These properties can be used for modelingand simulation in CFD, heat transfer, and acoustics.

Polymer Flow Module
The Polymer Flow Module includes functionality for modeling of fluids withviscoelastic, thixotropic, shear thickening, or shear thinning properties. You can also
account for the properties of the fluids as a function of temperature and composition
to model cure and polymerization. In combination with other modules in COMSOLMultiphysics, you can also model fully coupled and time-dependent fluid-structureinteractions.

8 |CHAPTER 1: RELEASE NOTESLiveLink™ for Simulink®
LiveLink™ for Simulink® is a new product that enables two-way communication
between COMSOL Multiphysics and Simulink.
The most prominent feature is the ability to perform cosimulation. You can take any
COMSOL Multiphysics model, define a few inputs and outputs, and then simulate the
COMSOL Multiphysics model using the new COMSOL Cosimulation block in
Simulink. When the simulation runs, Simulink is in charge of the overall simulation
scheme, and Simulink and COMSOL Multiphysics exchange data at so-called
communication points. COMSOL Multiphysics then perform its own time stepping in
between these communication points.
In order to make it possible to perform control design and to speed up simulation, you
can extract state-space models based on a COMSOL Multiphysics model. Using model
reduction, it is possible to reduce the number of states from millions to just a few andstill be able to capture the dynamics of the input/output system.

NEW PRODUCTS|

9COMSOL Multiphysics
General New Functionality
PASSCODE INSTALLATIONS

It is now possible to use a passcode for installation of the COMSOL software when the
installation is not a trial.
COMPARING TWO SELECTED NODESWhen you select two nodes with settings in the Model Builder tree or Application
Builder tree, right-click and choose Compare Selected Nodes to compare the contentsof the two nodes.
MPI I/O MODE

The -mpii cluster command is available for Windows ® and Linux® to set the MPI
I/O mode.

New Functionality in the Application Builder
GENERAL IMPROVEMENTS

Generating Numerical Evaluation Code
When a Derived Values feature node or an Evaluation Group node is selected in the Model
Builder, the following four options for generating numeric evaluation code are alsoavailable:• Evaluate real scalar to evaluate a real scalar value.
• Evaluate real matrix to evaluate the values of a real matrix.
• Evaluate imaginary scalar to evaluate an imaginary scalar value.
• Evaluate imaginary matrix to evaluate the value of an imaginary matrix.
The corresponding functionality is available in the Editor Tools window.

Testing Apps in Microsoft Edge ®
Under the Test in Web Browser menu button on the ribbon in the Application Builder,
Microsoft Edge® has been added as a browser used to test apps.

10 |CHAPTER 1: RELEASE NOTESColor Themes
The desktop color theme in apps is determined by the new Themes node, where you
can specify color themes for the app and for image export. For example, you can makean app using the dark theme but still export images in the default theme.
IMPROVEMENTS TO THE FORM EDITOR

Layout Templates
The New Form wizard now includes a number of layout templates for forms withcombinations of ribbons or toolbars, sections, tabs, and graphics as well as layout
templates suited for displaying the app on tablets and smartphones. You can also define
and add custom layout templates to the wizard.

Knob Form Object
A new Knob form object is available as a way for app users to adjust some value using
a knob as an alternative to a slider.

Local Forms
You can now add local forms that can be used by a parent global form (that is, Formnodes that appear directly under the Forms node). Local forms have a limited scopethat consists of the parent global form and its subnodes (for example, local declarations
defined by the parent global form).

Editor Previews
The Preview window in the Application Builder no longer has a cross for closing it, and
the Preview button has been removed from the ribbon. Instead, there is a setting on
the Application Builder page in the Preferences dialog box, which you can use to control
the preview’s presence.

Card Stack Size Adjustments
A card stack can now adjust its size to the selected card using the Adjust size to selectedcard setting. When selected, the card stack will adjust its size to the currently selected

card.

Additional Positions for the About Link
The About link in an app can now be placed in the lower-left corner.

Showing and Hiding Column Headers in Results Table Form Objects
There is now an option to show or hide the column headers of Results Table form
objects.

COMSOL MULTIPHYSICS|

11

Selected Icon Settings For Toggle Buttons and Toggle Items
Toggle Items, used for Toggle Button and Toolbar form objects, now have a Selected
Icon setting. The Selected Icon is displayed when the toggle is in the selected state.

Unit Support for Data Display Form Objects
The Data Display form object can now evaluate expressions using an arbitrary unit.
The Unit setting is located in the Number Format section of the Data Display node’s
Settings window.

Improvements to the Selection Input Form Objects
The Selection Input form object now includes support for On data change events.
The event handling method is triggered when the selection that the selection input isconnected to changes. If you use Create local method for the On data change event,
you get a method with an integer array argument. The method is called with the newentities of the selection.
Other improvements to the Selection Input form object:• It is now possible to click the Activate Selection button to deactivate the selection.
When doing so, the associated Graphics form object (in apps) shows the geometry
without the selection. In Settings forms, the Graphics form object behaves like itdoes for any other Settings window when deactivating a selection widget.
• The Selection Input form object now has an active property, which can be set frommethod code to change the active state of the selection.
• The is a new On activated event, which is triggered when a selection input isactivated.

Text Alignment for Array Input Form Objects
The Array Input form object now includes a setting for specifying the text alignment.
IMPROVEMENTS AND CHANGES FOR THE APPLICATION LANGUAGE

See also the Application Programming Guide for a complete overview of theapplication language for programming methods in the Application Builder for use inapplications, models, and add-ins.

Running the Zoom to Selection CommandA new utility method for running the Zoom to Selection command has been added.
Example syntax:
Zoom to selection in the main Graphics window in the Model Builder:zoomToSelection();

12 |CHAPTER 1: RELEASE NOTES

Zoom to selection in the given graphics form object:zoomToSelection("form1/graphics1"); or
zoomToSelection(app.form("form1").formObject("graphics1"));

Commands for Writing Byte Order Marks
New variants of the writeFile and writeCSVFile commands have been added. The
new variants write an optional byte order mark (BOM) to the files. If the append flagis true, the BOM flag is ignored. Example syntax:
Write a double matrix to a CSV file with byte order mark:writeCSVFile("C:\\Temp\\file.csv", new double[][]{newdouble[]{1,2,3}}, false, true);

Write a string matrix to a CSV file with byte order mark:writeCSVFile("C:\\Temp\\file.csv", new String[][]{newString[]{"1","2","3"}}, false, true);

Write a double matrix to file with byte order mark:writeFile("C:\\Temp\\file.txt", new double[][]{newdouble[]{1,2,3}}, false, true);

Write a string to file with byte order mark:writeFile("C:\\Temp\\file.txt", "text", false, true);

Write a string matrix to file with byte order mark:writeFile("C:\\Temp\\file.txt", new String[][]{newString[]{"1","2","3"}}, false, true);

New Functionality in COMSOL Compiler™
COMSOL RUNTIME INFORMATION PAGE

When running a compiled application for the first time, the COMSOL Runtime will
be installed on your computer in order to run it. To make it easier to get information
about what COMSOL Runtime is, a new COMSOL Runtime Information button is now
displayed in the bottom-left corner of the installer. The button directs you tohttps://www.comsol.com/runtime-information.

COMSOL MULTIPHYSICS|

13

New Functionality in COMSOL Server™
DARK THEME FOR APPSCOMSOL Server fully supports apps using the new dark theme, both in COMSOLClient and when using a web browser.
CUSTOM BACKGROUND COLORSThe form background now fills the whole viewport when running apps, allowing foruse of custom background colors.
APPLICATION USAGE LOG

A log of all completed application sessions is now available under
Administration>Application Usage. The information can be exported to a text file or
spreadsheet.

New and Improved General Functionality in COMSOL Multiphysics
COLOR THEMESThe following color themes are now available for the COMSOL Desktop: default,
light, and dark. The default theme corresponds to the color theme in earlier versionsof COMSOL Multiphysics. The color themes are also available for image export andin plot groups.
You can specify color theme preferences for the desktop, graphics, and image export
on the Color Themes page in the Preferences dialog box.
User-defined theme files now include a section % Palette, where you can definecolors to use in later sections. For example:% Palette
MyColor=100 120 130% Graphics colors
key=MyColor

For the API, the following methods are available:• model.colorTheme(<theme>) sets the color theme to be used in graphics.
automatic indicates that the theme specified in the preferences will be used. The
other possible theme values are the names of the themes in the data/color folder
in the COMSOL installation folder.

14 |CHAPTER 1: RELEASE NOTES• model.colorTheme() returns the current theme.
• model.imageColorTheme(<theme>) sets the color theme for image export.
• model.imageColorTheme() returns the current image export color theme.
The color themes that in earlier versions were called Dark and Light are now called
DarkSelection and LightSelection.
INTERACTIVE CLIPPING OF 3D GEOMETRIESTo make it easier to select edges, boundaries, and domains that are located inside asurrounding object, you can now use interactive clipping. Add Clip Plane, Clip Box, Clip
Cylinder, and Clip Sphere clipping features to select what parts of a geometry are shown.
The interactive clipping functionality works throughout the Model Builder and isavailable from a menu button in the Graphics toolbar. When you click the toolbar
button, by default, a Clip Plane node is added to the View node with settings that you
can adjust in a Settings window or interactively in the Graphics window. Multiple clip
planes can be added and used concurrently.
ENVIRONMENT MAPS

For 3D graphics, you can now include environment mapping by choosing from twoenvironment maps in a 3D View node’s Settings window: Indoor and Outdoor. By
default, reflections of the environment map appear in the model geometry. You canalso select a Skybox check box to show the environment map as a background image
using a so-called skybox.
GRAPHICS WINDOW CONTEXT MENU

The context menu in the Graphics window has been extended and now provides
additional functionality. What appears in the context menu depends on the currently
selected node in the Model Builder. There is a menu for the geometry (including aseparate menu in the 2D sketch mode), definitions, materials, physics interfaces,
multiphysics, and mesh nodes.
The context menu content is different depending on if there is a preselection in theGraphics window or not. When there is a preselection, new features can be added fromthe menu, taking the preselection as their selection.
The context menu is filtered, for physics for example, so that only the features that canuse the preselection appear in the menu.
If the context menu does not contain what you want, there is a Go To submenu thatyou can use to move to another node in the Model Builder while keeping the

COMSOL MULTIPHYSICS|

15

preselection if possible. You can then right-click again and select the feature that you
want to add.
POWERPOINT® PRESENTATION GENERATOR

You can now generate presentations of COMSOL Multiphysics models as Microsoft®
PowerPoint slide presentations. The presentations include information and plots fromthe model, and you can choose between a default presentation or a detailed
presentation. You can also create user-defined presentations with custom content anddefine and use presentation templates. To add a presentation, right-click the Reports
node and the choose a presentation type from the Presentations submenu.
MISCELLANEOUS NEW AND IMPROVED FUNCTIONALITY• There is a new preference setting on the Graphics and Plot Windows page in the
Preferences dialog box to control the default view when creating new views andwhen clicking the Go to Default View button in 3D in the Graphics toolbar. Also,
some preference settings have moved from this page to the Graphics Interaction page.
In addition, there are three new buttons on the Graphics toolbar buttons: Go to YX
View, Go to ZY View, and Go to ZX View, so that you can quickly move to all six basic
3D views.
• You can add a custom logotype to the Graphics windows. In the Preferences dialog
box, when the Show log on canvas check box is selected on the Graphics and PlotWindows page, you can browse and select a custom logo using an image file. If no
filename is given, the default COMSOL logo is used.
• A new State-Space Controller add-in makes it possible to create and simulate statespace controllers.
• Improved visibility of the unit system setting:- The Unit System section has been moved up in the root node.
- The Same as global system option now also has an identifier of what the global
unit system is in Component nodes.
- The Unit System list also shows which unit system is the same as the global unit
system in Component nodes.
• Large icons can now be used in the regular Graphics toolbar using a new preference
setting on the Graphics Toolbars page in the Preferences dialog box.

16 |CHAPTER 1: RELEASE NOTES• Under Global Definitions and Definitions, you can now group nodes under anotherGroup node so that you can organize those nodes under Group nodes at several levels.
• You can now search for applications in the Application Libraries window with aparticular identifier in the COMSOL Application Gallery(www.comsol.com/models) using the search prefix @appdb: immediately followedby the identifier. This can be useful when communicating with a COMSOL support
or sales representative.
IMPROVED RENDERING OF MATERIALSYou can now choose from a much wider selection of materials for a realistic renderingof the materials in a model: brick, car paint, leather, oil, PCB, rubber, soil, textile, andwood, to mention a few. You can also, for a custom material, add noise and brush lines
as well as an additional color and control some surface properties.

New Geometry and Mesh Functionality
GEOMETRY FUNCTIONALITY• The 2D drawing tools have been improved:- The drawing tools are now easily accessible in the context menu that appears
when right-clicking in a 2D sketch. You can also switch between the drawing
tools Polygon, Circular Arc, Interpolation Curve, Quadratic, and Cubic while
drawing by using the context menu, which results in a Composite Curve object.
- When drawing a sequence of polygons, circular arc, interpolation curves, andBézier curves, you can finish it by clicking the first point again, which creates a
closed curve; by right-clicking and selecting Finish Polygon (or similar) on thecontext menu, which does not add a new point; or by double-clicking, whichadds a last point.
- You can cancel the drawing tools by pressing the Esc key.
- When the Sketch button is active in a 2D geometry, you can hold down the Alt
key to temporarily toggle snapping to the geometry on and off while drawing or
while dragging a vertex.
- When the Fillet button is selected, you can exit the fillet sketching mode byclicking the Fillet button again; by right-clicking in the Graphics window andselecting Fillet; or by pressing the Esc key.
- The colors have been adjusted or changed. The most noticeable changes are that
auxiliary vertices and edges (for example, in a Circular Arc feature) are now light

COMSOL MULTIPHYSICS|

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gray, and when hovering over an edge or vertex, the red highlighting is weaker
than in previous versions.
• When you use the CAD kernel in 3D and the license includes the Design Module,
you can now use the Boolean operations from the Design Module kernel (Parasolid
kernel).
• In the Work Plane geometry feature, for Plane type set to Edge parallel, the directionsof the xw and yw axes of the local coordinate system were wrong (reversed) inversion 5.5 when the edge was created by a Boolean operation as an intersection of
two faces using the COMSOL geometry kernel. This issue has been fixed in version
5.6.
• For identity pairs, you can now provide a manual search distance to couple moredistant boundaries than the automatic search distance allows. In the new Advanced
section, select Manual from the Search distance list.
MESHING FUNCTIONALITY• Boundary layer meshing is now available on boundaries for creating boundary layer
meshes on a selection of sufficiently planar faces (that is, faces that can be projected
in a plane without inverting anywhere). In the Settings window for 3D Boundary
Layers nodes, you can now select Boundary as the Geometry entity level to selectboundaries where you want to create a boundary layer mesh.
• The Create Edges feature is now available for creating edges in components withoutgeometry and for imported meshes. You can use this functionality to convert
existing mesh edges from an imported mesh into mesh elements or to create newedge elements in empty space.
• For the Create Edges and Create Vertices features, you can now select vertices andedges by coordinates in the Graphics window. In their Settings window, a new
Vertex Specification section is now available, where you can selects Mesh edges andMesh vertices, respectively. A table then appears in a Mesh Edge Selection and Mesh
Vertex Selection section, respectively, where selected edges and vertices are added.
You can also edit the coordinate values in the table manually.
• The new Intersect with Line feature in 2D and Intersect with Plane feature in 3D
make it possible to partition selected edges or domains of a 2D mesh and selectededges or faces of a 3D surface mesh with a specified line in 2D or plane in 3D,
respectively. They are available for meshing sequences of import type.
• The handling of NASTRAN mesh files has been improved so that CBEAM entries
are now read and edge selections are created for each PID (Property ID) that the
CBEAM entries refer to. RBE2 entries are also read, and for each RBE2 entry, a

18 |CHAPTER 1: RELEASE NOTES

vertex selection is created with the fixed grid point of the RBE2. In addition,
depending on the configuration of the dependent grid points of the RBE2, aboundary selection, an edge selection, or vertex selections are added.
• A new mesh variable is now available, called meshelementall, that for each meshelement gives its number in the entire mesh.
• A new mesh quality measure, curved skewness, is now available for mesh statistics
and plotting and as a mesh variable, qualcurvedskewness. It can be useful for
examining the quality of higher-order meshes.
• The transition smoothing for boundary layer meshing and mesh control has been
improved, providing up to 50% reduction in memory requirements and up to 4
times speedup.
• The Avoid inverted curve elements check box is now selected by default in theFree Tetrahedral node’s Settings window. This may change any tetrahedral mesh ofa geometry with curved faces, but is most likely to affect low-resolution meshes.
Also, the algorithm that avoids the inverted element has been improved.
• Some operations for imported meshes have been renamed in version 5.6:
- Ball is now Partition with Ball.
- Box is now Partition with Box.
- Cylinder is now Partition with Cylinder.
- Logical Expression is now Partition by Expression.
- Also, the menu and ribbon toolbar have been reorganized.

New Functionality in the Physics Interfaces
IMPROVED PRESSURE CONDITION FOR INCOMPRESSIBLE FLUID FLOW

The total (or stagnation) pressure can now be specified on inlet and outlet boundaries
for incompressible flow. Both local and averaged values of the total pressure can be
imposed. This new feature functionality can, for example, be used in pumpsimulations.
WEAK INEQUALITY CONSTRAINT

You can now add a Weak Inequality Constraint node on a domain, boundary, edge, orpoint in any physics interface. First you must select Equation-Based Contributions in theShow More Options dialog box. This constraint feature makes it possible to specify acomplementary nonlinear inequality constraint.

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IMPROVEMENTS FOR MOVING MESHES AND DEFORMED GEOMETRIESYou can now press Ctrl+Space to add expressions to moving mesh and deformed
geometry features.

New and Updated Operators, Functions, and Definitions
IMPROVED EDITING OF USER-DEFINED MATERIAL LIBRARIES

There is a new Edit button and context menu option in the Material Browser window.
You can access the Edit button when selecting a user-defined material library. It opens
the selected material library so that it can be edited.
OTHER IMPROVEMENTS FOR USER-DEFINED MATERIAL LIBRARIESThe grouping of materials in a material library is changed so that you now define itusing node groups in the Model Builder. All the built-in material libraries are updated.
Material Library Settings is a new check box in the Show More Options dialog box, under
General. If you select it, it is possible to set a group type of a global Material node group.

The group type can be Library folder to just group materials together, Phase to groupdifferent phases of the same material, or Phase and orientation to group different
orientations of the same phase of a material. There is also a button to update the labelsof all phases and orientations of the same material.
POROUS MATERIAL

For materials under a model component, you can now add Porous Material nodes fordefining porous materials by adding Fluid, Solid, and Immobile Fluid subnodes thattogether form the overall porosity of the materials.
PERFECT VACUUM MATERIALA Perfect Vacuum material is now available in the built-in material library for
representing a vacuum with a density of zero, relative permittivity of 1, relative
permeability of 1, and electrical conductivity of 0.
MERGING MATERIALS

Right-click a material node and choose another material node from the Merge With
submenu to merge the selected material with the other material.
RECENT MATERIALSYou can now add recently used material from a Recent Material menu on the Materials
ribbon toolbar.

20 |CHAPTER 1: RELEASE NOTESIMPROVEMENTS FOR LAYERED MATERIALS

See Ply-Based Modeling Approach.
NEW AND IMPROVED OPERATORSThe following new operators are available:• elemint — Use elementint(gporder,expr) to integrate an expression over eachmesh element using the specified Gauss point pattern.
• elemavg — Use elementavg(gporder,expr) to evaluate the average of an
expression using the specified Gauss point pattern.
• elemgpmin — Use elementpmin(gporder,expr) to evaluate the elementwise
minimum of an expression using the specified Gauss point pattern.
• elemgpmax — Use elementpmax(gporder,expr) to evaluate the elementwise
maximum of an expression using the specified Gauss point pattern.
• laginterp — A Lagrange interpolation operator is available aslaginterp(order,expr). This operator dynamically maps any expression to a
Lagrange field of a specified order and then evaluates on that field in each meshelement. The operator also provides spatial derivatives and a complete Jacobian.
• round — Use round(x,p) to round x to the closest number with precision p(number of decimal digits).
OTHER IMPROVEMENTS• The support for copying and pasting nodes in the Model Builder between sessions
has been extended to include parameters, coordinate systems, selections, nonlocal
couplings, probes, mass properties, variables, views, and pairs.
• Curl and divergence elements of the second kind are now available for simplex meshelements.
• The smoothed functions now accept any unit in their input arguments with thelimitation that both arguments must have the same unit. The output is always
without unit, except for the special derivative functions of fldsmhs and fldsmsign,
which will get a unit of one over the input argument’s unit.
• Import of comma-separated decimals for interpolation functions is now supported.
• You can now define probes for points, in addition to domains, boundaries, andedges.
• For probes, you can now add a new output table for the probe data.

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New Functionality in Studies and Solvers
STUDIES AND STUDY STEP FUNCTIONALITY• You can now right-click a study step and select Reset Solver to Default for Selected
Step to reset the solver to the default for an individual study step.
• The Modal Solver can no longer create a reduced-order model as output. It only
computes a solution using a modal method. Modal reduced-order models are now
created using the new Modal Reduction solver. This solver does not output any
solution, only a reduced-order model. In order to run existing Java® or MATLAB®
code creating a reduced-order model, you must therefore change the solver type.
Similarly, the AWE Solver now outputs either a solution or a reduced-order model.
Existing Java or MATLAB code must therefore be updated, setting the output
property to rom, if reduced-model output is desired.
As a consequence, the Reduced model simulation option has been removed from theModel Reduction study step. To simulate a reduced model, use a separate study withan ordinary Stationary or Time Dependent study step.
• For the Optimization and Parametric Sweep study steps, some of the more advanced
settings are now found in new Advanced sections in their Settings windows.
SOLVER FUNCTIONALITY• A new Changes from Default Settings section in the solver sequence nodes lists allchanges made in the solver sequence with the current value and the default value,so that any changes made to a solver sequence can be easily available.
• The FEAST eigenvalue solver is now available for Eigenvalue and Eigenfrequency
studies and for the Eigenvalue Solver as an alternative to ARPACK, which is based on
Krylov subspace techniques (the Arnoldi algorithm). FEAST is based on analgorithm inspired by density-matrix representation and contour integration
techniques in quantum mechanics. The FEAST algorithm solves generalized
eigenvalue problems and can obtain left and right eigenvectors within an interval ora contour in the complex plane.
• The new Block Navier-Stokes preconditioner is an efficient preconditioner for theincompressible Navier–Stokes equations in the transient regime. The algorithm isbased on block factorization of the Jacobian matrix problem coming from the
Newton–Krylov approach to solving the time and space discretization of theincompressible Navier–Stokes equations. You can specify separate solvers from thevelocity and pressure as subnodes to the Velocity Solver and Pressure Solver subnodes,
which are added automatically.

22 |CHAPTER 1: RELEASE NOTES• An adaptation of the GMRES iterative solver called GCRO-DR is now available.
This method can be useful while solving sequences of linear systems arising from,for example, nonlinear problems. The idea is to retain the subspace determinedwhile solving previous systems and use it to reduce the cost of solving the next
system. This process can be referred to as Krylov subspace recycling. To activate it,
select the Use GCRO-DR check box in the Settings window for the Iterative solver
node.
• New options are available for outputting and interpolating solution data from theTime-Dependent Solver, Plug Flow Solver, Time-Discrete Solver, and Time-Explicit Solver
nodes:- You can now control the stored times as Output times by interpolation, which isthe default value and behaves as the previous Specified values; Steps taken bysolver, which stores the steps taken by the solver, so the solution is notinterpolated, except at the end time, and has a new option to Store every N:thstep, which makes it possible to avoid large solution object; Steps taken by solver
closest to output times, which is a new option where the solution is notinterpolated, except at the end time.
- For Free, Manual, and Intermediate time steps, a new option, Interpolate solution
at end time, is available and enabled by default. When it is enabled, the solver canstep past the last time in the Output times list, leading to the end time being
interpolated. When it is disabled, the solver will not step past the last time in the
Output times list, leading to the end time being solved. This option is not available
for Strict time stepping, because then the end time is always solved. It is also notavailable for the Time-Discrete Solver.
• The time-dependent mesh adaptation feature is now available for the time-explicit
Runge–Kutta and Adams–Bashforth methods. In particular, it can be useful for
discontinuous Galerkin simulations.
• For transient problems, it is now possible to terminate based on the residual. Thiscan be useful for transient contact problems, for example. Without this termination
criterion, the solution-based termination must be set to very restrictive values,
which makes the time stepping inefficient. In the Dependent Variables and Field
nodes’ settings, a new Threshold for updating residual scale setting is available for
automatic residual scaling so that, for time-dependent problems, the residual scale
is updated when a sufficiently large change in the residual is detected during time
stepping.
• A new option for the domain-decomposition solvers — Domain Decomposition(Schwarz) and Domain Decomposition (Schur) — makes it possible to add

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absorbing boundary conditions to the domain boundaries created by the solver.
These boundary conditions can improve the convergence rate of the linear iterativesolver when solving Helmholtz equations, for instance. Some physics, such aspressure acoustics, can automatically add weak contributions that describe theappropriate absorbing boundary conditions. There is also a manual option where
you can input an expression of your own. The added contributions do not affect thecomputed solution.
• The automatic update of the Dependent Variables solver nodes at general variable
updates has been removed. Such updates were previously triggered, for example,
when a new physics interface was added to the model. The automatic update is now
postponed until the solver is run or reset. For most solver uses, this change will notaffect your modeling at all. For rare cases, where you need to manually edit thedependent variable nodes (for example, with manual scales), you might need tomanually refresh the dependent variable list. For such cases, an Update Variables
operation is available on the context menu and the toolbar for Dependent Variables
solver nodes. Using the API, there is also a new updateVariables() method.
• In the Automatic Remeshing node’s Settings window, you can now choose Specified
times and Specified time steps to manually control when to remesh. These options
to remesh at given time instants or to remesh after a given time step can be robust
alternatives to the previous remeshing conditions when the temporal behavior of themoving mesh quality is known.
• You can now manually sweep over outer solution numbers using global parameters
in a parametric sweep. To do so, use the solution number inputs to Index fields inthe Values of Dependent Variables sections in study step node Settings windows. This
was not possible in earlier versions because you had to choose a fixed parametervalue. The index is a single index. This functionality is also available on the solver
level (in the Dependent Variables node).
• There are new options for the times to store when running the time-dependent
solver. You can now choose to store every Nth step taken by the solver and the steps
taken by the solver closest to the specified output times.
• You can now control the absolute tolerance of the time derivatives in the timedependent solvers. To do so, set the global Derivative tolerance method to Manualwith the proportionality factor Time derivative factor, which acts between thetolerance on the variables and their derivatives. Automatic (the default) is the settingused in previous versions. Similarly, you can now control the derivative tolerance
individually for the dependent variables with a Derivative tolerance method and theTime derivative factor. These settings appear in the Absolute Tolerance section of the24 |CHAPTER 1: RELEASE NOTESTime-Dependent Solver node. The Generalized alpha time-dependent solver has also
been improved regarding its termination handling for equations featuring secondorder time derivatives. The algebraic error for first-order time derivatives is now
taken into account for second-order equations.

• You can now solve semiexplicit DAEs of index 1 with explicit time stepping. From
the Algebraic equations list in the Time-Explicit Solver node’s settings, you can choose
to solve the algebraic equations periodically or at every Nth step taken by the solver.
CLUSTER AND BATCH FUNCTIONALITY• You can now right-click Solution nodes and choose Domain Decomposition>Convert
to Domain Decomposition (Schwarz) and Domain Decomposition>Convert to Domain
Decomposition (Schur). This way you can to convert a solver into a similar Domain
Decomposition solver with settings adapted for cluster computing. These options
are mainly intended for running on larger clusters where the domain decomposition
strategy can be faster than the usual solvers.
• You can now reset the history for batch runs with the -resethistory option for
comsol batch.
• To control the scalability assembling mode, which can be useful even when runningon a single node, you can now select the Memory scalability optimization forassembling check box on the Multicore and Cluster Computing page in the Preferences
dialog box. You can then select Off (the default, for no scalability mode), Matrix for
activating scalability mode only for matrix assembling, Vector for activating
scalability mode only for vector assembling, or All for activating scalability mode forall cases. You can also control these options with a -memoptassem option, with thesupported values off, matrix, vector, and all.
• The HYPRE library of linear solvers has been updated to version hypre-2.17.0 andnow supports both OpenMP and MPI.

New and Improved Results and Visualization Functionality
NEW AND IMPROVED DATASET AND EVALUATION FUNCTIONALITY• New Embed 1D and Embed 2 datasets are now available for embedding 1D data
into 2D and 2D data into 3D, respectively.
• A new Partition dataset is available for partitioning a domain with respect to a set ofisolevels. The dataset then adds elements corresponding to the isosurfaces orcontours. It is possible to create a mesh part from a Partition by choosing a partition
dataset in the mesh import node.

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• You can now repeat a player animation for a specified number of times by choosing
Number of iterations from the Repeat list.
• For variables from 0D components, you can now access them during postprocessing
without a full scope. For example, re.T now works, and you no longer have to use
comp1.re.T.
• The new option runCommand in Results nodes can be used to run special functionsin the Method Editor. One example is automatic generation of Intersection Point
datasets in the image plane by the Spot Diagram plot.
• You can now add a Touchstone export node under Export to export Touchstone files,
which are used to describe data for parameters in port networks from RF
simulations.
• In results tables, it is now possible to right-click and delete rows as well as columns
from the table.
• In Data and Plot nodes under Export, you can now specify a separator for theexported data: column, space, tab, comma, semicolon, colon, or a vertical bar(pipe).
• It is now possible to specify a dataset in a plot or evaluation feature but take thesolution parameters from the parent plot or evaluation group if it refers to the same
solution. You can choose From parent from the Solution parameters list, whenapplicable. The solution parameters will be taken from the parent.
• When using a Transformation type other than None in the settings for an Evaluation
Group node, only the final result is returned. You can now select the new Keep childnodes check box to add the results of the child features when using a transformation.
This way you are able to, for example, see which boundaries that have the largest
flux and total conservation in the same table.
• When exporting data from an impulse response plot using a Plot node under Export,
you can now save it in the WAVE audio file (*.wav) format.
• In Mesh datasets, the Deduce the geometry shape function order from the mesh setting
has been replaced with an explicit Geometry shape function setting for choosing theshape function type and order.
NEW AND IMPROVED GRAPHICS AND PLOT FUNCTIONALITY• You can now add material appearance to all 2D and 3D plots. By adding a Material
Appearance plot attribute, you replace the graphics from the parent node with amaterial appearance, providing the possibility for a mixed-mode visualization, wheresome surfaces or volumes are colored according to an expression and others are

26 |CHAPTER 1: RELEASE NOTES

plotted using a given material appearance. You can take the material appearance
from the defined material or define a custom material appearance.
• A Transparency plot attribute is now available for 3D plots to add transparency for
individual surfaces and plots. This way you can create plots with partial transparency.
• An Image plot attribute is now available for embedding images in Surface andVolume plots in 2D and 3D.
• 1D and 2D Table Histogram plots are now available. They are similar to theprevious Histogram plots but take their data from a table or evaluation group. Also,
the 2D Histogram plots are now available without any license requirements.
• A new Table Annotation plot is available to add annotations from a table to a 1D,
2D, or 3D plot.
• For 1D plots, you can now add Line Segment plots to plot line segments. The lines
can be used to indicate some level, for example.
• For 2D and 3D plots, you can now use Point plots for plotting points, torquearrows, and so on. For 2D, you can choose the following point types: Point, Torque,
Rectangle, and Ellipse. For 3D, you can choose the following point types: Point,
Block, and Ellipsoid.
• You can now add a Marker subnode to Line, Surface, and Volume plots in 2D and
3D to add maximum and minimum markers to such plots.
• It is now possible to add error bars to 1D global and point graph plots.
• Graph markers are now available for 1D plots. For markers and max/min plots, you
can prepend the coordinates of their positions.
• There are two new color tables, AuroraAustralisDark and ThermalNarrow, where
the colors do not end in full black and white. Compared to the AuroraAustralis andThermal color tables, these new color tables provide a better contrast when plottedusing both the dark and the light desktop modes.
• 1D Directivity plots now support adding labels for the levels in the plots.
• For Histogram plots, you can now add Filter subnodes to filter the histogram data.
• For 1D function preview plots, you can now plot the frequency spectrum using FFT.
• Function plots are now also available as 2D plots for functions of two variables.
• The Point Graph and Global 1D plots now support plotting discontinuous(discrete) functions. You can choose the function type to be continuous or discrete.
• For plot groups, plot nodes, and plot attributes, you can now choose to use theirlabels as titles in plots.

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• It is now possible to right-click 1D plots and choose an action that copies the plot
data to a table.
• You can now use vectors of coordinates in annotations.
• In Table Graph plots, you can now sort the data points with respect to x- or ycoordinates.
• For Mesh plots, you can now plot higher-order elements, and color and stylesettings are available. When the geometry order is greater than 1, you can control
the resolution. You can also choose to display node points and control the size of
those points. For nonlinear meshes, the normals are now smoothed across elementboundaries.
• The Plot All and Plot All in Group commands now update all plots, not only the lastplot groups that update each window.
• In tables (Table and Evaluation Group windows) it is now possible to delete rows.
• In Octave Band plots where averaging over bands is performed, you can now plot
the data as a graph connecting the centerpoints of the bands using the new line style.
• A From theme option is now available for uniform colors in 2D and 3D line plotsand 1D graph plots to take the color from the chosen color theme.
• You can now add a Graph Marker subnode to 1D Radiation Pattern plots.
• The order in which color legends are added has changed so that it now follows aleft-to-right, top-to-bottom order. For example, when Position is Right, the orderof the color legends is now left-to-right instead of right-to-left as in earlier versions.

New Java® API Methods
LOADING AND SAVING FILES FOR PARAMETRIC SWEEPS

The loadFile(String filePath) and saveFile(String filePath) Boolean
methods are now available to load and save files for the parametric sweep feature.
These functions work if the type of feature is Parametric Sweep and save information
concerning either all combinations or specified combinations; otherwise, they returnfalse. The functions also return false if the operation is not successful; otherwise, they
return true.
IMAGE OBJECT FOR MESH FEATURES

The image() object for mesh features includes a new property to set the selection.
model.mesh("foo").feature("bar").image().set("selection", "main")

28 |CHAPTER 1: RELEASE NOTES

specifies that the feature’s main selection,model.mesh("foo").feature("bar").selection(), will appear in the plot. This is

the default.
model.mesh("foo").feature("bar").image().set("selection",<propname>)

specifies that a property selection,model.mesh("foo").feature("bar").selection(<propname>), will appear in

the plot.
For mesh features that do not have any selection, the selection property is ignored
when plotting.
ONLY PLOT WHEN REQUESTED

The following methods have been added to the API for plotting only when requested:void setOnlyPlotWhenRequested(booleanvalue);

to set if plots selected in the Model Builder only should be updated when the user
explicitly requests it.
boolean isOnlyPlotWhenRequested();returns true if plots selected in the Model Builder only should be updated when theuser explicitly requests it.
IMPROVED SELECTIONS API

The API for selections has been improved, including the following additions andenhancements:• selection.geom(<gtag>) now sets the selection to be all entities in the geometry<gtag>.
• selection.geom(<gtag>,dim) now specifies that subsequent calls to all, set, add,
and remove refer to entities of dimension dim on the geometry <gtag>.
• selection.clear() removes all entities from the selection.
• selection.dim() returns the largest entity dimension on which the selection
applies.
• selection.entities() returns the geometric entities of the selection on thegiven geometry at the largest entity dimension as an integer array.
From version 5.6, for a selection of entities, the method objects() returns featuretags for objects that are created by a feature that creates exactly one geometry object.

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METHODS FOR RETRIEVING THE COLOR IN PLOTS

The following methods are now available:
double[] color = plot.getColor(<propertyname>, <useGraphicsTheme>)
double[] color = plot.getColor(<propertyname>,<colortheme>)

These methods are available for plot groups and plots. The return value is an array with
the RGB values of the color. The property name has to be a property that defines acolor. If the string value of the property is fromtheme, the color will be evaluated using
the color theme. If the string value is an explicit color, that color will be returned.
In the first method, useGraphicsTheme = true means that the model’s graphics
color theme will be used, and useGraphicsTheme = false means that the model’s
image export color theme will be used.
The second method lets you specify the color theme to use, ignoring the model’s
theme.
EXTERNAL INTERFACE AND COSIMULATION

There is a new list for the model object, model.externalInterface(). This list has
the following methods:
model.externalInterface().create(<tag>,<type>)
model.externalInterface(<tag>).set(<property>,<value>)model.externalInterface(<tag>).run()

The run() method exports a file from the feature.
SimulinkCosimulation is the only valid type in version 5.6. To use it requires alicense for LiveLink™ for Simulink®.
SAVING A COPY OF THE MODEL

The syntax model.save(<path>,<saveCopy>) saves a copy of the model, if theBoolean argument <saveCopy> is true. If it is set to false, this call results in a normal
save operation. When saving as a copy, the location of that copy is not remembered, so
the previous location for saving models is retained.
GETTING ROW HEADERS AND ADDING ROWS IN TABLES

For table features (TableFeature), you can now retrieve row headers using the
getRowHeaders() access method.
The syntax TableFeature.addRows() is now available for adding multiple rows to atable using programming

30 |CHAPTER 1: RELEASE NOTESGeneral Backward Compatibility Considerations
COMSOL Multiphysics version 5.6 can open MPH-files saved from COMSOLMultiphysics versions 4.0–5.5.
COMSOL Multiphysics version 5.6 can run Java® files saved from COMSOLMultiphysics versions 4.0–5.5. However, the Java® files may need to be modified inaccordance with information following in this document and may need to berecompiled with the comsol compile command in version 5.6.

Backward Compatibility with Version 5.5
The selections imported from Filter datasets in version 5.5 are now given tags by acorrected scheme that makes them independent of the language setting in COMSOL.
If you have written API code using such selections, the code might need to be updated
to handle the new naming principle.
In version 5.6, the getAdjSparse method has been deprecated and may be removed
in a future version.
In the Octave Plot, the Solid setting for Type is now called Bar, and the Curve setting
is now called Outline. The corresponding API property values are now bar andoutline.
The default value for the compact aggregation setting for the smooth aggregation
AMG multigrid solver, from version 5.6, is set to off.

Backward Compatibility with Version 5.4
GEOMETRY REPRESENTATION ARRAYS

To reflect the new serialization format for 3D objects represented using the COMSOL
kernel, the meaning of the arrays returned from the GeomInfo methods getFace,
getPVertex, and getPEdge applied to a 3D geometry object has changed slightly inversion 5.5. In version 5.4, row 3 of getFace contained the index of the surface in thelist of all manifolds (curves and surfaces) in the geometry object. In version 5.5, it isinstead an index in the list of all surfaces in the geometry object. Similarly, row 5 of
getPVertex and row 9 of getPEdge now contain an index in the list of surfaces
instead of an index in the list of manifolds.

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INTERPOLATION CURVES

For the Interpolation Curve geometry feature, the default end conditions have beenchanged from Zero curvature to None. In the API, the default has been changed fromzerocurv to none. In addition, the algorithm has been changed for the case when Typeis Open curve and Relative tolerance is 0, which can give a slightly different shape of thecurve.
SCALING 2D GEOMETRY OBJECTSIn version 5.4, you could scale and move a set of selected 2D objects in the Graphics
window by dragging its bounding box. In version 5.5, you can still move objects by
dragging, but scaling requires adding a Scale feature in some cases.
FREE QUAD MESHING

Models saved in versions 5.3 to 5.4 with the free quad tessellation method set toAutomatic (in a Free Quad feature) or face meshing method set to Quadrilateral (in a
Swept feature), will, when opened in version 5.5, have the tessellation method or facemeshing method set to Legacy version 5.4 or Quadrilateral (legacy version 5.4),
respectively.
PARTICLE TRAJECTORIES STUDY STEP

The Particle Trajectories study step has been removed in version 5.5. Instead, use aTime Dependent study step, which has exactly the same settings.
IMAGE EXPORT PROPERTIES

For image export features, the properties options, title, legend, logo, and axes
have been split into three properties in version 5.5, one for each spatial dimension. For
example, options1d, options2d, and options3d. axes does not exist in 3D. The
same change has been done for all image() features.

Backward Compatibility with Version 5.3a
ADAPTATION AND ERROR ESTIMATES

The property rmethod has been renamed meshadaptmethod, with additional possible
values. The old property (rmethod) and its values can still be used.
MASS PROPERTIES AND MASS CONTRIBUTIONSIn the Density section, the Integration frame list in previous versions is now called
Density input frame.

32 |CHAPTER 1: RELEASE NOTESIn the API, the corresponding property name has been changed from
integrationFrame to densityFrame.
NO FLUX FORMULATION

The formulation of the No Flux feature has been changed in the Transport of Diluted
Species interface in version 5.4 so that the flux relative to the convective flux is set tozero. The new formulation is used when opening a model from a previous session. In
the previous formulation, the total flux was set to zero.
LEGACY FLAG -DCS.LEFTRIGHTSELECTION HAS BEEN REMOVED

The legacy flag -Dcs.leftrightselection for selections of geometric entities using
left-right click has been removed in version 5.4.
AMD ACML LIBRARIESThe AMD ACML library is no longer supported by AMD. It has been replaced bystandard BLAS and LAPACK as an alternative to Intel MKL. On Linux, the BLIS
library is also available. Intel MKL is still the default BLAS library.
STRICTER SOLUTIONINFO VALIDATIONThe SolutionInfo validation now ensures that SolutionInfo.isValid() returns
true before using other SolutionInfo methods, unless stated otherwise in the
documentation of the methods.

Backward Compatibility with Version 5.3
PDE, BOUNDARY ELEMENTS INTERFACE

The PDE, Boundary Elements interface has been reimplemented and improved.
Backward compatibility is provided for MPH files but not for the Java API.
STABILIZATION IN SOME PHYSICS INTERFACES

Model files created in version 5.3 and earlier retain the old stabilization formulation.
The new formulation is obtained by replacing the physics interface with a new one.
The improved stabilization breaks Model Java-file backward compatibility for timedependent models that contain one of the affected physics interfaces. Please contact
COMSOL Support to learn how to retain backward compatibility for your specific
Model Java-file.

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STORE SOLUTION ON DISKThe Store solution on disk option has been removed.
FUNCTIONS IN GEOMETRY FEATURES

The button Rebuild with Updated Functions has been removed from the following
geometry features: Parametric Curve, Parametric Surface, and Sweep. Instead, use theRefresh or Clear Functions button in the function features.
In the API, the method importData() is obsolete for the geometry features
ParametricCurve, ParametricSurface, and Sweep. Instead, use the refresh()method in the function features.
PARTICIPATION FACTOR

Support for participation factors in the eigenvalue solver has been replaced by a new
and improved Participation Factors feature, which is available under Definitions>Variable
Utilities in a model component for computing participation factors in structural
simulations.
INTERPOLATION CURVES

For interpolation curves, in the case when relative tolerance is zero (which is thedefault), the algorithm in 5.3a has changed so that the shape of the curve becomessomewhat different (while still interpolating the given points).
ITERATIVE SOLVERSFor the iterative solvers, the error handling mechanism has been improved tocontribute to a general robustness of the computation. The improved mechanism isenabled per default and can give the following effects for nonlinear iterations:• Increased total number of linear iterations• Failure with the error “Divergence of the linear iterations”, if the preconditioner isextremely ill-conditioned.
UNITS IN THE SIZE EXPRESSION NODEThe size expression is now interpreted in the model component’s unit system rather
than in the geometry’s unit system. Also, the spatial coordinates (x, y, z, and so on) are
now always in the component’s unit system. In version 5.3, when evaluating on a grid,
the spatial coordinates were in the geometry’s unit system.

34 |CHAPTER 1: RELEASE NOTESSTRESS/STRAIN PLOTS

Principal stress/strain plots now evaluate the stresses and strains in the centers of meshelements instead of in the mesh nodes.

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AC/DC Module
New Functionality in Version 5.6
NEW MAGNETIC FIELDS, CURRENTS ONLY INTERFACEThe new Magnetic Fields, Currents Only interface is designed to efficiently computethe lumped inductance matrix of complex circuits in 3D.
UPDATED AND IMPROVED STUDY STEPS• The Time to Frequency Losses study step now uses empirical models (Steinmetz,
Bertotti, or user-defined models) to calculate the iron loss caused by magnetic
hysteresis, eddy currents, and other effects in laminated cores or yokes.
• The Eigenfrequency study is now supported for most of the AC/DC interfaces. In
addition to supporting full-wave cavity mode analysis in the magnetic fields
interface, it is possible to do eigenfrequency analysis of models involving electricalcircuits.
UPDATED ELECTRICAL CIRCUIT FUNCTIONALITY• For time-dependent studies, the Electrical Circuit interface has been equipped withan event-based Switch. This allows you to model the more or less instantaneous onoff switching of certain connections in the circuit.
• The Electrical Circuit interface has been equipped with Parameterized Subcircuit
Definitions. Together with the Subcircuit Instance, these definitions enable you tocreate your own “building blocks” containing smaller circuits and use multiple
parameterized variants of those in your larger circuit.
• For the Electrical Circuit interface, the state, event, and solver machinery has been
improved; especially the transient modeling of nonlinear (semiconductor) devices,which has become more stable.
NEW MAGNETIC MATERIALSThe AC/DC Material Library has been extended with magnetic materials from
Bomatec®. The materials include all the NdFeB standard grades; NdFeB (bonded,injection molded, and extruded); Ferrite (isotropic, anisotropic, and injection
molded); SmCo (injection molded); SmFeN (injection molded); SmCo5 andSm2Co17 grades; and AlNiCo (cast and sintered).

36 |CHAPTER 1: RELEASE NOTESOTHER NEW AND UPDATED FUNCTIONALITY• New default plots have been developed specifically for physics interfaces that
support magnetic fields: The Magnetic Fields interface, the Magnetic Fields, No
Currents (Boundary Elements) interface, the Rotating Machinery, Magnetic
multiphysics interface, the Magnetic and Electric Fields interface, the Magnetic
Field Formulation interface, and the new Magnetic Fields, Currents Only interface.
• For the Charge Conservation feature in the Electrostatics interface, the list of
dielectric material models has been extended with the option Ferroelectric, formodeling electrostatics in a ferroelectric material.
• The Coil domain feature has been equipped with support for a slanted cut. Selecting
the Slanted cut check box is needed for cases where the natural direction of thecurrent (or the wires) is at an angle with respect to the input or output normal. A
typical example is a helical coil, where the input and output boundaries represent a
periodicity plane.
• The Magnetic Field Formulation interface now supports new discretization shapefunctions referred to as the Nédélec curl element of the second kind (curl type 2).
The curl type 2 element provides full polynomial orders in all directions for eachfield component. The curl type 2 element is available for simplex mesh elements
only.

New and Updated Models in Version 5.6
Updates to the AC/DC Module Application Library:• Several tutorial models have been updated, most notably the Cable Tutorial Series.
The Cable Tutorial Series has been updated to include the short-twisted periodic
configuration. This configuration makes it possible to solve a twisted, three-phasearmored cable model in a matter of seconds rather than hours.
In addition, the following four new models are now available:• Inductance Matrix Calculation of PCB Coils. This model shows how to computethe inductance matrix of a series of conductors with the Magnetic Fields, Currents
Only interface.
• Hysteresis in Ferroelectric Material, which demonstrates how to analyze thenonlinear polarization behavior of ferroelectric materials.

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• High-Voltage Insulator. This type of insulator is widely used in high-voltage powertransmission lines to support the weight of suspended conductors without allowing
the current to flow through the tower to ground.
• Position Optimization of Grading Rings. This model extends the High-Voltage
Insulator model and shows how to use the Optimization interface to find the
optimum position of the grading rings.

Backward Compatibility with Version 5.4 and Earlier
REMANENT FLUX DENSITY MATERIAL PROPERTY GROUP

With the introduction of the remanent flux density material property group, support
for the remanent flux density constitutive relation with the relative permeability given
by an effective medium has been dropped. In other words, a linear (hard) magnetic
material where Br is set and μr given by an Effective medium is no longer supported.
User-defined expressions for μr are still possible and may serve as a substitute.
REFACTORING OF MODEL INPUTS

For all AC/DC Module interfaces, some model input functionality has been moved to
the Default Model Inputs node.
For a temperature-dependent boundary material used in an Impedance boundary
condition, for example, this means the default model inputs should be used, rather
than the feature’s model input section (the model input section in the Impedanceboundary condition’s Settings window).
For more frequently occurring combinations, like a temperature-dependent domainmaterial and a current conservation law, both the default model inputs as well as thefeature’s model input section are available as a means of specifying the temperature.

38 |CHAPTER 1: RELEASE NOTESAcoustics Module
New Functionality in Version 5.6
PORT BOUNDARY CONDITION FOR ELASTIC WAVE PROPAGATIONThe new Port boundary condition, available with the Solid Mechanics interface, isdesigned to excite and absorb elastic waves that enter or leave solid waveguidestructures. A given Port condition supports one specific propagating mode.
Combining several port conditions on the same boundary allows a consistenttreatment of a mixture of propagating waves, for example, longitudinal, torsional, andtransverse modes. The combined setup with several Port conditions provides a superior
nonreflecting condition for waveguides to, for example, a perfectly matched layer(PML) configuration or the Low-Reflecting Boundary. The port condition supports
S-parameter (scattering parameter) calculation, but it can also be used as a source tojust excite a system. The power of reflected and transmitted waves is available inpostprocessing. To compute and identify the propagating modes, the Boundary Mode
Analysis study is available in combination with the port conditions.
NONLINEAR ACOUSTICS, TIME EXPLICIT

The new Nonlinear Acoustics, Time Explicit interface is used to model high-amplitudenonlinear pressure waves in fluids. The interface is based on the discontinuous Galerkin(dG or dG-FEM) method and uses a time-explicit solver. The method is very memory
efficient and can solve problems with many million degrees of freedom (DOFs). The
method is also well suited for distributed computing on clusters. The interface exists
in 2D, 2D axisymmetric, and 3D geometries. The formulation used is suited formodeling progressive wave phenomena when the cumulative nonlinear effects surpassthe local nonlinear effects, and the model is consistent with the second-orderWestervelt equation. The interface is multiphysics enabled and can be coupled with the
Elastic Waves, Time Explicit interface to model vibroacoustic problems. Absorbing
layers are used to set up effective nonreflecting boundary conditions. Consistenthandling of material discontinuities is enabled when modeling transitions between
materials like, for example, different tissues and fluids. Pair features allow the use ofnonconforming or discontinuous meshes at boundaries between materials. For
modeling shock formation and propagation, special weighted essentiallynonoscillatory (WENO) limiters can be used in combination with linear elements.
Transient adaptive mesh refinement can be used to speed up the solution of nonlinear
acoustic problems with propagating pulse signals.

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NONLINEAR THERMOVISCOUS ACOUSTICS

The Nonlinear Thermoviscous Acoustics Contributions feature adds the necessarycontributions to the Thermoviscous Acoustics, Transient interface in order to model
nonlinear effects in a transient thermoviscous simulation. The contributions allow
modeling of vortex shedding that may happen at sudden expansions, like in a
perforate, a grill, or at a miniature sound port. With the second-order density
representation option, the feature can also capture the nonlinear effect associated withhigh sound pressure levels that require a nonlinear representation of the equation ofstate. Using this option, cumulative nonlinear effects are also captured. Stabilization
has been added to the thermoviscous acoustics interfaces, which is essential when using
the Nonlinear Thermoviscous Acoustics Contributions feature for solving highly nonlinear
problems.
LUMPED PORT BOUNDARY CONDITION IN PRESSURE ACOUSTICS

The new Lumped Port boundary condition in Pressure Acoustics, Frequency Domain
connects a waveguide or duct inlet or outlet to a lumped representation element. Thiscan be an Electrical Circuit (with the AC/DC Module), a two-port network defined
through a transfer matrix, or a lumped representation of a waveguide. Basically, it
couples the end of a waveguide to an exterior system that has a given lumped
representation. Several representations and sources exist to describe the lumped system
as well as to excite the system. When using the lumped port representation, it isassumed that only plane waves propagate in the acoustic waveguide.
NEWS IN PRESSURE ACOUSTICS, BOUNDARY ELEMENTS (BEM)
INTERFACES

For acoustically large models, that is, problems that contain many wavelengths (highfrequency or large domains), a new Stabilized Formulation option can be enabled toensure efficient convergence at the cost of some additional degrees of freedom. For
small to medium problems, the default formulation should be used. When the newstabilized formulation is enabled, a new dedicated solver suggestion is also used.
In the Pressure Acoustics, Boundary Elements interface, a new Exclude Boundary feature
has been added. The feature can be used to exclude boundaries from the BEM model.
The feature is particularly useful when using the interface in half space or infinite baffle
setups.

40 |CHAPTER 1: RELEASE NOTESMOIST AIR MATERIAL GENERATED FROM THERMODYNAMICS

Defining moist air is now possible using the Predefined System for Moist air in the
Thermodynamics feature. This functionality is available with the new Liquid & Gas
Properties Module.
THERMOVISCOUS BOUNDARY LAYER IMPEDANCE BOUNDARY CONDITION

The new Thermoviscous Boundary Layer Impedance boundary condition, in Pressure
Acoustics, Frequency Domain, adds the losses due to thermal and viscous dissipation in
the acoustic boundary layers at a wall. The losses are included in a locally homogenizedmanner, where they are integrated through the boundary layers analytically. The
condition is applicable in cases where boundary layers are not overlapping. That is, it
is not applicable in a very narrow waveguide (with dimensions comparable to theboundary layer thickness) or on highly curved boundaries.
GENERAL NEWS IN THE TIME-EXPLICIT INTERFACES

The time-explicit interfaces that use the discontinuous Galerkin formulation (dGFEM) come with new functionality and performance improvements:• General speedup of up to 30% when solving models with the Pressure Acoustics;
Convected Wave Equation; and Elastic Waves, Time Explicit interfaces in 3D.
• Reformulation of the Pressure Acoustics, Time Explicit interface for 2D and 2D
axisymmetry reduces the number of degrees of freedom (DOFs) solved for with up
to 25%.
• The time-explicit dG-FEM method has been extended to work on all mesh types.
This, for example, allows the use of a structured mesh in thin elastic structures. In
general, using a structured mesh gives a memory reduction and a speedup.
• The Elastic Waves, Time Explicit interface is now also present in a 2D axisymmetricformulation.
• The time-explicit interfaces can now be solved in combination with systems of
ODEs (ordinary differential equations). This can, for example, be used to formulate
user-defined frequency-dependent impedance boundary conditions in acoustics.
• The time-explicit interfaces can now be solved in combination with an algebraic
equation (an equation with no time derivatives).
NEW IN RAY ACOUSTICS

In the Ray Acoustics interface, there are several news related to the generation andanalysis of the impulse response. The rendering and computation time of the impulse
response has been greatly improved. The steps to set up the impulse response are now

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also simpler and consistent. It is now also possible to analyze and compute thequalitative room acoustic metrics, like clarity, definition, and reverberation times,
based on the computed impulse response. This is done using a new Energy Decay
subfeature that can be added to an Impulse Response plot. It is also possible to export
the computed impulse response signal to .wav format for further analysis.
Significant speedup of the computation and the analysis of the impulse response:• A significant speedup of the initial computation and rendering of the impulse
response is achieved in version 5.6 compared to older releases.
• Ray data in the Impulse Response plot is now stored in cache. This ensures a very fast
rendering time when changing options in the impulse response plot.
New improved impulse response analysis functionality with the Energy Decay
subfeature:• More precise computation of the arrival time at the receiver when the source or thelast reflection is close to the receiver. Direct sound gets a consistent arrival timecomputation and summation of power.
• Analysis of the impulse response with room acoustics metrics to compute:
Reverberation times (T20, T30, and T60); clarity; definition; EDT; speechtransmission index (STI); and the modulation transfer functions.
• Improved filter kernel functionality for the IR computation with user-defined
definition of the filter kernel and visualization of the filters.
BACKGROUND FLUID FLOW COUPLING SUPPORTS HIGH MACH NUMBERFLOW

The Background Fluid Flow Coupling multiphysics feature now supports High Mach
Number Flow interfaces as the source for the flow data.
NEWS FOR THE ACOUSTIC PORT CONDITIONS

Automatic Boundary Conditions for Numeric Ports in Thermoviscous Acoustics
When the Numeric option is used in the Port feature in a Thermoviscous Acoustics,
Frequency Domain model, it now automatically detects the boundary conditions appliedon the adjacent waveguide boundaries. The conditions are then automatically included
when computing the mode shape of the propagating acoustic mode. The Numeric
option supports the use of Wall, No Slip, Isothermal, Adiabatic, and Symmetry
conditions.

42 |CHAPTER 1: RELEASE NOTESFrequency Sweep and Numeric Ports
In pressure acoustics, a new option has been added to compute the mode shape andcutoff frequency for numeric modes in lossless systems. For a model without any losses,
the new Computed lossless mode cutoff frequency option makes it possible to run afrequency sweep using a single Boundary Mode Analysis study for each port.

Power Scaling Option for Port Conditions
The port features in Pressure Acoustics, Frequency Domain and Thermoviscous Acoustics,
Frequency Domain now have the option to use power scaling for the mode shapes. The

default is to use amplitude scaling. The power option is equivalent to the default
known from RF applications. With the power scaling option, the computed scatteringparameters can be directly related to the power carried by a specific mode.
NEW THREE-PARAMETER APPROXIMATION JCAL POROACOUSTIC MODEL
IN POROACOUSTICS

A new Three-parameter approximation JCAL model option has been added to the
Poroacoustic feature in Pressure Acoustics, Frequency Domain. The model is anapproximation to the existing Johnson-Champoux–Allard–Lafarge (JCAL) model but
only requires three porous parameters to be specified. The three parameters are thePorosity, the Median pore size, and the Standard deviation in the pore size distribution.
IMPROVED STABILIZATION FOR LINEARIZED NAIVER-STOKES PHYSICS

The stabilization in the Linearized Navier-Stokes physics interfaces has been improved
with a more consistent formulation. Specifically, the balance between the stabilization
contributions of the continuity, momentum, and energy equations has been improved.
SOLVER SUGGESTIONS FOR DOMAIN DECOMPOSITION AND SHIFTEDLAPLACE METHODSFor pure Pressure Acoustics, Frequency Domain models, two new iterative solver
suggestions have been added; one that uses the Shifted Laplace approach (thetechnology was added in version 5.5) and one that uses Domain Decomposition. The
iterative solver suggestions now automatically add the necessary equation
contributions on domains and at boundaries (between domains) to ensure an efficientsolver. The Shifted Laplace solver is efficient for solving large problems on a single
machine with a lot of RAM while the Domain Decomposition method is suited forsolving very large problems using distributed computation on a cluster.

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NEW SETTINGS FOR SOLVING TRANSIENT ELASTIC WAVE PROBLEMSWITH SOLID MECHANICS

New settings have been introduced in the Solid Mechanics interface that ensure a correctand efficient solver setup when solving elastic wave problems in the time domain. The
settings are similar to the existing settings in the transient acoustics interfaces. At thephysics level, a new Transient Solver Settings section has been introduced with an option
to specify the Maximum frequency to resolve.
LICENSE UPDATE FOR PIPE ACOUSTICS

The Pipe Acoustics, Frequency Domain and Pipe Acoustics, Transient interfaces are now
available with either the Acoustics Module or the Pipe Flow Module.
IMPORTANT ENHANCEMENTS AND UPDATES IN THE ACOUSTICS MODULE• Predefined postprocessing variables for the effective speed of sound magnitude andprinciple directions for Anisotropic Acoustics.
• Computation of all intensity variables in the scattered field formulation.
Background, scattered, and total field variables are computed using a new option(check box) on the Background Pressure Field feature and on the Incident Pressure
Field feature in Pressure Acoustics. This allows for easy postprocessing of incident andscattered acoustic power when modeling scattering problems.
• Postprocessing variables for total, scattered, and background fields have been madeconsistent across the acoustics interfaces such that variables are defined in all cases.
For example, the total, scattered, and background sound pressure levels are now
defined as: phys.Lp_t, phys.Lp_s, and phys.Lp_b, respectively.
• It is now possible to compute accurate boundary fluxes in the Pressure Acoustics
interface. This is an advanced option in the Discretization section at the top physics
level in the user interface.
• In the Acoustic Diffusion Equation interface, tables defining properties in frequency
bands are now imported with “replace” and you can only import a table that has the
expected size.
• Consolidation of the stress feature in the Linearized Navier-Stokes andThermoviscous Acoustics interfaces.
• The predefined power variables of the Port boundary conditions have beenreformulated such that they can directly be used in optimization models.
• Additional postprocessing variables have been added to the Elastic Waves, Time
Explicit interface.

44 |CHAPTER 1: RELEASE NOTES• The new function plot preview with FFT option is useful to obtain the frequency
content of any signal without the need of setting up a new FFT study step. This isspecially relevant for transient models with a known input signal. The frequency
content of the signal can be analyzed beforehand and the meshing and solver
options can be adjusted according to the frequency content.

New and Updated Model Examples in 5.6• Propagation of Seismic Waves Through Earth (new)• Submarine Target Strength (new)• High-Intensity Focused Ultrasound (HIFU) Propagation Through a Tissue
Phantom (new)• Electric Motor Noise: Analysis of a Permanent Magnet Synchronous Motor (new)• Nonlinear Slit Resonator (new)• Topology Optimization and Verification of an Acoustic Mode in a 2D Room (new)• Nonlinear Propagation of a Cylindrical Wave — Verification Model (new)• Piezoelectric MEMS Speaker (new)• Pressure Reciprocity Calibration Coupler with Detailed Moist Air Material
Properties (new)• Loudspeaker Driver - Frequency Domain Analysis (updated)• Vented Loudspeaker Enclosure (updated)• Piezoelectric Tonpilz Transducer with a Prestressed Bolt (updated)• The Brüel & Kjær 4134 Condenser Microphone (updated)

Backward Compatibility with Version 5.5
The handling of tables with data entered in frequency bands in the Acoustic Diffusion
Equation interface has been improved. Data can now be stored for all three input types.
To retrieve the old behavior for user-defined bands, change the parameter names
N_band, alphaN, JiN, QN, alphafN, TLN, and qpn to N_band_ud, alphaN_ud,
JinN_ud, QN_ud, alphafN_ud, TLN_ud, and qpn_ud where needed.
For example:
model.component("comp1").physics("ade").feature("ps1").set("N_band_ud", new int[][]{{1},{2},{3}});

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model.component("comp1").physics("ade").feature("ps1").set("qpN_ud", new int[][]{{1},{0},{0}})Backward Compatibility with Version 5.4
For the Pressure Acoustics interfaces, the following features have been removed fromthe Fallback feature submenu to the Pair features: Matched Boundary, Exterior Field
Calculation, Port, Plane Wave Radiation, Circular Wave Radiation, and Spherical Wave
Radiation.

Backward Compatibility with Version 5.3a
For the Linearized Navier–Stokes interfaces, the override rules for boundary
conditions have changed. To obtain the old behavior of a model, disable the boundary
conditions that should not contribute to the solution.

Backward Compatibility with Version 5.3
For the Linearized Euler, Transient interface, initial conditions are only used for the
dependent variables. The initial conditions for the time derivatives have therefore been
removed. For a model with fields rho, u, and p, remove the Java® lines setting
drho/dt, du/dt, and dp/dt (these parameters change names when the field names
change).

46 |CHAPTER 1: RELEASE NOTESBa t t e r y De s i g n Mod u l e
New Functionality in Version 5.6
GENERAL NEW FUNCTIONALITY• The module name has changed from Batteries & Fuel Cell Module to Battery
Design Module.
• The NMC 811 Electrode Material has been added to the Battery Material Library.
ELECTROCHEMISTRY INTERFACES• A Dissolving-Depositing Species section has been added to the Separator node of the
Lithium-Ion Battery; Battery with Binary Electrolyte; and Tertiary Current
Distribution, Nernst–Planck interfaces.
• The stoichiometric coefficients for the dissolving-depositing species table are now
reset to the default value of 0 when duplicated.
• For the Electrode Reaction and Porous Electrode Reaction nodes of the Tertiary
Current Distribution, Nernst–Planck interface, a new option for the linearization ofconcentration dependence for low concentrations of the Butler–Volmer kinetics
expression type is now available when using either mass action law or lumped
multistep as the exchange current density type.
• A new From material option has been added for the Local current density setting in
the Electrode Kinetics section in electrode reactions of all electrochemistryinterfaces.
• A new property, Physics vs. Materials Reference Electrode Potential, has been added
to all electrochemistry interfaces.
• The solver defaults have been updated for most Electrochemistry interfaces.
Geometric and algebraic multigrid solvers (GMG and AMG) are now automaticallygenerated by the study step nodes. A direct solver will, however, still always be usedby default. Minor changes have also been made to default scales and tolerances.
• The Electrode Surface (eebii) boundary feature, applicable to both exterior andinterior boundaries of electrolyte domains, is now obsolete. It is replaced with a new
Electrode Surface (es) boundary feature, applicable to exterior boundaries only, anda new Perforated Electrode Surface (pes) boundary feature, applicable to interior
boundaries of electrolyte domains only.

BATTERY DESIGN MODULE|

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• The Thin Electrolyte Layer boundary feature is now available for the Electroanalysis
charge conservation model in the Tertiary Current Distribution interface.
• A new Highly Conductive Porous Electrode domain node has been added to thePrimary/Secondary/Tertiary Current Distribution, Lithium-Ion Battery, andBattery with Binary Electrolyte interfaces.
• The irreversible heat source term now contains a contribution from the film
resistance resistive heating.
CHEMICAL SPECIES TRANSPORT INTERFACES• It is now straightforward to apply diffusion coefficients defined by a Chemistryinterface. The input for diffusion coefficients now includes a Source list with theoptions Material and Chemistry. Selecting the latter, it is then possible to pick up
coefficients from any Chemistry interface present in the model.
• The total number of constraints applied on a boundary are now analyzed. When
combining concentration constraints with equilibrium reactions on boundaries, awarning is shown when the system is overconstrained. The constraint analysis isperformed in the following interfaces: Transport of Diluted Species and Transportof Concentrated Species.
• When solving mass transfer problems, iterative algebraic multigrid (AMG) solvers
are now automatically generated in the solver sequences for large models. A direct
solver is also added for convenience.
THERMODYNAMICS• Using the Generate Material Wizard, the resulting material can now be added underglobal Definitions (as well as in a component of any space dimension).
• The time spent evaluating a function from a thermodynamic system has beensignificantly reduced.
• The model object for the Thermodynamics node, accessible from the API, has beenrenamed. It is now accessed in the following manner:model.thermodynamics()

instead ofmodel.capeopen()Java® files from previous versions will continue to run.

48 |CHAPTER 1: RELEASE NOTESTHE CHEMISTRY INTERFACE• It is now possible to balance the reaction formula. To do so, click the Balance buttonin the upper-right corner of the Reaction Formula section.
• The reaction rate is now by default defined from the Mass action law. This waspreviously referred to as the Automatic definition.
• The overall reaction orders when the Mass action law is used are now displayed intext form in the Reaction Rate section. The reaction order for both surface andvolumetric species are displayed.
• The overall forward reaction order and the overall reverse reaction order (whenpresent) are reported. For surface reactions, the reaction order for both surface andvolumetric species are reported.
• The molar mass is now automatically computed from the species chemical formula.
The species name is parsed for elements in the periodic table, and the molar mass iscomputed using the corresponding elemental masses.
- The molar mass is automatically defined when a Species node is created, as well as
when a species is added to a Species Group node.
- When the automatic calculation fails, for example, when descriptive name such as
water is used, the molar mass is set to 0 g/mol.
- When computing a model that contains species for which the molar mass remains
at zero, a warning node is added in the solver sequence.
• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Model Input- Mixture Properties- Species Matching- Calculate Transport Properties- Activity- Extra Dimension
Note that applications created in previous versions retain the original section order.
• The mixture type (diluted species or concentrated species) is now controlled using
the Type list at the top of the Mixture Properties section. It was previously located in
the Species Matching section.
• The section Equilibrium Species Vector has been removed from the Settings
window of the interface.

BATTERY DESIGN MODULE|

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• Thermodynamic properties are now always defined. The Calculate Thermodynamic
Properties section, with the corresponding check box, has been removed.
- The Species Thermodynamic Expressions section is always available in a Species
node.
- The Reaction Thermodynamic Properties section is always available in a Reaction orElectrode Reaction node.
• The Calculate mixture properties check box in the Calculate Transport Properties
section is now enabled by default.
• The ratio of specific heats can now be specified in the Calculate Transport Properties
section. The ratio is defined and announced and can be used in other physics
interfaces.
• The setting to specify that the concentration, or activity, of species does not change
has been renamed. It is now called Constant concentration/activity. It waspreviously called Locked concentration/activity.
• The nomenclature in the tables in the Species Matching table section has been mademore distinct. Species can now be one of the following types: Constant, Variable,
Solvent, or Free species.
• The tables in the Species Matching section no longer contain a Reaction rate column.
• The table at the top of the Species Matching table is now named Bulk species tocommunicate that these species are present in the mixture phase.
NEW FEATURES FOR POROUS MEDIA TRANSFER

Two new domain features, the Porous Medium and Unsaturated Porous Mediumfeatures, are available in the Transport of Diluted Species in Porous Media andTransport of Diluted Species interfaces. The new features include support for using the
Porous Material node, also new in version 5.6, for assigning material properties to themultiple phases in a porous medium. The new features have subnodes to define phase
properties. The subnodes follow the same structure as the subnodes available for a
Porous Material.
The Dispersion and Volatilization settings in partially saturated porous media havebeen removed from the interface level of the Transport of Diluted Species in PorousMedia and Transport of Diluted Species interfaces. This functionality is now available
in the subnodes of the new features.
The new domain features replace the previously available Porous Media Transport
Properties and Partially Saturated Porous Media features. When opening a model
created in a previous version, the previous features are kept in the model.

50 |CHAPTER 1: RELEASE NOTESNew and Updated Applications and Models in Version 5.6• A new Lithium-Sulfur Battery model has been added.
• A new 1D Isothermal Nickel-Cadmium Battery model has been added.
• A new Lithium Battery Pack Designer application has been added.

Backward Compatibility with Version 5.4• The Java API migration code handling the new lithium insertion and lithium metal
kinetics in the Lithium-Ion Battery interface and the Single Particle Battery
interface assumes that ka=kc and cl_ref have been manually set in Java; if this is
not the case, backward compatibility may be affected.
• The default stoichiometric number for Dissolving-Depositing species has beenchanged to 0 (from 1). Java API backward compatibility may be affected.
• The Tertiary Current Distribution, Nernst-Planck interfaces have changed default
settings to use the Nernst equation option for the equilibrium potential, ButlerVolmer for the kinetics expression type, and Mass action law for the exchange
current density type. Java API backward compatibility may be affected.

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CAD Import Module, Design Module,and LiveLink™ Products for CAD
New Functionality in Version 5.6
CAD IMPORT MODULE GEOMETRY KERNEL UPGRADE

The CAD Import Module, the Design Module, and the LiveLink™ products for CAD
utilize the Parasolid® geometry kernel from Siemens PLM for solid modeling
operations, geometry repair, and defeaturing. (Without these products, a COMSOLnative geometry modeling kernel is used.) The CAD Import Module released with
COMSOL version 5.6 includes an upgraded version of the Parasolid kernel. As a result,a number of stability issues have been fixed, which makes the import of CAD models
and solid operations more robust.
• The CAD file import functionality included with these products has been extended
to support new versions for some of the supported file formats (see under Read from
File, CAD on www.comsol.com/products/specifications/cad).
• The import of CAD assemblies containing several instances of the same part has
been improved and is now faster compared to previous versions.
• You can use the new Delete Interferences tool to detect interference between
objects. The tool detects touches, intersections, gaps, and containments.
• The new Check feature can be used to detect faults in CAD objects.
• The Repair feature now has two new check boxes. The Check resulting objects checkbox enables checking for remaining faults in the CAD objects. The Repair face-toface inconsistencies in solids check box has been added to repair these type of faults
in solid CAD objects.
• Form assembly has been improved in the CAD kernel case for better imprint andpair generation when overlaps and gaps occur between objects.

New Functionality in the Design Module in Version 5.6• The Design Module adds support for more advanced Boolean operations that canbe enabled in the settings of a 3D geometry by the new Design Module Boolean
operations check box. The default of this check box is controlled by a preference
setting.

52 |CHAPTER 1: RELEASE NOTES• The new Horizontal and Vertical constraints make it easier to constrain straightedges to be parallel to the x- and y-axes.
• Measuring dimensions have been introduced to enable adding dimensions that do
not constrain the geometry but instead can be used as a measurement. To change adimension into a measuring dimension, toggle the padlock icon to the right of thedimension value.
• You can now create a parameter from a dimension by selecting its Create parametercheck box. The parameter can be used in geometry, mesh, and physics, for example,
with some restrictions. When used in the expression of another 2D geometry
feature, the expression must depend linearly on the parameter. Parameters can becreated from both constraining and measuring dimensions.
• A new context menu displayed when right-clicking in the Graphics window enables
a more efficient workflow when adding constraints and dimensions to a drawing in
Sketch mode.
• The new Constrain button in the Sketch toolbar determines whether constraints canbe created automatically when snapping to geometry occurs while drawing or whiledragging a vertex. While drawing consecutive segments of a Polygon that snap tobeing perpendicular, a Perpendicular constraint will be created automatically when
the Constrain button is enabled.
• It is now possible to exit the smart Constraint and smart Dimension modes bypressing the Esc key.
• It is now possible to add the Equal Distance constraint to three preselected entities.
The constraint will be applied to the distance between the first and second entities
and the distance between the second and third entities, according to the order inwhich the entities were selected.
• To enable a more efficient workflow when adding dimensions to a geometry, thedimension value text field gets focus immediately after a dimension has been added.
• Dragging of vertices, edges, and constraint and dimension symbols is now enabledeven when a button in the Constraints or Dimensions group in the Sketch toolbar
is selected.

New Functionality in LiveLink™ for AutoCAD® in Version 5.6
The LiveLink™ interface now supports AutoCAD® 2021.

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53

New Functionality in LiveLink™ for Inventor® in Version 5.6• The LiveLink™ interface now supports Inventor® 2021.
• The new tutorial model Geometric Parameter Optimization of a Bracket
demonstrates how to set up the parameter optimization of a geometry, which issynchronized by the LiveLink interface when several geometric constraints are
required to maintain the design intent.

New Functionality in LiveLink™ for PTC® Creo® Parametric™ in
Version 5.6• The LiveLink™ interface now supports PTC® Creo® Parametric™ 7.0.
• Support for PTC® Creo® Parametric™ 3.0 is no longer available by the LiveLink™
interface. File import of PTC® Creo® Parametric™ 3.0 continues to be supported.
• The new tutorial model Geometric Parameter Optimization of a Bracket
demonstrates how to set up the parameter optimization of a geometry, which issynchronized by the LiveLink interface when several geometric constraints are
required to maintain the design intent.

New Functionality in LiveLink™ for Revit® in Version 5.6
The LiveLink™ interface now supports Revit® 2021.

New Functionality in LiveLink™ for Solid Edge® in Version 5.6• The LiveLink™ interface now supports Solid Edge® 2021.
• The new Geometric Parameter Optimization of a Bracket tutorial demonstrates
how to set up the parameter optimization of a geometry, which is synchronized by
the LiveLink interface when several geometric constraints are required to maintainthe design intent.
• The updated Electrical Heating in a Busbar Assembly tutorial now analyzes alarger busbar assembly designed to conduct a direct current from a current source
to the anode in an electrolysis process. Selections defined in the CAD assembly areused to assign materials and boundary settings in the simulation.

54 |CHAPTER 1: RELEASE NOTESNew Functionality in LiveLink™ for SOLIDWORKS® in Version 5.6• The LiveLink™ interface now supports SOLIDWORKS® 2021.
• The new tutorial model Geometric Parameter Optimization of a Bracket
demonstrates how to set up the parameter optimization of a geometry, which issynchronized by the LiveLink interface when several geometric constraints are
required to maintain the design intent.

Backward Compatibility with Previous Versions
BACKWARD COMPATIBILITY WITH VERSION 5.3A

The new fillholes property has been added for the Import function. The following
applies:• The combination of the fillholes property set to on and the knit property set tosolid is equivalent to the knit property set to solid in previous versions.
• The combination of the fillholes property set to off and the knit property set
to surface is equivalent to the knit property set to surface in version 5.3a.
• The combination of the fillholes property set to on and the knit property set tosurface is equivalent to the knit property set to surface in version 5.3 andprevious versions.
The new fillholes property has been added for the Knit function. The Knit
function with the fillholes property set to on corresponds to the Knit function inprevious versions.

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55

CFD Module
New Functionality in Version 5.6• The total (or stagnation) pressure can now be specified on inlet and outlet
boundaries for incompressible flow. Both local and averaged values of the totalpressure can be imposed. This new feature functionality can, for example, be usedin pump simulations.
• There are three new predefined options for the Turbulent intensity: Low, Medium, andHigh, on inlets and open boundaries. A new Geometry based default option has been
introduced for the Turbulence length scale on inlets.
• The Fully developed flow option on inlets and outlets and the Mass flow option on
inlets have a new default setting, Apply condition on each disjoint selection separately.
This option sets up a separate equation for each disjoint boundary selection.
• Warnings for disjoint selections have been added in the Fan, Interior Fan, and Grillefeatures.
• The External Fluid Interface feature has been replaced by the Free Surface feature.
• The Mass Transfer feature in the Euler-Euler Model interfaces has been revised for
improved conservation of momentum, and there is also a new predefined
Nonequilibrium model option available under Mass transfer model.
• The Phase Transport interface now supports pseudo time stepping. A Periodic
Condition and an Open Boundary condition, available on boundaries exterior to
the Phase and Transport Properties feature, have also been added. The Phase
Transport interface now also provides improved support for deforming and rotating
domains, including the Interior Wall boundary condition.
• The Phase Transport, Mixture Model interfaces have been reformulated and are
now based on the mass-averaged velocity field. These interfaces can now be used forcompressible, dispersed, multicomponent mixture simulations. It is now also
possible to couple separated and dispersed multiphase flow interfaces.
• A new physics area, Nonisothermal Mixture Model, containing physics interfaces for
simulating laminar and turbulent nonisothermal n-phase flow, has been added
under Multiphase Flow in the Fluid Flow branch. All RANS turbulence models aresupported. The multiphysics interfaces couple a laminar or turbulent interface witha heat transfer interface and a phase transport interface using three multiphysics

56 |CHAPTER 1: RELEASE NOTES

coupling nodes: Nonisothermal Flow, Mixture Model, and Nonisothermal Mixture
Model.
• An Open Boundary condition has been added in the Level Set interface.
• The Two-Phase Flow, Level Set and Two-Phase Flow, Phase Field laminar andturbulent interfaces have been restructured. The Level Set and Phase Fieldinterfaces now have two Initial Values nodes by default, and the previously used
Initial Interface nodes have been made obsolete. Instead, the phase interfaces areautomatically detected and the initial distribution of the level set or phase field
function is solved for in the Phase Initialization study step.
• New options for averaging density and viscosity across phase interfaces have been
added in the Two-Phase Flow, Level Set and Phase Field interfaces. In addition to
the default volume average, smoothed Heaviside functions and harmonic volume
averages can be used for both density and viscosity averaging. For viscosity
averaging, mass average and harmonic mass average are also available.
• The new physics interface, Shallow Water Equations, Time Explicit, for modelingdepth-averaged free surface flows, has been added under Shallow Water Equationsin the Fluid Flow branch.
• The Porous Media Transport Properties feature in the Transport of Diluted Species
in Porous Media interface has been replaced by a Porous Medium feature
containing two subnodes: Fluid and Porous Matrix. The Porous Matrix node
includes support for Porous Material, which is also new in version 5.6.
• In the Heat Transfer in Fluids interface, the Heat transfer in porous media check box
has been removed, and the Porous Medium feature is now always available. It has
been restructured and now contains two subnodes: Fluid and Porous Matrix.

New Models in Version 5.6
There are two new dispersed multiphase flow models under Multiphase Flow in the
Application Library. The model Droplet Rising Through a Suspension simulates an oil
droplet rising through an initially stratified suspension, with a dense layer between two
clear layers. This model demonstrates the combination of a dispersed multiphase flow
model with a level set model. The model Polymer Electrolyte Membrane Electrolyzer
simulates dispersed multiphase flow, where liquid water is fed to the anode side,
forming oxygen gas on the anode and hydrogen gas on the cathode side, respectively.
Two new models have also been added under Shallow Water Equations in the
Application Library. The model Dam Breaking on a Column simulates the impact of

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57

a water wave on a column. The pressure force on the column is calculated andcompared with experimental results. The model Tsunami Runup onto a Complex 3D
Beach, Monai Valley is an established benchmark case that models a scaled laboratory
experiment of the tsunami runup in the Monai Valley in Japan.

Backward Compatibility with Version 5.5 and Earlier
TURBULENT INTENSITY AND TURBULENCE LENGTH SCALE

The new default value for Turbulent intensity is the same as the old default value,
whereas the new Geometry based default value in general will differ from the old one.
Old Java files with default values for Turbulence length scale should add the line,
model.component("comp1").physics("spf").feature("inl1").
set("LT_list", "user_defined");in the model Java file to retrieve the old length scale.
EULER-EULER MODEL

Results from models using the Mass Transfer feature in the Euler-Euler Modelinterfaces may differ in version 5.6 due to the improved momentum conservation.
PHASE TRANSPORT, MIXTURE MODEL

Since the Phase Transport, Mixture Model interfaces have been revised using a massaveraged formulation to support compressible mixture flows, models built in version
5.5 can return slightly different results when run in version 5.6.
TWO-PHASE FLOWIn the Level Set and Phase Field interfaces, the Initial Interface feature is now obsolete.
It does not need to be replaced because the phase interfaces are automatically detectedfrom the selection of the Initial Values features, and the initial distribution of the levelset or phase field function is solved for in the Phase Initialization study step.

Backward Compatibility with Version 5.4 and Earlier
Models created using the Brinkman Equations and Free and Porous Media Flowinterfaces need to be modified if they apply Forchheimer drag. The previous subfeature
has been replaced by a new setting in the Porous Matrix Properties section.
Old Java files need to replace the line

58 |CHAPTER 1: RELEASE NOTES

model.component("comp1").physics("fp").feature("fmp1").
create("fd1", "Forchheimer", 2);withmodel.component("comp1").physics("fp").feature("fmp1").
set("ktype", "nonDarcianModel");Forchheimer is the default. Also replacemodel.component("comp1").physics("fp").feature("fmp1").
feature("fd1").set("betaF", "value");withmodel.component("comp1").physics("fp").feature("fmp1").
set("cf", "value");

Backward Compatibility with Version 5.3a
MIXTURE MODEL EQUATION FORMULATIONThe Mixture Model equation formulation has been revised to increase the accuracy
and facilitate the solution of a number of problem setups. As a consequence of therevision, old models can return slightly different results in the new version compared
to previous versions.
EULER-EULER MODEL

The results from models using the Euler-Euler Model interfaces may differ in version
5.5 due to the more general formulation for the viscous stress in the momentum
equation for the dispersed phase. The behavior in the old formulation may be
reproduced by dividing the dispersed phase viscosity, μD, by the variable ee.phidPos.
NO FLUX FORMULATION

The formulation of the No Flux feature has been changed in the Transport of Diluted
Species interface in version 5.4 so that the flux relative to the convective flux is set tozero. The new formulation is used when opening a model from a previous session. In
the previous formulation, the total flux was set to zero.
FULLY DEVELOPED FLOW REPLACES LAMINAR INFLOW AND LAMINAR
OUTFLOWThe Laminar inflow and Laminar outflow options on Inlets and Outlets, respectively,
have been replaced with the Fully developed flow option. Models built in versions prior
to 5.4 will contain warnings about obsolete functionality.

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59

Chemical Reaction Engineering
ModuleNew Functionality in Version 5.6
GENERAL NEW FUNCTIONALITY• It is now straightforward to apply diffusion coefficients defined by a Chemistryinterface. The input for diffusion coefficients now includes a Source list with theoptions Material and Chemistry. Selecting the latter, it is possible to pick up
coefficients from any Chemistry interface present in the model.
• The total number of constraints applied on a boundary are now analyzed. When
combining concentration constraints with equilibrium reactions on boundaries, awarning is shown when the system is overconstrained. The constraint analysis isperformed in the following interfaces: Transport of Diluted Species, Transport ofConcentrated Species, and Nernst–Planck Equations.
• The Fully developed flow option (in Inlet nodes) is now available in single-phaseflow interfaces when licensed to the Chemical Reaction Engineering Module.
• When solving mass transfer problems, iterative algebraic multigrid (AMG) solvers
are now automatically generated in the solver sequences for large models. A direct
solver is also added for convenience.
THERMODYNAMICS• Three predefined systems are now available in Thermodynamics: dry air, moist air,and water-steam. These common systems can be set up using a reduced number ofsteps.
• Using the Generate Material Wizard, the resulting material can now be added underglobal Definitions (as well as in a component of any space dimension).
• The time spent evaluating a function from a thermodynamic system has beensignificantly reduced.
• The model object for the Thermodynamics node, accessible from the API, has beenrenamed. It is now accessed in the following manner:model.thermodynamics()

instead of

60 |CHAPTER 1: RELEASE NOTES

model.capeopen()Java® files from previous versions will continue to run.
REACTIVE PELLET BED FEATURES• A new Reactive Pellet Bed feature is now available in the Transport of Concentrated
Species interface.
• The Reactive Pellet Bed feature in the Transport of Diluted Species interface has
been improved in the following manners:- A new Porous Media Diffusion node is now used for defining the diffusion
coefficients for species transport in pellets. When a Chemistry interface is present
in the model, diffusion coefficients defined in this interface can be used.
- The equations solved for have been updated and are now displayed in the mainnode, in the Reactions subnode, and in the Porous Media Diffusion subnode.
- The Reactions subnode now includes a Reacting Volume setting (Total volume or
Pore volume) for controlling the basis of the pellet reactions.
- The bed porosity is no longer defined in the Reactive Pellet Bed node. Instead,this value needs to be defined in a Porous Medium node or in an Unsaturated
Porous Medium node that solves for the transport in the bed pores. When none ofthe porous medium domain features are present, a warning node is shown in thesolver sequence when computing the model.
- When using multiple pellet sizes, the porosity for each pellet can be defined.
- When using multiple pellet sizes, the bed volume fraction of each size is given
instead of the volume percentage.
NEW REACTION NODE FUNCTIONALITY IN THE REACTION ENGINEERINGAND CHEMISTRY INTERFACES• It is now possible to balance the reaction formula. To do so, click the Balance buttonin the upper-right corner of the Reaction Formula section.
• The reaction rate is now by default defined from the Mass action law. This waspreviously referred to as the Automatic definition.
• The overall reaction orders when the Mass action law is used are now displayed intext form in the Reaction Rate section. The reaction order for both surface andvolumetric species are displayed.
• The overall forward reaction order and the overall reverse reaction order (whenpresent) are reported. For surface reactions, the reaction order for both surface andvolumetric species are reported.

CHEMICAL REACTION ENGINEERING MODULE|

61

AUTOMATIC DEFINITION OF THE MOLAR MASS IN THE REACTION
ENGINEERING INTERFACE AND THE CHEMISTRY INTERFACE• The molar mass is now automatically computed from the species chemical formula.
The species name is parsed for elements in the periodic table, and the molar mass iscomputed using the corresponding elemental masses.
- The molar mass is automatically defined when a Species node is created, as well as
when a species is added to a Species Group node.
- When the automatic calculation fails, for example, when a descriptive name suchas water is used, the molar mass is set to 0 g/mol.
- When computing a model that contains species for which the molar mass remains
at zero, a warning node is added in the solver sequence.
THE REACTION ENGINEERING INTERFACE• It is no longer necessary to use fully scoped variables when postprocessing
Reaction Engineering results in 0D components. For example, you can now plot areaction rate variable re.R_OH instead of using the fully scoped comp1.re.R_OH.
• The mass balance settings have been moved to the Reactor section in the interface
settings. The settings for the reactor volume and volumetric rate of change are now
given below the Reactor type setting. The Mass Balance section has been removed.
• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Reactor- Energy Balance- Mixture Properties- Species Matching (visible when Thermodynamics has been enabled)- Calculate Transport Properties- Equilibrium Species Vector (visible when equilibrium reactions are used)- Activity- CHEMKIN Import for Species Properties- Advanced Settings (visible when Advanced Physics Options is enabled)
Note that applications created in previous versions retain the original section order.
• Reaction rates for all species are now available as postprocessing variables.
• A new setting, Surface area to volume ratio, is now available when modeling surface
reactions.

62 |CHAPTER 1: RELEASE NOTES• When overconstrained equilibrium reactions occur, a Show Conflicts button is now
shown in the Equilibrium Species Vector section on the interface level. Clicking that
button, a message indicating the overconstrained reaction is shown.
• The mass conservation equation solved for is now shown when selecting a Species
node. The equation is updated in accordance with the reactor type used.
THE CHEMISTRY INTERFACE• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Model Input- Mixture Properties- Species Matching- Calculate Transport Properties- Activity- CHEMKIN Import for Species Transport- Extra Dimension
Note that applications created in previous versions retain the original section order.
• The mixture type (diluted species or concentrated species) is now controlled using
the Type list at the top of the Mixture Properties section. It was previously located in
the Species Matching section.
• The section Equilibrium Species Vector has been removed from the Settings
window of the interface.
• Thermodynamic properties are now always defined. The Calculate Thermodynamic
Properties section, with the corresponding check box, has been removed.
- The Species Thermodynamic Expressions section is always available in a Species
node.
- The Reaction Thermodynamic Properties section is always available in a Reaction orElectrode Reaction node.
• The Calculate mixture properties check box, in the Calculate Transport Properties
section, is now enabled by default.

CHEMICAL REACTION ENGINEERING MODULE|

63• The ratio of specific heats can now be specified in the Calculate Transport Properties
section. The ratio is defined and announced and can be used in other physics
interfaces.
• The setting to specify that the concentration, or activity, of species does not change
has been renamed. It is now called Constant concentration/activity. It waspreviously called Locked concentration/activity.
• The nomenclature in the tables in the Species Matching table section has been mademore distinct. Species can now be one of the following types; Constant, Variable,
Solvent, or Free species.
• The tables in the Species Matching section no longer contain a Reaction rate
column.
• The table at the top of the Species Matching table is now named Bulk species tocommunicate that these species are present in the mixture phase.
NEW FEATURES FOR POROUS MEDIA TRANSFER

Two new domain features, the Porous Medium and Unsaturated Porous Mediumfeatures are available in the Transport of Diluted Species in Porous Media andTransport of Diluted Species interfaces. The new features include support for using the
Porous Material node, also new in version 5.6, for assigning material properties to themultiple phases in a porous medium. The new features have subnodes to define phase
properties. The subnodes follow the same structure as the subnodes available for a
Porous Material.
The settings Dispersion and Volatilization in partially saturated porous media havebeen removed from the interface level of the Transport of Diluted Species in PorousMedia and Transport of Diluted Species interfaces. This functionality is now available
in the subnodes of the new features.
The new domain features replace the previously available Porous Media Transport
Properties and Partially Saturated Porous Media features. When opening a model
created in a previous version, the previous features are kept in the model.

New Applications in Version 5.6
HEAT PIPE WITH ACCURATE LIQUID AND GAS PROPERTIESHeat pipes are designed to transfer heat efficiently through vaporization, mass transfer,and condensation of a working fluid. They are found in a wide variety of applications

64 |CHAPTER 1: RELEASE NOTES

where thermal control is of importance, with cooling of electronics being a prominent
example.
Inside a heat pipe, the temperature difference between the hot and cold sides together
with the temperature dependence of the vapor pressure, induce a pressure difference
across the vapor chamber. The pressure difference, in turn, drives the vapor from the
hot to the cold side. The vaporization acts as a heat sink at the vapor–wick interface at
the hot side, and conversely, the condensation as a heat source, at the cold side. Thismodel demonstrates how the laminar flow in the vapor chamber of the heat pipe canbe coupled to the liquid phase transport through the porous wick, and how
thermodynamic properties of water can be obtained from the thermodynamics
database. The importance of vapor transport is compared to the conductive heattransfer in the pipe wall. The former dominates the latter by several orders ofmagnitude.
FERMENTATION IN BEER BREWING

During the beer fermentation process, alcohol, carbon dioxide, and various flavors areformed when sugars are consumed by yeast. In this example, the fermentation process
is first modeled in a perfectly mixed tank using the Reaction Engineering interface. In
the next step, a space-dependent tank model is set up, accounting for mass transfer,heat transfer, and natural convection.
The model in this example can be used to optimize the beer fermenting process andimprove the taste of your beer. The model allows you to study the effect of, forexample, initial sugar content, temperature, and yeast type on the fermentation
process.

Updated Applications in Version 5.6
IMPROVED MODELS

The following applications have been updated and significantly improved:• Analysis of NOx Reaction Kinetics• Chemical Reactions and Soot Build-Up in a Diesel Filter• Engine Coolant Properties, under Thermodynamics in the Application Library.
• Finding Kinetic Arrhenius Parameters Using Parameter Estimation• Hydrocarbon Dehalogenation in a Tortuous Microreactor• NOx Reduction in a Monolithic Reactor

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65

• Parameter Estimation for Nonideal Reactor Models• Steam Reformer
FULLY DEVELOPED FLOW

The following applications have been updated to use the fully developed flow at inlets:• Chemical Vapor Deposition of GaAs
• Dissociation in a Tubular Reactor• Fine Chemical Production in a Plate Reactor• Steam Reformer• Thermal Decomposition
AUTOMATIC DEFINITION OF MOLAR MASS

The following applications have been updated to use molar masses deduced from thespecies chemical formula:• Carbon Deposition in Heterogeneous Catalysis• Chemical Reactions and Soot Build-Up in a Diesel Filter• Packed Bed Reactor

Backward Compatibility with Version 5.4 and Earlier
SPECIFYING VOLUMETRIC FLOW RATE OF A PLUG FLOW REACTOR IN
REACTION ENGINEERING

When using the Reaction Engineering interface to model gas flow in a plug flow
reactor, you must now specify either the pressure or the volumetric flow rate, not both.
Running Java® files from previous versions may fail if the volumetric flow rate is set
while also prescribing the pressure. In this case, specify to instead compute the pressure
from the ideal gas law in the following manner:model.component("comp1").physics("re").prop("mixture").set("psource","idealGas");This selects Ideal gas law in the Reactor pressure list in the Mixture Properties section.
When this is done, the User defined option is available in the Volumetric rate list in theMass Balance section.

66 |CHAPTER 1: RELEASE NOTESWALL FUNCTION VARIABLES OMITTED IN LAMINAR REACTING FLOW

Dependent variables for the mass fraction wall functions are no longer added whenusing the Reacting Flow multiphysics interface for laminar flow. Due to the nowomitted variables, running Java® files from previous versions may fail during the solver
sequence generation.
When specifying the content of a segregated group in the manner ofmodel.sol("sol1").feature("s1").feature("se1").feature("ss1").set("segvar", new String[]{"comp1_w1", "comp1_w2", "comp1_tcs_wWall_w1","comp1_tcs_wWall_w2"});

remove entries for the wall functions variables of the kind comp1_tcs_wWall_name toresult inmodel.sol("sol1").feature("s1").feature("se1").feature("ss1").set("segvar", new String[]{"comp1_w1", "comp1_w2"});

Backward Compatibility with Version 5.3a and Earlier
NO FLUX FORMULATION

The formulation of the No Flux feature has been changed in the Transport of Diluted
Species interface in version 5.4 so that the flux relative to the convective flux is set tozero. The new formulation is used when opening a model from a previous session. In
the previous formulation, the total flux was set to zero.
Affected interfaces: Transport of Diluted Species, Transport of Diluted Species in
Porous Media, Transport of Concentrated Species, Nernst-Planck Equations, andElectrophoretic Transport.

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67

Composite Materials Module
New Functionality in Version 5.6
POROELASTICITY, LAYERED SHELL MULTIPHYSICS INTERFACEThe new Poroelasticity, Layered Shell multiphysics interface is intended for modeling
Darcy’s law coupled with structural layered shells. This interface will add Layered Shell
and Layered Darcy’s Law interfaces, together with the new Layered Poroelasticity
multiphysics coupling. This new multiphysics interface allows the modeling ofmultilayer domains, such as paperboard and composites having different material
properties per layer.
The Layered Darcy’s Law interface requires the Porous Media Flow Module.
PLY-BASED MODELING APPROACH

Support for the ply-based modeling has been added in order to define complex layups
much easier compared to the zone-based modeling approach. This is achieved byadding a Selection option on the Layered Material Link, Layered Material, Single Layer
Material nodes under Layered Material Stack.
If the selection of all subnodes representing different plies is the same as that of aparent node, no zones are created. If the subnodes (or plies) are assigned different
selections, the Layered Material Stack automatically creates zones, and the information
about each zone is displayed in the Stack Zone Definition table. Each zone is treated asa different layered material and can be used accordingly in the physics and the
postprocessing.
You can also create Layer Cross Section Preview plots and Create Layer Cross Section Plotfrom all layered materials and layered features.
PERFORMANCE IMPROVEMENT IN THE FSDT SHELL

The performance of FSDT shells, implemented in the Layered Linear Elastic Material of
the Shell interface, is improved significantly for some simpler use cases. This is achievedby integrating the energy expressions only on the base surface using NMQ formulation
instead of integrating energy expressions in the product geometry. The new
formulation is quite useful in composite sizing problems and is used automatically,

68 |CHAPTER 1: RELEASE NOTES

except in the following cases, where energy expressions are integrated on the productgeometry:• If there is any subnode present• If there is any layered multiphysics coupling present• If out-of-plane strain DOF is present• If mixed formulation DOF is present
CONNECTION TYPE OPTION IN THE LAYERED MATERIAL CONTINUITY

A new option of Connection type has been added in the Continuity node in the Layered
Shell interface. The new option is available with Advanced Physics Options enabled. The
two choices in the connection type input are Straight and Twisted. The twisted
connection type connects the two layered materials meeting side by side in reversedorder by connecting the top of one layered material to the bottom of the other layeredmaterial. The twisted connection is particularly useful when the normal vector is
flipped on one of the sides.
CHANGE IN DEFAULT SOLID MODEL IN THE LAYERED SHELL INTERFACE

The default Solid model of the Linear Elastic Material in the Layered Shell interface isswitched from isotropic to orthotropic. The orthotropic solid model seems like a morenatural choice for composite materials. In case any isotropic material is used from thelibrary, its equivalent orthotropic properties are automatically computed using theelastic properties synchronization functionality.
LAYERED MATERIAL PREVIEW PLOTS IN AN APPLICATION

Support for including layered material preview plots in an application has been added.
This is achieved by adding a support for creating a preview plot in the postprocessing.
The two new buttons, Create Layer Cross Section Plot and Create Layer Stack Plot, areadded on different layered material nodes for this purpose. In addition to using it inan application, the new functionality can also be used for storing different preview
plots in the model.
DAMAGE IN LAYERED SHELLSAll the Damage models available in the Solid Mechanics interface are now available in
Layered Linear Elastic Material in the Shell interface, and to the Linear Elastic Material
model in the Layered Shell interface.
The Damage feature requires the Nonlinear Structural Materials Module.

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69

LAYERED HYPERELASTIC MATERIAL IN THE SHELL INTERFACE

All the Hyperelastic Material models available in the Solid Mechanics interface are now
available in the Layered Hyperelastic Material node in the Shell interface. If theComposite Materials Module is available, the material models can also be used in
multilayered shells, and the individual layers can have different material models.
The Hyperelastic Material feature requires the Nonlinear Structural Materials Module.
LARGE STRAIN PLASTICITY IN THE LAYERED SHELL INTERFACEThe Linear Elastic Material in the Layered Shell interface now includes the possibility tomodel Large Strain Plasticity. The same set of yield functions and isotropic hardening
models as in the Solid Mechanics interface are available. The formulation assumes large
plastic strains, which gives a good approximation above 10% strain.
It is now possible to add Plasticity to the Hyperelastic Material in the Layered Shellinterface. The new subnode uses the Large Strain Plasticity formulation. The same setof yield functions and isotropic hardening models as in Hyperelastic Material models for
the Solid Mechanics interface are available.
The Plasticity feature requires the Nonlinear Structural Materials Module.
SET VARIABLES NODE UNDER PLASTICITY

A new subnode Set Variables is added on the Plasticity node, which is available underLinear Elastic Material in the Layered Shell interface and Layered Linear Elastic Materialin Shell and Membrane interfaces. The purpose of this node is to reset plastic DOFs tomodel cases like stress relieving and annealing.
The Plasticity feature requires the Nonlinear Structural Materials Module.
MIXED FORMULATION IN LAYERED LINEAR ELASTIC MATERIALIn Layered Linear Elastic Material in the Shell interface, a mixed formulation has been
added. Mixed formulations can improve accuracy for materials with low
compressibility.
VISCOUS DAMPING IN LAYERED LINEAR ELASTIC MATERIAL

The possibility to add viscous damping has been added to the Damping subnode under
the Layered Linear Elastic Material in the Shell interface.
PORE PRESSURE OPTION IN EXTERNAL STRESSIn the External Stress subnode of Linear Elastic Material in the Layered Shell interface,a new option of Pore Pressure has been added.

70 |CHAPTER 1: RELEASE NOTESMISCELLANEOUS• Improvements and corrections in handling variable thickness layers in the Layered
Shell, Shell, and Membrane interfaces.
• Improvements and corrections in computing total reaction forces and moments in
the Layered Shell interface.
• Default continuity is imposed on the common edges of Rigid Domain and Layered
Linear Elastic Material (or similar) in the Shell interface.
• New operator xdintopallint has been added for integrating a quantity in all
interfaces of all the layered materials.
• Support for slitting the DOFs in the extra dimension with partial base surface
selection has been added. This allows the Delamination node to be available on only
a few interfaces with the partial base surface selection.
• The default plots for Layered Linear Elastic Material in the Shell and Membraneinterfaces have been improved.

New Models in Version 5.6
PLY DROP-OFF IN A COMPOSITE PANEL

Ply drop-off often occurs in composite laminates to tailor the laminate thickness basedon the loading requirements. This example illustrates the modeling of ply drop-off in
a composite panel. The panel considered for the analysis has symmetric angle-ply layupwith three sections: thick, taper, and thin. The thick section has sixteen plies divided
into the core, top-bottom belts, and dropped plies. Out of sixteen plies in the thicksection, eight plies are dropped gradually in the taper section with specified stagger
distance. The layerwise-theory-based approach, together with the Stack Zone
modeling and variable thickness layer functionality, is used for the detailed
representation of the ply drop scenario. A stationary analysis is performed to compute
stresses in different plies of various sections of the composite panel under the appliedexternal load.
STACKING SEQUENCE OPTIMIZATIONThis example illustrates the optimization of the stacking sequence in a composite
laminate. The composite laminate considered for the analysis has six layers withsymmetric layup. The Carbon-Epoxy material having orthotropic material properties
is used as a lamina material. The optimization analysis is performed to find the
optimum fiber orientation in each layer under specified loading conditions with anobjective of minimizing the maximum stress value in the laminate. The layup is

COMPOSITE MATERIALS MODULE|

71

assumed symmetric, thus three ply angles are the control variables and the BOBYQA
optimization method is applied to find the optimum stacking sequence.
HEATING CIRCUIT: LAYERED SHELL VERSIONThis multiphysics example simulates the electrical heat generation, heat transfer, andmechanical stresses and deformations of a heating circuit device. The model uses theHeat Transfer in Shells interface of the Heat Transfer Module in combination with theElectric Currents, Layered Shell interface from the AC/DC Module and the Layered
Shell interface from the Composite Materials Module.

72 |CHAPTER 1: RELEASE NOTESC o r r o s i o n M o du l e
New Functionality in Version 5.6• A new Corrosion Material Library has been added.
• A new Phase Field interface has been added.
ELECTROCHEMISTRY INTERFACES• A Dissolving-Depositing Species section has been added to the Separator node of the
Tertiary Current Distribution, Nernst–Planck interface.
• The stoichiometric coefficients for the dissolving-depositing species table are now
reset to the default value of 0 when duplicated.
• The Electrode Reaction and Porous Electrode Reaction nodes of the Tertiary Current
Distribution, Nernst–Planck interface now include a new option for linearization ofconcentration dependence for low concentrations of Butler–Volmer kinetics
expression type when using either a mass action law or lumped multistep as theexchange current density type.
• A new From material option has been added for the Local current density setting in
the Electrode Kinetics section in electrode reactions of all electrochemistryinterfaces.
• A new property, Physics vs. Materials Reference Electrode Potential, has been added
to all electrochemistry interfaces.
• The solver defaults have been updated for most Electrochemistry interfaces.
Geometric and algebraic multigrid solvers (GMG and AMG) are now automaticallygenerated by the study step nodes. A direct solver will, however, still always be usedby default. Minor changes have also been made to default scales and tolerances.
• The Electrode Surface (eebii) boundary feature, applicable to both exterior andinterior boundaries of electrolyte domains, is now obsolete. It is replaced with a new
Electrode Surface (es) boundary feature, applicable to exterior boundaries only, anda new Perforated Electrode Surface (pes) boundary feature, applicable to interior
boundaries of electrolyte domains only.
• The Thin Electrolyte Layer boundary feature is now available for the Electroanalysis
charge conservation model in the Tertiary Current Distribution interface.

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73

• A new Highly Conductive Porous Electrode domain node has been added to thePrimary/Secondary/Tertiary Current Distribution, Lithium-Ion Battery, andBattery with Binary Electrolyte interfaces.
• The irreversible heat source term now contains a contribution from the film
resistance resistive heating.
CHEMICAL SPECIES TRANSPORT INTERFACES• It is now straightforward to apply diffusion coefficients defined by a Chemistryinterface. The input for diffusion coefficients now includes a Source list with theoptions Material and Chemistry. Selecting the latter, it is then possible to pick up
coefficients from any Chemistry interface present in the model.
• The total number of constraints applied on a boundary are now analyzed. When
combining concentration constraints with equilibrium reactions on boundaries, awarning is shown when the system is overconstrained. The constraint analysis isperformed in the following interfaces: Transport of Diluted Species and Transportof Concentrated Species.
• When solving mass transfer problems, iterative algebraic multigrid (AMG) solvers
are now automatically generated in the solver sequences for large models. A direct
solver is also added for convenience.
THE CHEMISTRY INTERFACE• It is now possible to balance the reaction formula. To do so, click the Balance buttonin the upper-right corner of the Reaction Formula section.
• The reaction rate is now by default defined from the Mass action law. This waspreviously referred to as the Automatic definition.
• The overall reaction orders when the Mass action law is used are now displayed intext form in the Reaction Rate section. The reaction order for both surface andvolumetric species are displayed.
• The overall forward reaction order and the overall reverse reaction order (whenpresent) are reported. For surface reactions, the reaction order for both surface andvolumetric species are reported.

74 |CHAPTER 1: RELEASE NOTES• The molar mass is now automatically computed from the species chemical formula.
The species name is parsed for elements in the periodic table, and the molar mass iscomputed using the corresponding elemental masses.
- The molar mass is automatically defined when a Species node is created, as well as
when a species is added to a Species Group node.
- When the automatic calculation fails, for example, when descriptive name such as
water is used, the molar mass is set to 0 g/mol.
- When computing a model that contains species for which the molar mass remains
at zero, a warning node is added in the solver sequence.
• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Model Input- Mixture Properties- Species Matching- Calculate Transport Properties- Activity- Extra Dimension
Note that applications created in previous versions retain the original section order.
• The mixture type (diluted species or concentrated species) is now controlled using
the Type list at the top of the Mixture Properties section. It was previously located in
the Species Matching section.
• The Equilibrium Species Vector sector has been removed from the settings windowof the interface.
• Thermodynamic properties are now always defined. The Calculate Thermodynamic
Properties section, with the corresponding check box, has been removed.
- The Species Thermodynamic Expressions section is always available in a Species
node.
- The Reaction Thermodynamic Properties section is always available in a Reaction orElectrode Reaction node.
• The Calculate mixture properties check box, in the Calculate Transport Properties
section, is now enabled by default.

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75

• The ratio of specific heats can now be specified in the Calculate Transport Properties
section. The ratio is defined and announced and can be used in other physics
interfaces.
• The setting to specify that the concentration, or activity, of species does not change
has been renamed. It is now called Constant concentration/activity. It waspreviously called Locked concentration/activity.
• The nomenclature in the tables in the Species Matching table section has been mademore distinct. Species can now be one of the following types: Constant, Variable,
Solvent, or Free species.
• The tables in the Species Matching section no longer contain a Reaction rate
column.
• The table at the top of the Species Matching table is now named Bulk species tocommunicate that these species are present in the mixture phase.
NEW FEATURES FOR POROUS MEDIA TRANSFER

Two new domain features, the Porous Medium and Unsaturated Porous Mediumfeatures, are now available in the Transport of Diluted Species in Porous Media andTransport of Diluted Species interfaces. The new features include support for using the
Porous Material node, also new in version 5.6, for assigning material properties to themultiple phases in a porous medium. The new features have subnodes to define phase
properties. The subnodes follow the same structure as the subnodes available for a
Porous Material.
The Dispersion and Volatilization settings in partially saturated porous media havebeen removed from the interface level of the Transport of Diluted Species in PorousMedia and Transport of Diluted Species interfaces. This functionality is now available
in the subnodes of the new features.
The new domain features replace the previously available Porous Media Transport
Properties and Partially Saturated Porous Media features. When opening a model
created in a previous version, the previous features are kept in the model.

New and Updated Models in Version 5.6• The Localized Corrosion Using the Level Set Method model has been updated byevaluating the local current density expression only in the microstructure domain.
• A new Localized Corrosion Using the Phase Field Method tutorial model is now
available.

76 |CHAPTER 1: RELEASE NOTES• The following updated models use the new Corrosion Material library:crevice_corrosion_fe, crevice_corrosion_with_deformation,
galvanic_corrosion_mg_alloys, galvanic_corrosion_with_deformation, isolator
thickness, ship_hull, stray_current, atmospheric_corrosion, andunder_deposit_corrosion.
• The Crevice Corrosion in Iron in an Acetic Acid/Sodium Acetate Solution model
has been updated to use the Highly Conductive Porous Electrode domain node.

Backward Compatibility with 5.4• Default stoichiometric number for Dissolving-Depositing species changed to 0
(from 1). Java API backward compatibility may be affected.
• The Tertiary Current Distribution, Nernst Planck interfaces have changed default
settings to use the Nernst equation for equilibrium potential, Butler-Volmer for
kinetics expression type, and Mass action law for exchange current density type. JavaAPI backward compatibility may be affected.

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ECAD Import Module
New Functionality in Version 5.6
The ECAD Import Module brings a significant performance improvement for theimport of copper layers from IPC-2581 and ODB++ files. Large copper layers may
import several times faster when compared to previous versions.

Backward Compatibility with Version 5.3a
The elevation property of the Import function is now also initialized when setting
the manualelevation property to off. Previously, it was only initialized when setting
the filename property, the manualelevation property is off, and the value of either
the height or importtype properties is changed.

78 |CHAPTER 1: RELEASE NOTESElectrochemistry Module
New Functionality in Version 5.6
ELECTROCHEMISTRY INTERFACES• For the Electrode Reaction and Porous Electrode Reaction nodes of the Tertiary
Current Distribution, Nernst–Planck interface, a new option for the linearization ofconcentration dependence for low concentrations of the Butler–Volmer kinetics
expression type is now available when using either mass action law or lumped
multistep as the exchange current density type.
• A new From material option has been added for the Local current density setting in
the Electrode Kinetics section in electrode reactions of all electrochemistryinterfaces.
• A new property, Physics vs. Materials Reference Electrode Potential, has been added
to all electrochemistry interfaces.
• The solver defaults have been updated for most Electrochemistry interfaces.
Geometric and algebraic multigrid solvers (GMG and AMG) are now automaticallygenerated by the study step nodes. A direct solver will, however, still always be usedby default. Minor changes have also been made to default scales and tolerances.
• The Electrode Surface (eebii) boundary feature, applicable to both exterior andinterior boundaries of electrolyte domains, is now obsolete. It is replaced with a new
Electrode Surface (es) boundary feature, applicable to exterior boundaries only, anda new Perforated Electrode Surface (pes) boundary feature, applicable to interior
boundaries of electrolyte domains only.
• The Thin Electrolyte Layer boundary feature is now available for the Electroanalysis
charge conservation model in the Tertiary Current Distribution interface.
• A new Highly Conductive Porous Electrode domain node has been added to thePrimary/Secondary/Tertiary Current Distribution, Lithium-Ion Battery, andBattery with Binary Electrolyte interfaces.
• The irreversible heat source term now contains a contribution from the film
resistance resistive heating.
CHEMICAL SPECIES TRANSPORT INTERFACES• It is now straightforward to apply diffusion coefficients defined by a Chemistryinterface. The input for diffusion coefficients now includes a Source list with the

ELECTROCHEMISTRY MODULE|

79

options Material and Chemistry. When selecting the latter, it is then possible to pickup coefficients from any Chemistry interface present in the model.
• The total number of constraints applied on a boundary are now analyzed. When
combining concentration constraints with equilibrium reactions on boundaries, awarning is shown when the system is overconstrained. The constraint analysis isperformed in the following interfaces: Transport of Diluted Species and Transportof Concentrated Species.
• When solving mass transfer problems, iterative algebraic multigrid (AMG) solvers
are now automatically generated in the solver sequences for large models. A direct
solver is also added for convenience.
THE CHEMISTRY INTERFACE• It is now possible to balance the reaction formula. To do so, click the Balance buttonin the upper-right corner of the Reaction Formula section.
• The reaction rate is now by default defined from the Mass action law. This waspreviously referred to as the Automatic definition.
• The overall reaction orders when the Mass action law is used are now displayed intext form in the Reaction Rate section. The reaction order for both surface andvolumetric species are displayed.
• The overall forward reaction order and the overall reverse reaction order (whenpresent) are reported. For surface reactions, the reaction order for both surface andvolumetric species are reported.
• The molar mass is now automatically computed from the species chemical formula.
The species name is parsed for elements in the periodic table, and the molar mass iscomputed using the corresponding elemental masses.
- The molar mass is automatically defined when a Species node is created, as well as
when a species is added to a Species Group node.
- When the automatic calculation fails, for example, when descriptive name such as
water is used, the molar mass is set to 0 g/mol.
- When computing a model that contains species for which the molar mass remains
at zero, a warning node is added in the solver sequence.

80 |CHAPTER 1: RELEASE NOTES• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Model Input- Mixture Properties- Species Matching- Calculate Transport Properties- Activity- Extra Dimension
Note that applications created in previous versions retain the original section order.
• The mixture type (diluted species or concentrated species) is now controlled using
the Type list at the top of the Mixture Properties section. It was previously located in
the Species Matching section.
• The Equilibrium Species Vector section has been removed from the settings windowof the interface• Thermodynamic properties are now always defined. The Calculate Thermodynamic
Properties section, with the corresponding check box, has been removed.
- The Species Thermodynamic Expressions section is always available in a Species
node.
- The Reaction Thermodynamic Properties section is always available in a Reaction orElectrode Reaction node.
• The Calculate mixture properties check box in the Calculate Transport Properties
section is now enabled by default.
• The ratio of specific heats can now be specified in the Calculate Transport Properties
section. The ratio is defined and announced and can be used in other physics
interfaces.
• The setting to specify that the concentration, or activity, of species does not change
has been renamed. It is now called Constant concentration/activity. It waspreviously called Locked concentration/activity.
• The nomenclature in the tables in the Species Matching table section has been mademore distinct. Species can now be one of the following types: Constant, Variable,
Solvent, or Free species.
• The tables in the Species Matching section no longer contain a Reaction rate
column.

ELECTROCHEMISTRY MODULE|

81

• The table at the top of the Species Matching table is now named Bulk species tocommunicate that these species are present in the mixture phase.
NEW FEATURES FOR POROUS MEDIA TRANSFER

Two new domain features, the Porous Medium and Unsaturated Porous Mediumfeatures, are now available in the Transport of Diluted Species in Porous Media andTransport of Diluted Species interfaces. The new features include support for using the
Porous Material node, also new in version 5.6, for assigning material properties to themultiple phases in a porous medium. The new features have subnodes to define phase
properties. The subnodes follow the same structure as the subnodes available for a
Porous Material.
The settings Dispersion and Volatilization in partially saturated porous media havebeen removed from the interface level of the Transport of Diluted Species in PorousMedia and Transport of Diluted Species interfaces. This functionality is now available
in the subnodes of the new features.
The new domain features replace the previously available Porous Media Transport
Properties and Partially Saturated Porous Media features. When opening a model
created in a previous version, the previous features are kept in the model.

Backward Compatibility with Version 5.4• The Tertiary Current Distribution, Nernst–Planck interfaces have changed default
settings to use the Nernst equation for equilibrium potential, Butler-Volmer for
kinetics expression type, and Mass action law for exchange current density type. JavaAPI backward compatibility may be affected.

82 |CHAPTER 1: RELEASE NOTESE le c tr o de po s i t i on Mod u l e
New Functionality in Version 5.6
GENERAL NEW FUNCTIONALITY

A new Phase Field interface has been added.
ELECTROCHEMISTRY INTERFACES• A Dissolving-Depositing Species section has been added to the Separator node of the
Tertiary Current Distribution, Nernst–Planck interface.
• The stoichiometric coefficients for the dissolving-depositing species table are now
reset to the default value of 0 when duplicated.
• For the Electrode Reaction and Porous Electrode Reaction nodes of the Tertiary
Current Distribution, Nernst–Planck interface, a new option for the linearization ofconcentration dependence for low concentrations of the Butler–Volmer kinetics
expression type is now available when using either mass action law or lumped
multistep as the exchange current density type.
• A new From material option has been added for the Local current density setting in
the Electrode Kinetics section in electrode reactions of all electrochemistryinterfaces.
• A new property, Physics vs. Materials Reference Electrode Potential, has been added
to all electrochemistry interfaces.
• The solver defaults have been updated for most Electrochemistry interfaces.
Geometric and algebraic multigrid solvers (GMG and AMG) are now automaticallygenerated by the study step nodes. A direct solver will, however, still always be usedby default. Minor changes have also been made to default scales and tolerances.
• The Electrode Surface (eebii) boundary feature, applicable to both exterior andinterior boundaries of electrolyte domains, is now obsolete. It is replaced with a new
Electrode Surface (es) boundary feature, applicable to exterior boundaries only, anda new Perforated Electrode Surface (pes) boundary feature, applicable to interior
boundaries of electrolyte domains only.
• The Thin Electrolyte Layer boundary feature is now available for the Electroanalysis
charge conservation model in the Tertiary Current Distribution interface.

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• A new Highly Conductive Porous Electrode domain node has been added to thePrimary/Secondary/Tertiary Current Distribution, Lithium-Ion Battery, andBattery with Binary Electrolyte interfaces.
• The irreversible heat source term now contains a contribution from the film
resistance resistive heating.
CHEMICAL SPECIES TRANSPORT INTERFACES• It is now straightforward to apply diffusion coefficients defined by a Chemistryinterface. The input for diffusion coefficients now includes a Source list with theoptions Material and Chemistry. Selecting the latter it is possible to pick up
coefficients from any Chemistry interface present in the model.
• The total number of constraints applied on a boundary are now analyzed. When
combining concentration constraints with equilibrium reactions on boundaries, awarning is shown when the system is overconstrained. The constraint analysis isperformed in the following interfaces: Transport of Diluted Species and Transportof Concentrated Species.
• When solving mass transfer problems, iterative algebraic multigrid (AMG) solvers
are now automatically generated in the solver sequences for large models. A direct
solver is also added for convenience.
THE CHEMISTRY INTERFACE• It is now possible to balance the reaction formula. To do so, click the Balance buttonin the upper-right corner of the Reaction Formula section.
• The reaction rate is now by default defined from the Mass action law. This waspreviously referred to as the Automatic definition.
• The overall reaction orders when the Mass action law is used are now displayed intext form in the Reaction Rate section. The reaction order for both surface andvolumetric species are displayed.
• The overall forward reaction order and the overall reverse reaction order (whenpresent) are reported. For surface reactions, the reaction order for both surface andvolumetric species are reported.

84 |CHAPTER 1: RELEASE NOTES• The molar mass is now automatically computed from the species chemical formula.
The species name is parsed for elements in the periodic table, and the molar mass iscomputed using the corresponding elemental masses.
- The molar mass is automatically defined when a Species node is created, as well as
when a species is added to a Species Group node.
- When the automatic calculation fails, for example, when descriptive name such as
water is used, the molar mass is set to 0 g/mol.
- When computing a model that contains species for which the molar mass remains
at zero, a warning node is added in the solver sequence.
• The order of the sections in the Settings window has been changed to reflect theirrelative importance. The new order, from top to bottom, is:- Model Input- Mixture Properties- Species Matching- Calculate Transport Properties- Activity- Extra Dimension
Note that applications created in previous versions retain the original section order.
• The mixture type (diluted species or concentrated species) is now controlled using
the Type list at the top of the Mixture Properties section. It was previously located in
the Species Matching section.
• The section Equilibrium Species Vector has been removed from the Settings
window of the interface.
• Thermodynamic properties are now always defined. The Calculate Thermodynamic
Properties section, with the corresponding check box, has been removed.
- The Species Thermodynamic Expressions section is always available in a Species
node.
- The Reaction Thermodynamic Properties section is always available in a Reaction orElectrode Reaction node.
• The Calculate mixture properties check box in the Calculate Transport Properties
section is now enabled by default.

ELECTRODEPOSITION MODULE|

85• The ratio of specific heats can now be specified in the Calculate Transport Properties
section. The ratio is defined and announced and can be used in other physics
interfaces.
• The setting to specify that the concentration, or activity, of species does not change
has been renamed. It is now called Constant concentration/activity. It waspreviously called Locked concentration/activity.
• The nomenclature in the tables in the Species Matching table section has been mademore distinct. Species can now be one of the following types: Constant, Variable,
Solvent, or Free species.
• The tables in the Species Matching section no longer contain a Reaction rate
column.
• The table at the top of the Species Matching table is now named Bulk species tocommunicate that these species are present in the mixture phase.
NEW FEATURES FOR POROUS MEDIA TRANSFER

Two new domain features, the Porous Medium and Unsaturated Porous Mediumfeatures, are now available in the Transport of Diluted Species in Porous Media andTransport of Diluted Species interfaces. The new features include support for using the
Porous Material node, also new in version 5.6, for assigning material properties to themultiple phases in a porous medium. The new features have subnodes to define phase
properties. The subnodes follow the same structure as the subnodes available for a
Porous Material.
The settings Dispersion and Volatilization in partially saturated porous media havebeen removed from the interface level of the Transport of Diluted Species in PorousMedia and Transport of Diluted Species interfaces. This functionality is now available
in the subnodes of the new features.
The new domain features replace the previously available Porous Media Transport
Properties and Partially Saturated Porous Media features. When opening a model
created in a previous version, the previous features are kept in the model.

New and Updated Models in Version 5.6• The Electroplating of Multiple Components in a Rack model has been updated bysolving for charge transport only in the electroplating bath, excluding pump coverdomains.

86 |CHAPTER 1: RELEASE NOTES• A new Copper Deposition in a Trench Using the Phase Field Method tutorial model
is now available.
• The Copper Deposition in a Trench Using the Level Set Method model has been
updated to use the Highly Conductive Porous Electrode feature.

Backward Compatibility with Version 5.4• The default stoichiometric number for Dissolving-Depositing species changed to 0
(from 1). Java API backward compatibility may be affected.
• The Tertiary Current Distribution, Nernst Planck interfaces have changed default
settings to use the Nernst equation for equilibrium potential, Butler-Volmer for
kinetics expression type, and Mass action law for exchange current density type. JavaAPI backward compatibility may be affected.

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87

Fatigue Module
New Functionality in Version 5.6
FATIGUE COMPUTATIONS IN GEOMETRICALLY NONLINEAR PROBLEMSIn the Fatigue study step, the Include geometric nonlinearity option has been added.
This makes it possible to set up fatigue computations for problems with geometric
nonlinearities, such as large rotations.

88 |CHAPTER 1: RELEASE NOTESGeomechanics Module
New Functionality in Version 5.6
PLASTICITY IMPROVEMENTS

A new subnode, called Set Variables, has been added under Plasticity, Soil Plasticity,
Concrete, Rocks, and Elastoplastic Soil Material nodes. These new nodes make it possible
to reset plastic variables based upon boolean conditions, for both small-strain andlarge-strain plasticity options.
INPUT OF IN-SITU STRESS

A new option to enter In-situ stress is available in the External Stress subnode for the
Linear Elastic Material, Nonlinear Elastic Material, and Elastoplastic Soil Material models.
ELLIPTICAL CAP IMPROVEMENT

In the Soil Plasticity node, the transition zone between the elliptical cap and Mohr–
Coulomb or Drucker–Prager yield surfaces is modified to account for a smoothinterval.
MODIFICATIONS TO ELASTOPLASTIC SOIL MODELSFor the Extended Barcelona Basic soil model, Poisson’s ratio is a new input besides theshear modulus.
The initial void ratio is added as a material input for the Modified Cam-Clay, Modified
Structured Cam-Clay, and Extended Barcelona Basic soil models.
For the Hardening Soil model, the input for the void ratio at reference pressure is
replaced by the initial void ratio.
DEFAULT CONTOUR PLOTS FOR NONLINEAR MATERIAL MODELS

When using the Elastoplastic Soil Material in the Solid Mechanics interface, default
contour plots of the equivalent plastic strain are created inside stress plot groups.
Additionally, a separate contour plot showing the void ratio has been added.

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New Models in Version 5.6
BRITTLE FRACTURE OF A HOLED PLATE

In this example, the brittle fracture of a holed plate with a notch is modeled using aphase field damage model. The geometry of the plate is set up so that a mixed-mode
fracture is induced. The dimensions and material properties of the plate are taken fromexperimental data. The example shows how to set up an efficient and stable solver
configuration for this kind of problem.
MECHANICAL MODELING OF BENTONITE CLAY

In this example, the Extended Barcelona Basic Model (BBMx) is used to model
oedometer, uniaxial swelling, triaxial, and constrained swelling tests on bentonite clays
in order to recover the hydromechanical characteristics of the soil samples.
There is a good qualitative agreement between the simulations and the experimental
results used to validate the implementation of the BBMx soil model.
STRENGTH REDUCTION METHOD FOR SLOPE STABILITY

The strength reduction technique is a tool to find the factor of safety (FOS) in
geotechnical problems, particularly in slope stability. To determine the factor of safetyof the slope, the strength properties of the Mohr–Coulomb model are gradually
reduced until the failure occurs. The effect of nonassociative plasticity is demonstrated
for a range of friction angles.
SHALLOW FOUNDATION ON UNSATURATED SOIL

In this example, a settlement and heave analysis of a shallow foundation resting on an
unsaturated soil stratum is investigated with the Modified Cam-Clay and Extended
Barcelona Basic soil models. The effect of pore suction due to movements in thephreatic line and the resulting settlement and heave on the clay stratum are shown.

90 |CHAPTER 1: RELEASE NOTESH e a t T r a ns f e r Mod u l e
New and Improved Functionality in Version 5.6
PHASE CHANGE INTERFACE BOUNDARY CONDITION

The new Phase Change Interface feature is now available to capture the position of aphase change interface between two solids, two fluids, two porous media, or between
a solid and a fluid. The Stefan condition sets the temperature at the interface anddefines the front velocity from the heat transfer properties across the interface. Used
together with a Deforming Domain node, this method provides an accurate computationof the phase change front when no topology changes are expected for the interface.
See the Tin Melting Front tutorial for an example that uses this feature.
SEMITRANSPARENT SURFACE FOR RADIATION IN PARTICIPATING MEDIAThe new Semitransparent Surface feature is available in the Radiation in Participating
Media interface. On exterior boundaries, it allows users to specify an external radiation
intensity and to account for the part of this incoming intensity that is diffusivelytransmitted through the surface, along with the intensities emitted, reflected, andspecularly transmitted by the surface. On interior boundaries, the radiation intensities
upside and downside the surface are considered instead. It should be used instead of
the Opaque Surface feature when modeling semitransparent surfaces.
DIRECTIONAL DEPENDENT SURFACE PROPERTIES FOR SURFACE-TOSURFACE RADIATION

It is now possible to define a directional dependence for the surface material properties
in the Opaque Surface and Semitransparent Surface features of the Surface-to-Surface
Radiation interface. The Polar or Polar and Azimuthal options of the Directional
dependence list make it possible to set functions of the polar and azimuthal angles tobe used in the definition of the surface emissivity and transmissivity. Any analytical,
interpolation, or piecewise function with one argument, already defined in thecomponent, may be selected when the Polar option is selected. For the Polar and
Azimuthal option, you can select among the analytical and interpolation functions with
two arguments. Other dependencies, such as on temperature, can also be defined in
the Surface emissivity and Surface transmissivity user inputs.

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VIEW FACTORS UPDATE FOR SURFACE-TO-SURFACE RADIATIONThe option to control the view factor update for time-dependent simulations is now
available for Hemicube and Direct area integration methods. The View Factors Update
section is available with the Advanced Physics Options in the Surface-to-Surface
Radiation interface. In this section, you can define a criterion based on a user-defined
Expression. Doing so may considerably reduce the computation time of timedependent simulations.
NEW MATERIAL AND FEATURES FOR POROUS MEDIUM MODELSIn order to achieve a better clarity and usability of the user interface, the Porous Mediumfeature is now always available without having to select, at the interface level, the Heattransfer in porous media check box, which has been removed.
The Porous Medium feature itself has been refactored. Each phase is now handled in
dedicated subfeatures, namely Porous Matrix and Fluid. The effective material
properties are handled by the Porous Medium node, whereas the solid properties aredefined in the Porous Matrix subnode, and the fluid properties and velocity field aredefined in the Fluid node. It is also possible to account for an additional fluid phase,provided that this phase is immobile, by adding an Immobile Fluids subnode under the
Porous Medium feature. The Geothermal Heating, Thermal Dispersion, and Optically Thick
Participating Medium subnodes remain available under the Porous Medium feature.
However, the Pressure Work, Viscous Dissipation, and Phase Change Material subfeatures
are now available as subnodes of the Fluid subnode, as they affect the fluid variables inparticular.
In the user interface of the Porous Matrix subfeature, the settings have been
homogenized with those of the porous media features in the fluid flow and chemical
species transport interfaces. In particular, the Porosity is specified instead of the Volume
fraction of the solid phase. In addition, it is possible to set either the Dry bulk properties(which are measured including the empty pores) or the Solid phase properties,
depending on the availability of these measurements.
Using this new design, you can take advantage of the new Porous Material functionality
under the Materials node, in which the porosity and volume fractions can be set, andunder which the material properties are set in subnodes dedicated to each phase: Solid,
Fluid, and Immobile Fluid.
HEAT AND MOISTURE TRANSPORT IN POROUS MEDIA

A set of new interfaces and features is available for modeling coupled heat and moisturetransport in porous media filled with moist air and liquid water. They complete the92 |CHAPTER 1: RELEASE NOTES

features already available in version 5.5 for the modeling of heat and moisturetransport in moist air and building materials.
Moisture transport in porous media, by vapor convection and diffusion, and liquidwater convection and capillary flow, is handled by the new Moisture Transport in
Porous Media interface, which adds the Hygroscopic Porous Medium node as the default
model. It extends the capabilities of the Building Material node by modeling convection
in both phases due to total pressure variations, by modeling the liquid capillary flux
either with a Darcy’s Law or a diffusion model, and by adding support for gravity force
handling. This new formulation is more generic than the Building Material formulation,and should be applied for porous media staying in the hygroscopic region regarding
their amount of moisture. This new version of the Moisture Transport interface
benefits from the features already available for moisture transport in building materials
and moist air (Moisture Flux, Moisture Content, Outflow, and so on).
The new Moist Porous Media version of the Heat and Moisture Transport interface isfound (along with the Moist Air and Building Materials versions) under the Heat andMoisture Transport group in the Heat Transfer branch in the model wizard. It adds theHeat Transfer in Moist Porous Media interface, the Moisture Transport in PorousMedia interface, and the Heat and Moisture multiphysics node.
The Heat Transfer in Moist Porous Media interface is a new version of the Heat
Transfer interface, only available with the Moist Porous Media version of the Heat andMoisture Transport interface and having the new Moist Porous Medium domain featureas the default model.
The new Moist Porous Medium domain feature of the Heat Transfer interface is similar
to the new version of the Porous Medium node, but with Porous Matrix, Moist Air, andLiquid Water subnodes. The effective material properties defined in the Moist Porous
Medium node account for the solid, liquid water, and moist air properties. The Moist
Air subnode defines the material properties by taking into account the moisture
content, and computes the convective flux and diffusive enthalpy flux in moist air. The
Liquid Water subnode defines the liquid water saturation and velocity field, which may
be automatically set by the Heat and Moisture multiphysics coupling if available.
The new Porous Media Flow version of the Moisture Flow interface is found (along with
the Laminar Flow and Turbulent Flow versions) under the Moisture Flow group in theChemical Species Transport branch in the model wizard. It adds the Brinkman
Equations interface, the Moisture Transport in Porous Media interface, and theMoisture Flow multiphysics node.

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The new Porous Media Flow version of the Heat and Moisture Flow interface is found(along with the Laminar Flow and Turbulent Flow versions) under the Heat and Moisture
Flow group in the Heat Transfer branch in the model wizard. It adds the Brinkman
Equations interface, the Moisture Transport in Porous Media interface, the Heat
Transfer in Moist Porous Media interface, and the Moisture Flow multiphysics node.
The definition of the moisture variables has been updated in the Heat Transfer
interface to improve numerical accuracy in concentrated species conditions when the
air concentration is small. This update affects the vapor mass fraction, vapor
concentration, moisture content, and relative humidity variables.
Finally, the diffusive flux of thermal enthalpy is now accounted for when modelingcoupled heat and moisture transport in moist air with the Heat and Moisturemultiphysics coupling node.
THERMAL CONTACT, SYMMETRY, AND ADDITIONAL IMPROVEMENTS FOR
LAYERED MATERIAL FEATURESThe new Thermal Contact, Interface feature is available in the Heat Transfer in Shells
interfaces. It allows you to represent the surface asperities and the fluid gap at theinternal interfaces between the layers of a layered shell. It is available when the Shell
type is Layered shell in the Shells Properties section of the parent physics interface.
The new Symmetry feature is available in the Heat Transfer in Shells interfaces. It allows
you to set a no flux boundary condition for symmetry edges, adjacent to the layeredboundaries selected in the parent interface.
In the Thermoelectric Effect, Layered Shell coupling node, the conversion of thecoupling variables from the spatial frame to the material frame has been improved.
The handling of the heat fluxes and sources, added by the subfeatures available under
the Thin Layer, Thin Film, and Fracture features, has been improved on externalboundaries, when an Isothermal Domain Interface is also active.
AUTOMATIC DETECTION OF IDEAL GAS MATERIAL IN HEAT TRANSFER
IN FLUIDSThe Fluid feature, available within the Heat Transfer interfaces, has been updated totake advantage of the ideal gas assumption to improve computational efficiency. The
new From material option of the Fluid type list automatically detects whether thematerial applied on each domain selection is an ideal gas or not, and uses the relevant
properties for either case. This may speed up computation when computing pressure

94 |CHAPTER 1: RELEASE NOTES

work in compressible nonisothermal flows, for example. The Moist air option has been
removed from the Fluid type list as it is handled in the dedicated Moist air feature.
When the Heat Transfer interface is coupled to a Fluid Flow interface through theNonisothermal Flow coupling node, the density may be taken from the coupled Fluid
Flow interface or from the coupling node. In this case, the user interface of the Fluidfeature has been simplified to show only the relevant user inputs.
HEAT AND ENERGY BALANCE

New and updated variables are available for heat and energy balance control in
postprocessing. Among them:• Updated definition of the ht.mujtT variable, accounting for compressibility of theflow and taking advantage of the ideal gas assumption when applicable.
• Updated definition of the ht.WInt variable, using the new ht.Wtot,
ht.WBndTot_u, and ht.WBndTot_d variables and accounting for the work ofvolume forces and boundary stresses.
• New ht.Wstr and ht.WstrInt (replacing ht.WnsInt) variables, accounting for the
total stress power (including viscous dissipation and pressure work).
• New ht.nthflux, ht.nthflux_u, and ht.nthflux_d variables to account forenthalpy flux on boundaries.
• Updated definition of the ht.ntefluxInt variable on boundaries adjacent to an
Isothermal Domain feature, not relying on the gradient of temperature.
• Updated definition of the ht.ndflux_u and ht.ndflux_d variables in Infinite
Elements and axisymmetric domains.
• Update of the ht.Qoop variable to account for out-of-plane heat source in theenergy balance and residuals.
• New ht.Qltot, ht.Qlrtot, and ht.Qitot variables and use of these variables inthe expression of ht.QInt, to account for point and line heat sources in the energybalance.
• Update of the ht.q0 variable.
In the Heat Transfer in Shells interfaces, there is an improved definition of most for
the heat and energy balance variables.
MISCELLANEOUS• The Nonisothermal Flow multiphysics coupling now supports partial domain
selection among the coupled fluid flow and heat transfer interfaces. In particular, it
makes it possible to couple the Heat Transfer in Fluids interface to a Laminar Flow

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interface in one part of the domain, and to a Turbulent Flow interface in anotherpart, by adding two multiphysics coupling nodes, one for each part of the domain.
If the variables that are meant to be synchronized between the coupled interfaces(velocity, pressure, temperature) are not available on some part of the domain, theCommon Model Input value is used instead.
• In the Lumped Thermal System interface, all the two-pin components and terminal
nodes now have an Initial Values section that provides one or two user inputs for the
initial temperature at nodes. This allows the use of, for example, the output of
another study or a user-defined value for the temperature in the thermal circuit.
• In the Irreversible Transformation subfeature, the new Initial Values section provides
an input to specify a user-defined value for the Initial irreversible transformation
indicator.
• In the Thermal Damage subfeature, the new Initial Values section provides inputs tospecify user-defined values for the Initial damage tissue indicator and Initial instantnecrosis indicator.
• The scaling of the equations in the Electromagnetic Heating, Electrochemical Heating,and Thermoelectric Effect multiphysics coupling features has been improved when a
Scaling System node is added under the Definitions node.
• The computation of heat sources on boundaries adjacent to both a solid and aporous medium domain has been improved.
• In the Heat Flux feature, the definition of the heat transfer coefficient for Internal
forced convection in an Isothermal tube has been improved, with the evaluation of
the fluid material properties at the average between the surface and the external
temperatures.
The Inflow and Outflow features are now available as fallback features for the pairfeatures.

New Applications in Version 5.6
FREEZE DRYINGThis example simulates primary freeze drying of skim milk in a vial under vacuumchamber conditions. This process, also known as lyophilization, can be used topreserve high-value products in the pharmaceutical and food industries. It relies on
sublimation of the product. The tutorial computes the phase change front from a solid
frozen state to a gaseous state and the vapor flow in the pores of the dried product bysolving for heat transfer in both phases and applying the Stefan condition at the phase

96 |CHAPTER 1: RELEASE NOTESchange front. The Deformed Geometry interface is used to compute the coupled heatand mass transfer on a moving mesh tracking the ice surface.

Updated Applications in Version 5.6
The tutorials have been updated to take advantage of the latest geometry, mesh, andsolver features in order to have simplified step-by-step instructions for the model
construction. In addition to these updates, some tutorials have been updated
regarding physical modeling:• The Tin Melting Front tutorial has been updated with the use of the new Phase
Change Interface feature to capture the phase change front.
• The Evaporation in Porous Media with Large Evaporation Rates tutorial has
been updated with the use of the new Moisture Transport in Porous Media interface
to model the transport of vapor and liquid water through the porous medium.
• The Inline Induction Heater tutorial now uses boundary layer meshes on faces.
The Thermal Performances of Roller Shutters tutorial now uses a corrected
equivalent thermal conductivity for the slightly ventilated cavity.

Backward Compatibility with Version 5.5• The Heat and Moisture multiphysics coupling feature is no longer applicable todomains where the Fluid (Heat Transfer interface) feature is active. Models built inversion 5.5 and before, where the Heat and Moisture multiphysics feature and the
Fluid feature with the Moist air option have been used, are updated when opened inversion 5.6. The Fluid feature is then replaced by the Moist air feature so themultiphysics coupling is still active. In the unexpected case where the Heat andMoisture multiphysics feature and the Fluid feature with an option other than Moist
air were combined, the multiphysics coupling is no longer active in version 5.6,
which is likely to modify the model solution.
• In the Surface-to-Surface Radiation interface, the Opaque Surface andSemitransparent Surface features not supporting directional dependence of surface
properties are now obsolete. When opening a model created in version 5.5 or earlier
in the user interface, these features are not migrated. They should be manuallyreplaced by the new Opaque Surface and Semitransparent Surface features to accountfor directional dependence of surface properties. Support for features marked as
obsolete is not ensured in future versions; thus it is strongly recommended totransfer all these features to the new features.

HEAT TRANSFER MODULE|

97• In the Heat Transfer interfaces, the Porous Medium feature not supporting the new
Porous Material functionality is now obsolete. When opening a model created inversion 5.5 or earlier in the user interface, this feature is not migrated. It should be
manually replaced by the new Porous Medium feature (which comes with Porous
Matrix and Fluid subfeatures) to allow an updated definition of the material
properties of the porous medium. Support for features marked as obsolete is not
ensured in future versions; thus it is strongly recommended to transfer this feature
to the new feature.
• The Temperature feature is no longer applicable on boundaries adjacent to a domain
where the Isothermal Domain feature is active. When opening a model built inversion 5.5 and before, where the Temperature feature is applied in this way, thenode is present but the feature is not active, which is likely to modify the model
solution.
• The Open Boundary feature is no longer applicable on boundaries adjacent to a
nonfluid domain. When opening a model built in version 5.5 and before, where theOpen Boundary feature is applied in this way, the node is present but the feature is
not active, which is likely to modify the model solution.
• The Surface-to-surface radiation interface is no longer applicable on boundaries thatbelong to infinite element domains, perfectly matched layer domains or absorbing
domains since the view factor computation does not account for the corresponding
coordinate system change.

Backward Compatibility with Version 5.4• In the Inflow feature (Heat Transfer interface), the Upstream absolute pressure user
input is now inactive, unless the new Specify upstream absolute pressure check box
is selected. Scripts using the COMSOL API that used to fill this input field need to
add an instruction for selecting the Specify upstream absolute pressure check box
beforehand.
• The Open Boundary feature now comes with a new default formulation based on the
Danckwerts inflow condition to specify the incoming temperature. The former
default formulation is still available by choosing the Discontinuous Galerkinconstraints option in the Inflow Condition section. To keep the former default
formulation in scripts using the COMSOL API, you need to add the corresponding
instruction to set the Discontinuous Galerkin constraints option in the Inflow Condition
section.

98 |CHAPTER 1: RELEASE NOTES• When the Relative humidity option is used in the Moisture Content boundary
condition, the associated temperature now has to be defined. In version 5.4 andbefore, the moisture transport local temperature was used instead. In order toreproduce previous results, models created in version 5.4 or earlier will use themoisture transport interface temperature when opened in the GUI. The scripts
using the COMSOL API will use the default temperature 293.15 K instead and mayneed to be updated to reproduce existing results.
• In the Heat Flux, Interface and Heat Source, Interface features, when the Heat Rate
option is selected in the Heat Flux and Boundary Heat Source sections, respectively,
the surface definition has been corrected in order to take into account several
interfaces in the Interface Selection. For example, if two interfaces are selected, thesurface definition is now multiplied by two.
• The Deposited Beam Power, Interface and Surface-to-Ambient Radiation, Interface
features are now applicable on the interior interfaces. In the scripts using the
COMSOL API in which the All interfaces option was selected, the interior interfaces
were selected but no contribution was added on these interfaces. Changes in the
numerical results are expected now that the contribution is added also on theinterior interfaces.

Backward Compatibility with Version 5.3a
• The Heat Transfer in Thin Shells (htsh), Heat Transfer in Thin Films (htsh), andHeat Transfer in Fractures (htsh) interfaces that do not support the Layered Material
functionality are now obsolete. When opening a model created in version 5.3a or
earlier in the GUI, these interfaces are not migrated. They should be manuallyreplaced by the corresponding Heat Transfer in Shells (htlsh), Heat Transfer inFilms (htlsh), and Heat Transfer in Fractures (htlsh) interfaces that support theLayered Material functionality. The Thin Layer, Thin Film, and Fracture features are
replaced by the Solid, Fluid, and Porous Medium features in the new interfaces.
• The Thin Layer, Thin Film, and Fracture features (and their subfeatures) that do notsupport the Layered Material functionality are now obsolete. When opening a model
created in version 5.3a or earlier in the COMSOL Desktop, these features are notmigrated. They should be manually replaced by the corresponding features that
support the Layered Material functionality. Note that the pair features for thin
structures are no longer available for layered materials. The obsolete Thin Layer, Thin
Film, and Fracture features remain available through the COMSOL API so thatexisting scripts remain compatible. However, it is recommended to update theHEAT TRANSFER MODULE|

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scripts to use the new features as the obsolete features will be discontinued in futureversions.
• The Surface-to-surface radiation check box has been removed from the Physical Modelsection of the Heat Transfer interface. As of version 5.4, surface-to-surface radiation
models should use the Surface-to-Surface Radiation physics interface coupled witha Heat Transfer domain physics interface via the Heat Transfer with Surface-toSurface Radiation multiphysics coupling feature. The Heat Transfer interface does
not support the Diffuse Surface, Diffuse Mirror, Prescribed Radiosity, Opacity, andExternal Radiation Source features anymore. Models built prior to v5.3a using
surface-to-surface radiation features formerly available in the Heat Transfer
interfaces will mark these features as obsolete. Support for features marked as
obsolete is not ensured in future versions, thus it is strongly recommended totransfer all these features to a Surface-to-Surface Radiation physics interface and use
a Heat Transfer with Surface-to-Surface Radiation multiphysics coupling feature.
• The Radiation in participating media check box has been removed from the PhysicalModel section of the Heat Transfer interface. From version 5.4, radiation inparticipating media models should use the Radiation in Participating Media physics
interface coupled with a Heat Transfer physics interface via the Heat Transfer with
Radiation in Participating Media multiphysics coupling feature. The Heat Transfer
interface does not support the Radiation in Participating Media, Opaque Surface,
Incident Intensity, and Continuity on Interior Boundary features anymore. Models
built prior to v5.3a using radiation features formerly available in the Heat Transfer
interfaces will mark these features as obsolete. Support for features marked as
obsolete is not ensured in future versions, thus it is strongly recommended totransfer all these features to a Radiation in Participating Media physics interface anduse a Heat Transfer with Radiation in Participating Media multiphysics coupling
feature.
• The Ambient Settings section has been removed from the Heat Transfer interface.
When opening a model created in version 5.3a or earlier in the COMSOL Desktop,
in which some of the input fields of this section have been edited, an Ambient
Thermal Properties node is automatically created under Definitions>Shared Properties
with the same settings. If some ambient variables have been selected in features, thefeature inputs are updated as well.
• The Phase Change Material feature has been replaced by the Phase Change Material
subfeature. When opening a model created in version 5.3a or earlier in the
COMSOL Desktop, a Fluid node with the Phase Change Material subfeature is

100 |CHAPTER 1: RELEASE NOTESautomatically created in place of the obsolete feature. This node is labeled Phase
Change Material in the model.
• The Damaged Tissue section has been removed from the Biological Tissue feature.
When opening a model created in version 5.3a or earlier in the COMSOL Desktop,
in which the Include damage integral analysis check box of this section has been
selected, a Thermal Damage node is automatically added under Biological Tissue withthe same settings. Note that for the Temperature threshold option, it is no longer
possible to perform simultaneous hyperthermia and cryogenic analysis. The
Hyperthermia analysis option is therefore selected by default when opening themodel.
• The Rosseland approximation option, which was available in the Radiation
discretization method list of the Radiation in Participating Media feature, has been
removed. When opening a model created in version 5.3a or earlier in the COMSOLDesktop, in which this option has been selected, an Optically Thick Participating
Medium subnode is automatically created under the active domain node.
• The Medium Properties feature has been renamed Absorbing Medium in the Radiative
Beam in Absorbing Medium interface, with identical settings and modeling. Whenopening a model created in version 5.3a or earlier in the COMSOL Desktop, an
Absorbing Medium feature is automatically created in place of the obsolete feature.
This node is still labeled Medium Properties in the model.
• The Radiation in Participating Media feature has been renamed Participating Medium
in the Radiative Beam in Absorbing Medium interface. When opening a model
created in version 5.3a or earlier in the COMSOL Desktop, a Participating Mediumfeature is automatically created in place of the obsolete feature. This node is stilllabeled Radiation in Participating Media in the model.
• The Change Thickness and Change Cross Section features have been renamed Thickness
and Cross Section, respectively. When opening a model created in version 5.3a or
earlier in the COMSOL Desktop, these features are not migrated. They should be
manually replaced by the new features.

Backward Compatibility with Version 5.3• The Electromagnetic Heat Source and Boundary Electromagnetic Heat Source coupling
features are now obsolete. They have been merged into a single Electromagnetic
Heating coupling feature. When opening a model created in version 5.3 or earlier in
the COMSOL Desktop, the Electromagnetic Heat Source and Boundary
Electromagnetic Heat Source features are automatically migrated to Electromagnetic

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Heating features with selections (respectively a domain and a boundary selection)that match the selections of the migrated features. The obsolete Electromagnetic
Heat Source and Boundary Electromagnetic Heat Source features remain available

through the COMSOL API so that existing scripts remain compatible. However, it
is recommended to update the scripts to use the new Electromagnetic Heating featureas the obsolete feature will be discontinued in future versions. Note thattemperature coupling is enforced in the 5.3a version of the Electromagnetic Heating
coupling feature.
• The Thermoelectric Effect and Boundary Thermoelectric Effect coupling features havebeen merged into a new Thermoelectric Effect coupling feature. When opening amodel created in version 5.3 or earlier in the COMSOL Desktop, the Thermoelectric
Effect and Boundary Thermoelectric Effect features are automatically migrated to the
new Thermoelectric Effect feature with selections (respectively a domain and aboundary selection) that match the selections of the migrated features. The obsolete
Thermoelectric Effect and Boundary Thermoelectric Effect features remain available
through the COMSOL API so that existing scripts remain compatible. However, it
is recommended to update the scripts to use the new Thermoelectric Effect feature as
the obsolete feature will be discontinued in the future. Note that temperature
coupling is enforced in the 5.3a version of the Thermoelectric Effect coupling feature.
• The Inflow Heat Flux boundary condition is now obsolete. It can be replaced by the
new Inflow boundary condition and the Boundary Heat Source condition.
• The Enable conversions between material and spatial frame check box, displayed in
the Advanced Settings section of the Heat Transfer interfaces when the modelcomponent supports moving mesh, has been removed. This means that conversion
between material and spatial frames is always effective when these frames differ.
• The Energy absorption option has been renamed Arrhenius kinetics in theTransformation model list of the Irreversible Transformation and Biological Tissue
nodes.
• The Convective moisture flux option has been renamed Convective moisture flux,pressures difference in the Moisture Flux node.
• The rhoInt, CpInt, and gammaInt variables, defined by the Fluid domain feature,
have been removed.
• The q_evap variable, defined by the Moist Surface and Wet Surface boundary nodes,
has been replaced by the q_evaptot variable.
The General option for Thin film model has been removed from the Thin Film fallback
node.

102 |

CHAPTER 1: RELEASE NOTESM E M S M o dule
New Functionality in Version 5.6
FERROELECTROELASTICITY MULTIPHYSICS INTERFACEThe new Ferroelectroelasticity multiphysics interface is intended for analysis offerroelectric materials. These materials exhibit nonlinear piezoelectric properties. This
interface will add Solid Mechanics and Electrostatics interfaces, together with the new
Electrostriction multiphysics coupling. In Electrostatics, the new Charge Conservation,
Ferroelectric material model is used. In this material, it is possible to model, forexample, hysteresis using a Jiles–Atherton model.
ELECTROSTRICTION MULTIPHYSICS INTERFACE

With the new Electrostriction multiphysics interface, you can model electrostriction
phenomena; that is, a situation where a strain proportional to the square of thepolarization is induced by an electric field. This interface will add Solid Mechanics andElectrostatics interfaces, together with the new Electrostriction multiphysics coupling.
In Electrostatics, the standard Charge Conservation material model is used.
SPRINGS AND DAMPERS CONNECTING POINTSIn the Solid Mechanics interfaces, a new feature called Spring-Damper has been added.
With it, you can connect two points with a spring and/or a damper. The points can begeometrical points, but they can also be abstract through the use of, for example,
attachments or direct connections to rigid bodies. The spring can either be physical,
with a force acting along the line between the two points, or described by a full matrix,
connecting all translational and rotational degrees of freedom in the two points. The
feature also makes it possible to connect a spring between points in two different
physics interfaces.
PORT BOUNDARY CONDITION FOR ELASTIC WAVE PROPAGATIONThe new Port boundary condition, available with the Solid Mechanics interface, isdesigned to excite and absorb elastic waves that enter or leave solid waveguidestructures. A given Port condition supports one specific propagating mode.
Combining several port conditions on the same boundary allows a consistenttreatment of a mixture of propagating waves; for example, longitudinal, torsional, andtransverse modes. The combined setup with several Port conditions provides a superior
nonreflecting condition for waveguides to, for example, a perfectly matched layer

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(PML) configuration or the Low-Reflecting Boundary. The Port condition supports
S-parameter (scattering parameter) calculation, but it can also be used as a source tojust excite a system. The power of reflected and transmitted waves is available inpostprocessing. To compute and identify the propagating modes, the Boundary Mode
Analysis study is available in combination with the Port conditions.
GENERALIZED PLANE STRAIN WITHOUT BENDING

When using generalized plane strain for 2D Solid Mechanics, it is now possible tochoose that the out-of-plane strain is limited to be constant over the cross section. You
control this behavior through the new Enable out-of-plane bending check box in the 2D
Approximation section in the settings for the Solid Mechanics interface.
NEW OPTION FOR PRESCRIBING ROTATING FRAME SPEED

In the Rotating Frame node in the Solid Mechanics and Multibody Dynamics interfaces,
the new option Rigid body has been added. With this option, you enter a timedependent torque around the axis of rotation, and the rotational velocity is computed
by integration of the rigid body equation of motion.
IMPROVED DYNAMIC CONTACT

New algorithms have been introduced in order to improve the conservation of
momentum and energy during transient contact events. These can be activated by
selecting either the Penalty, dynamic or the Augmented Lagrangian, dynamic formulationin the Contact node.
MORE OPTIONS FOR PENALTY FACTORS IN CONTACT

When using the penalty method for contact analysis, there are three new options in theContact and Friction nodes for controlling the value of the penalty factor: Automatic,
soft, Manual tuning, and Nonlinear.
When using the augmented Lagrangian method with a preset penalty factor, there is
one new option: Bending. The purpose is to provide a softer penalty factor that canstabilize the iterations for bending dominated problems.
FULLY COUPLED SOLUTION METHOD FOR AUGMENTED LAGRANGIANMETHOD IN CONTACT

It is now possible to also use a fully coupled solver together with the augmented
Lagrangian contact algorithm. This makes it easier to set up solver sequences, and may
also improve stability and convergence for some problems. The new formulation,

104 |CHAPTER 1: RELEASE NOTESallowing a fully coupled solver, is selected in the Solution method list in the settings for
the Contact node.
USER-DEFINED FRICTION MODEL

In the Friction node under Contact, you can now also select User defined as the Friction
model. In this case, you directly enter an expression for the tangential force that causes
sliding in terms of any other variables.
NEW VISCOELASTICITY MODELSTwo new viscoelasticity models have been added: Maxwell and Generalized Kelvin–
Voigt.
The Maxwell material can be considered as a type of liquid, since its long-term
deformation under a constant stress is unbounded.
The Generalized Kelvin–Voigt model has a Prony series representation with several
time constants. Conceptually, it consists of a set of Kelvin elements (spring anddashpot elements in parallel) connected in series.
FRACTIONAL DERIVATIVE VISCOELASTICITY

For frequency-domain analysis, all the viscoelasticity models (Generalized Maxwell,
Generalized Kelvin–Voigt, Maxwell, Kelvin–Voigt, Standard linear solid, and Burgers)
have been augmented by a fractional derivative representation.
Using a fractional time derivative representation makes it easier to fit material data toexperiments for some materials.
NEW TEMPERATURE SHIFT FUNCTION IN VISCOELASTICITYThe Tool–Narayanaswamy–Moynihan shift function is commonly used to describe theglass transition temperature in glasses and polymers. It has been added to the set ofshift functions in the Viscoelasticity node.
PERFORMANCE IMPROVEMENTS FOR VISCOELASTICITY

For time-domain analysis using the Generalized Maxwell and Standard Linear Solidviscoelastic models, performance has been improved by up to one order of magnitude.
The viscoelastic stresses are no longer represented by ordinary shape functions, butwith state variables in the Gauss points.
ANALYSIS OF LARGE DEFORMATION PROBLEMS IN AN UPDATED FRAME

When analyzing problems with large deformations, it is now possible to do so in amanner where the material frame is updated between each parameter value. A

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deformed geometry approach is used, and the deformation implicit in thetransformation between the two frames is injected as a prestrain in the material modelin the updated geometry. To enable this functionality, you add an Elastic
Predeformation node.
STRAIN FIELD CONSISTENT INTERPOLATION OF INELASTIC STRAINCONTRIBUTIONS

Several physical interactions, for example, thermal expansion and hygroscopic swelling,cause inelastic strains that are incorporated in the material models. If such strain fields
vary too much over an element, spurious artifacts can be seen in the resulting stressfields. In version 5.6, this is taken care of by a reinterpolation so that the external strain
field has a polynomial order that matches the total strains computed from thedisplacements. In particular, this means that in a multiphysics analysis, thediscretization orders in the two participating interfaces can be chosen independently,
without considering consistency.
As an effect, the Thermal Stress, Solid and Joule Heating and Thermal Expansion
multiphysics interfaces no longer reduce the discretization order of the Heat Transfer
in Solids interface.
HARMONIC PERTURBATION FOR GRAVITYThe Gravity node in the structural mechanics interfaces now has the Harmonic
Perturbation option. This is useful when a support excitation is transformed into aframe acceleration.
SOLVER SETTINGS CONTROL FOR ELASTIC WAVES

In the settings for the Solid Mechanics interface, a new section Transient Solver Settings
has been added. The purpose is to generate appropriate solver settings when analyzing
wave propagation problems in the time domain.

New Models in Version 5.6
A MICROMACHINED COMB-DRIVE TUNING FORK RATE GYROSCOPE

This tutorial example of a comb-drive tuning fork gyroscope is kindly provided by Dr.
James Ransley at Veryst Engineering, LLC. The model demonstrates fully
parameterized geometry, extensive use of selection features, implementation ofanalytic formulas for the electromechanical forces and response estimation, andcomparison of numerical results with analytical estimations. In particular, extrusion
operators are used to compute the distances between electrodes for force calculation.

106 |CHAPTER 1: RELEASE NOTESMANUFACTURING VARIATION EFFECTS IN A MICROMACHINED COMBDRIVE TUNING FORK RATE GYROSCOPE

This tutorial example is kindly provided by Dr. James Ransley at Veryst Engineering,
LLC. This model continues from the base model “A Micromachined Comb-Drive
Tuning Fork Rate Gyroscope”, which is also provided by Dr. Ransley. The model
demonstrates how to accurately compute the effects of manufacturing variations of
MEMS devices without the need of very fine mesh. This highly efficient modelingapproach is based on the unique Deformed Geometry functionality of COMSOLMultiphysics, which implements the device shape change due to fabrication
imperfections using the same mesh, thus eliminating the error introduced if different
meshes are used for different geometries.
A PIEZOELECTRIC MICROPUMPThis tutorial model is kindly provided by Riccardo Vietri, James Ransley, and Andrew
Spann at Veryst Engineering, LLC. Piezoelectric micropumps are frequently used in
medical applications because of their ability to precisely control the metering of verysmall volumes of fluids or gases. This example shows how to simulate a simple,
nonresonant micropump, suitable for low-flow-rate applications. The model
demonstrates the combination of piezoelectric materials with a fluid-structureinteraction, and also illustrates the use of a simple velocity-dependent formula toaccount for the presence of valves on the inlet and outlet boundaries.
HYSTERESIS IN PIEZOELECTRIC CERAMICS

Many piezoelectric materials are ferroelectric. Ferroelectric materials exhibit nonlinear
polarization behavior such as hysteresis and saturation at large applied electric fields.
In addition, the polarization and mechanical deformations in such materials can bestrongly coupled due to the electrostriction effect. This model uses the
Ferroelectroelasticity interface to analyze a simple actuator made of PZT piezoelectric
ceramic material, which is subjected to an applied electric field and mechanical load.
MECHANICAL MULTIPORT SYSTEM: ELASTIC WAVE PROPAGATION IN A
SMALL ALUMINUM PLATE

In this tutorial, the vibrational behavior of a small aluminum plate with four waveguidestructures is analyzed. This is an example of a structural component located in a device
where elastic waves are propagating, like a smart speaker, an electric motor, or a MEMS
device. The plate can be thought of as a mechanical multiport system. The model uses
the Port boundary condition at the inlet/outlet of the waveguide structures. The port
conditions consistently capture and treat the different propagating elastic modes likelongitudinal, transverse, and torsional waves. The transmission and reflection of the

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various modes is characterized through the scattering matrix of the system, which iscomputed automatically. This allows the vibrational behavior of the component to be
characterized in great detail, for example, for subsequent use in a system simulation.

108 |CHAPTER 1: RELEASE NOTESM e ta l P r o c e s s i n g Mod u l e
New Functionality in Version 5.6
THE CARBURIZATION INTERFACEA new interface has been added to the Metal Processing Module. The interface can beused to study the heat treatment process of carburization. The carbon potential of thesurrounding atmosphere can be defined as a boost-diffuse cycle or as user defined. The
carbon exchange between a component and its surroundings can be modeled either byprescribing the carbon concentration directly or by applying a carbon flux boundary
condition.
IMPORT OF MATERIAL PROPERTIES

It is now possible to import material properties from JMatPro® for steel quenching
purposes. Material properties are imported for the metallurgical phases austenite,
ferrite, pearlite, bainite, and martensite. The imported properties are temperaturedependent and can also depend on plastic strain and plastic strain rate.
MISCELLANEOUS• The Metal Phase Transformation and Austenite decomposition interfaces can now
be used in 0D. This allows for easier setup of phase transformation model parameter
calibrations.
• A Transformation times functionality has been added to the Metallurgical Phase nodes
in 0D. This functionality is provided to more easily compute data for transformation
diagrams.
• It is now possible to define lower and upper temperature limits for the Leblond–Devaux and Johnson–Mehl–Avrami–Kolmogorov phase transformation models.
• A Transformation Condition subnode has been added under the Phase Transformation
node. The purpose of this is to be able to add additional conditions on a given phasetransformation, such as a condition on cooling rate.

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New Models in Version 5.6
CALIBRATION AGAINST TTT DATAThis model shows how to calibrate the parameters of a phase transformation model toexperimentally obtained time temperature transformation (TTT) data. The model
requires the Optimization Module.

110 |CHAPTER 1: RELEASE NOTESMicrofluidics Module
New Functionality in Version 5.6• The total (or stagnation) pressure can now be specified on inlet and outlet
boundaries for incompressible flow. Both local and averaged values of the totalpressure can be imposed. This new functionality can, for example, be used in pumpsimulations.
• The Fully developed flow option on inlets and outlets and the Mass flow option on
inlets have a new default setting, Apply condition on each disjoint selection separately.
This option sets up a separate equation for each disjoint boundary selection.
• The External Fluid Interface feature has been replaced by the Free Surface feature.
• The Two-Phase Flow, Level Set and Two-Phase Flow, Phase Field interfaces havebeen restructured. The Level Set and Phase Field interfaces now have two Initial
Values nodes by default, and the previously used Initial Interface nodes have been
made obsolete. Instead, the phase interfaces are automatically detected and theinitial distribution of the level set or phase field function is solved for in the Phase
Initialization study step.
• New options for averaging density and viscosity across phase interfaces have been
added in the Two-Phase Flow, Level Set and Phase Field interfaces. In addition to
the default volume average, smoothed Heaviside functions and harmonic volume
averages can be used for both density and viscosity averaging. For viscosity
averaging, mass average and harmonic mass average are also available.
• The Porous Media Transport Properties feature in the Transport of Diluted Species
in Porous Media interface has been replaced by a Porous Medium feature
containing the two subnodes Fluid and Porous Matrix. The Porous Matrix node
includes support for Porous Material, which is also new in version 5.6.
• An Open Boundary condition has been added in the Level Set interface.

Backward Compatibility with Version 5.5
In the Level Set and Phase Field interfaces, the Initial Interface feature is now obsolete.
It does not need to be replaced, since the phase interfaces are automatically detectedfrom the selection of the Initial Values features and the initial distribution of the levelset or phase field function is solved for in the Phase Initialization study step.

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Backward Compatibility with Version 5.3a
NO FLUX FORMULATION

The formulation of the No Flux feature has been changed in the Transport of Diluted
Species and Transport of Diluted Species in Porous Media interfaces in version 5.4 sothat the flux relative to the convective flux is set to zero. The new formulation is used
when opening a model from a previous session. In the previous formulation, the total
flux was set to zero.

112 |CHAPTER 1: RELEASE NOTESM i x e r M o dule
New Functionality in Version 5.6
SUPPORT FOR FROZEN ROTOR STUDY STEP, CONTINUITY PAIR FEATURE
AND INTERIOR WALL IN PHASE TRANSPORT, MIXTURE MODEL
INTERFACES

Rotating machinery simulations of dispersed n-phase flow modeled with the Phase
Transport, Mixture Model interfaces can now be set up manually by adding a Rotating
Domain under Moving Mesh in Definitions and using a Continuity pair feature (forsliding mesh simulations) between the rotating and stationary domains. In addition,
quasistationary frozen rotor simulations can also be performed due to added support
for this study type.

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Multibody Dynamics Module
New Functionality in Version 5.6
RIGID BODY CONTACT AND FRICTION

Rigid body contact and friction functionality has been added. The new Rigid Body
Contact node in the Multibody Dynamics interface can be used to model meshless
contact between standard-shaped rigid bodies. In this version, it allows SphericalSpherical and Spherical-Arbitrary types of contact between the two rigid bodies. In caseof Spherical-Spherical contact, the destination can also be a hollow sphere having insideconcave boundaries as the contact boundaries. The contact formulation can be chosen
as either Penalty or Penalty, dynamic. Frictional effects can be included by adding a
Friction subnode. The friction force is modeled using a continuous friction law, whichis smooth and numerically stable but at the same time restricts the use of friction totime-dependent studies.
CLEARANCE JOINT

Joints between components of real-life systems do not always have a perfect fit. For theease of assembly and movement between parts, a small gap, called a clearance, is often
provided between the joined parts. The presence of a clearance can sometimes
adversely affect the performance of the system by generation of impact forces,
vibration, and noise. In order to model this effect, the new Clearance Joint node isadded in the Multibody Dynamics interface. This joint essentially allows a clearance
distance between the source and destination components. The clearance is an input inthis node. This joint allows all rotational degrees of freedom and behaves as a ball joint
in 3D and a hinge joint in 2D. A penalty method is used to enforce that the two objects
are within the specified clearance.
AUTOMATIC JOINT CREATION FROM GEOMETRYThis functionality makes the model setup easier for large multibody systems. A new
button Create Joints has been added in the Automated Model Setup section of theMultibody Dynamics interface. This button creates joints automatically by finding theobjects that are in assembly state and forming Identity Pairs among them. By default,
Prismatic Joint is created for Planar Boundaries, Hinge Joint is created for Cylindrical
Boundaries, and Ball Joint is created for Spherical Boundaries. It is also possible to choose
any other appropriate joint for a particular type of boundary. In general, the joints are
created for all identity pairs in the component, but it is possible to create joints only

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for some identity pairs by disabling the others. The joints created by this operation will
also be assigned appropriate information about source, destination, center, and axis.
NEW LUMPED-STRUCTURE CONNECTION COUPLING

The new multiphysics coupling Lumped-Structure Connection has been added toconnect lumped systems modeled using the Lumped Mechanical System interface tofinite element systems modeled using the Multibody Dynamics or any other structural
mechanics interface. The connection in the Lumped Mechanical System interface canbe made either using the External Source node or Displacement Node, depending onwhether the finite element component is connected to the lumped model at both ends
or one end only.
IMPROVEMENTS IN LUMPED MECHANICAL SYSTEM MODELINGThe lumped mechanical system modeling functionality has been improved:• Lumped mechanical systems now support nested subsystems. This makes it possible
to model more advanced and complicated systems.
• Support for parametric subsystems has been added. More than one subsysteminstance can be added with different input parameters. This makes it possible tocreate more general subsystem models.
NONLINEAR SPRING FOR JOINTS

A new option Spring type has been added in the Spring and Damper subnode of all Joint
nodes in the Multibody Dynamics interface. The Spring type option has the option to
specify Force as function of extension in addition to the existing Spring constant. Thisnew option makes it possible to model nonlinear springs in a joint by writing the springforce as a function of extension. In joints having rotational degrees of freedom,
Moment as a function of rotation is the corresponding option.
PHYSICS SYMBOLS FOR JOINTSSupport for Physics Symbols has been added for all the Joint nodes in the Multibody
Dynamics interface. The physics symbol used is different for each joint type. It is placedat the center of the joint and connectors are drawn from the joint center to all sourceand destination boundaries.

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IMPROVEMENTS IN CHAIN DRIVE MODELINGThe chain drive modeling functionality has been improved in the following aspects:• The response is significantly faster for large models.
• The geometry part selection identification has been improved, making it morerobust.
CHANGES IN ENFORCING GEOMETRIC NONLINEARITY

There are several nodes in the Multibody Dynamics interface that have been enforcing
geometric nonlinearity in all types of study steps. Some such nodes are Joints, Camfollower, and Prescribed rotation in Rigid Connector, Rigid Domain, and Gears. There aresome situations where this may not be desired. From version 5.6, geometric
nonlinearity is enforced only in time-dependent and stationary study steps.
NEW OPTION FOR PRESCRIBING ROTATING FRAME SPEED

In the Rotating Frame node in the Solid Mechanics and Multibody Dynamics interfaces,
the new option Rigid body has been added. With this option, you enter a timedependent torque around the axis of rotation, and the rotational velocity is computed
by integration of the rigid body equation of motion.
RIGID CONNECTOR IMPROVEMENTS

The Rigid Connector features have a set of improvements:• When the center of rotation is defined by a point selection, the point no longer has
to be part of the physics interface itself.
• It is possible to couple rigid connectors from different physics interfaces, thus
defining a new type of virtual rigid object. This selection resides in the Advanced
section of the settings for the rigid connector.
IMPROVED DYNAMIC CONTACT

New algorithms have been introduced in order to improve the conservation of
momentum and energy during transient contact events. These can be activated by
selecting either the Penalty, dynamic or the Augmented Lagrangian, dynamic formulationin the Contact node.
MORE OPTIONS FOR PENALTY FACTORS IN CONTACT

When using the penalty method for contact analysis, there are three new options in theContact and Friction nodes for controlling the value of the penalty factor: Automatic,
Soft, Manual tuning, and Nonlinear. When using the augmented Lagrangian method

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with a preset penalty factor, there is one new option: Bending. The purpose is to providea softer penalty factor that can stabilize the iterations for bending-dominatedproblems.
USER-DEFINED FRICTION MODEL

In the Friction node under Contact, you can now also select User defined as the Friction
model. In this case, you directly enter an expression for the tangential force that causes
sliding in terms of any other variables.
FRICTION WITH A KNOWN SLIDING VELOCITY

In some important applications, the direction of the friction force is known, since two
objects are sliding on each other with a given relative velocity. In this case, it is notnecessary to solve for the friction forces. Such an approach can speed up the solution
significantly. The new Slip Velocity node, added under Contact, can be used whenmodeling such cases. The inputs for this node are similar to those of the Friction node.
WEAR MODELING

Methods for modeling mechanical wear have been added. This is controlled from the
new Wear node, a subnode under Contact available in the Solid Mechanics andMultibody Dynamics interfaces.
There are two algorithms for wear modeling. In the more general, allowing arbitrarygeometry changes due to the wear, a deformed geometry approach is used. There isalso a simplified approach in which the wear is incorporated into the offset in thecontact gap.
COMPUTING ROTATION FROM DISPLACEMENTS

In physics interfaces that have displacements as degrees of freedom, it is sometimes
necessary to study the rotation of a region. To do that, you can add the new Average
Rotation node, which uses the displacements of a set of points to determine a rotation.
If more than three points are given, a least squares scheme is applied to make the best
approximation of a rigid body rotation for the entire set of points. In addition, angularvelocities and accelerations can be computed.
HARMONIC PERTURBATION FOR GRAVITYThe Gravity node in the structural mechanics interfaces now has the Harmonic
Perturbation option. This is useful when a support excitation is transformed into aframe acceleration.

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ITEMS MOVED IN CONTEXT MENUS

The context menu items Initial Values and Initially Rigid have been moved into the Moresubmenu in order to reduce the size of the menu.

New Models in Version 5.6
DYNAMICS OF A CYLINDRICAL ROLLER BEARINGThis model simulates the dynamics of a cylindrical roller bearing. Here, multiple
cylindrical rollers are inserted between the outer and inner race, and held in place withthe help of the cage. The inner race is connected to a rotating shaft and the outer race
to a fixed foundation. All components of the bearing are assumed rigid. Frictional
contact is modeled between rollers and races using rigid body contact with friction.
The connection between the rollers and the cage is simplified using hinge joints. An
external load is applied on the inner race and a transient study is performed to analyze
the lateral dynamics of the inner race, dynamics of rollers and cages, contact andfriction forces, and energy dissipation due to friction.
SLIDER CRANK MECHANISM WITH JOINT CLEARANCE

Joints between two components of a mechanical system are not always perfectly fitting.
For ease of assembly and to allow relative movement between the components, a small
gap called a clearance is provided that can sometimes adversely affect the performanceof the system by generating impact forces, thus giving rise to noise and vibrations. Thismodel compares the performance of a slider crank mechanism with and without a joint
clearance. All components of the mechanism are assumed to be rigid. A Hinge Joint isused when there is no clearance, whereas a Clearance Joint is used to include clearance.
A transient analysis is performed to analyze the effect of joint clearance on slider
velocity, slider acceleration, and crank moment. In addition to this, the dynamics of thejournal within the bearing and the reaction force in the clearance joint are also
analyzed.
MODELING VIBRATION AND NOISE IN A GEARBOX: BEARING VERSIONThis example is an extension of the model Modeling Vibration and Noise in a
Gearbox. In this version of the model, a detailed representation of the roller bearings
is used to connect the shafts with the housing, rather than a hinge joint. Due to thefinite stiffness of the bearings, the vibration response of the system can be significantly
different from that obtained using the rigid bearing assumption. In this model, a 5–
speed synchromesh gearbox of a manual transmission vehicle is studied. First, thegearbox vibration is computed using a time-dependent analysis for the specified engine

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speed and external load. The normal acceleration of the gearbox housing is converted
to the frequency domain and used as a source of noise. Finally, an acoustics analysis isperformed to obtain the sound pressure levels in the near, far, and exterior fields.

Updated Models and Apps in Version 5.6
UPDATED MODELS

The following models have been updated significantly:• Three-Cylinder Reciprocating Engine: Uses the new automatic joint creation
functionality.
• Reciprocating Engine with Hydrodynamic Bearings: Uses the new automatic joint
creation functionality.
• Lumped Model of a Vehicle Suspension System: Uses the new Lumped-Structure
Connection node.
UPDATED APPS

The following apps have been updated significantly:• Centrifugal Governor Simulator: The layout of this app has been changed
significantly. It also now uses many local forms instead of global forms.
• Truck-Mounted Crane Analyzer: The layout of this app has been changed
significantly. It also now uses the new dark theme available in version 5.6.

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Nonlinear Structural Materials
ModuleNew Functionality in Version 5.6
PLASTICITY IMPROVEMENTS

A new subnode, called Set Variables, has been added under Plasticity and Porous
Plasticity nodes in the Solid Mechanics, Shell, Layered Shell, Membrane, and Truss

interfaces. These new nodes make it possible to reset plastic variables based uponboolean conditions for both small-strain and large-strain plasticity options.
POROUS PLASTICITY IMPROVEMENTS

The Capped Drucker–Prager model has been added to the Porous Plasticity feature
available for the Linear Elastic Material and Nonlinear Elastic Material models.
The Large Strain Plasticity option has been added to all the material models under the
Porous Plasticity node. The formulation uses a multiplicative decomposition of
deformation gradients, giving a good approximation also at high compressive strains.
NONLINEAR ELASTIC MATERIAL IMPROVEMENTS

A new material model called Shear data has been added. It is similar to the Uniaxial data
model, but intended for situations where shear stress vs. shear angle measurements areavailable.
Hardening data from the Material Library can now be used in the Uniaxial data material
model.
VISCOELASTICITY IMPROVEMENTS

Two more built-in viscoelastic models have been added to the Nonlinear Elastic
Material: the Maxwell model and the Generalized Kelvin model. For frequency-domain
analysis, it is possible to add fractional derivatives for all the built-in viscoelastic models.
As with the other viscoelastic models, it is accessed by adding a Viscoelasticity subnode
under the Nonlinear Elastic Material node.
When using a Viscoelasticity subnode under the Hyperelastic Material node, a new leaner
implementation for the Generalized Maxwell and Standard Linear Solid models forlarge-strain viscoelasticity is available, giving significant speedup.

120 |CHAPTER 1: RELEASE NOTESNEW HYPERELASTIC MATERIAL MODELS

Three new hyperelastic material models have been added: The Extended Tube model
for modeling rubber-like materials and the Delfino and anisotropic Fung material
models to simulate large deformations in biological tissue.
All the Hyperelastic Material models available in the Solid Mechanics interface are now
available in the Layered Hyperelastic Material node in the Shell interface. If theComposite Materials Module is available, the material models can also be used in
multilayered shells, and the individual layers can have different material models.
NONLINEAR MATERIAL MODELS IN THE LAYERED SHELL INTERFACEThe Linear Elastic Material in the Layered Shell interface now includes the possibility tomodel Large Strain Plasticity. The same set of yield functions and isotropic hardening
models as in the Solid Mechanics interface are available. The formulation assumes large
plastic strains, which gives a good approximation above 10% strain.
It is now possible to add Plasticity to the Hyperelastic Material in the Layered Shellinterface. The new subnode uses the Large Strain Plasticity formulation. The same setof yield functions and isotropic hardening models as in Hyperelastic Material models for
the Solid Mechanics interface are available.
The Layered Shell interface requires the Composite Materials Module.
DAMAGE IMPROVEMENTS

A new viscous regularization method for time-dependent analysis has been added to
the Damage feature.
New options, Polynomial strain softening and Multilinear strain softening, are available
for the damage evolution laws for Scalar damage and Mazars damage for concretemodels.
A new Phase field damage model has been added as an option to the Damage feature.
This new model is available with the Linear Elastic Material model in the Solid
Mechanics interface.
The Damage feature has been added to the Layered Linear Elastic material in the Shellinterface, and to the Linear Elastic Material model in the Layered Shell interface. The
Layered Shell interface requires the Composite Materials Module.
IMPROVEMENTS TO SHAPE MEMORY ALLOY

The user inputs for the Shape Memory Alloy material models are now available asmaterial properties.

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For the Lagoudas model, it is now possible to enter the material data in terms oftransition temperatures or transition stresses.
The Souza–Auricchio model is modified to account for the reference temperature
instead of the martensite finish temperature. The radius of the elastic domain is enteredinstead of the initial yield stress.
The Lagoudas and Souza–Auricchio models are now available in the Truss interface. The
Shape Memory Alloy node in the Truss interface also has the following subnodes:• Thermal Expansion• External Stress• Initial Stress and Strain• Phase Transformation
NEW DEFAULT PLOTS

New default contour plots, showing the inelastic strains, have been added for the
Plasticity, Viscoplasticity, Creep, Viscoelasticity, and Shape Memory Alloy features. Similarplots that were overlaid on the default stress plots have been removed.

New Models in Version 5.6
IMPACT ANALYSIS OF A GOLF BALL

In this example, the mechanical impact of a golf club hitting a golf ball is studied. The
contact between the two parts is modeled using a viscous penalty formulation tostabilize the dynamic event. The material of the ball is defined using a hyperelastic
material model so that the large deformations can be described. The core material is
viscoelastic and dissipates the elastic energy imposed by the impact. Results of thesimulation are compared to typical golf metrics such as ball speed and spin rate.
BRITTLE FRACTURE OF A HOLED PLATE

In this example, the brittle fracture of a holed plate with a notch is modeled using aphase field damage model. The geometry of the plate is set up so that a mixed-mode
fracture is induced. The dimensions and material properties of the plate are taken fromexperimental data. The example shows how to set up an efficient and stable solver
configuration for this kind of problem.

122 |CHAPTER 1: RELEASE NOTESINFLATION OF A SPHERICAL RUBBER BALLOON — SHELL AND
MEMBRANE VERSIONThis version of the balloon inflation example demonstrates how the Shell andMembrane interfaces can be used to model thin structures made of hyperelastic
materials.
PLASTIC STRAIN MAPPINGThis example shows the analysis of a perforated plate loaded into the plastic regime.
The purpose of the analysis is to demonstrate how plastic strains can be mapped
between dissimilar meshes.
POWDER COMPACTION OF A ROTATIONAL FLANGED COMPONENTThe powder compaction process is common in the manufacturing industry, thanks to
its potential to produce components of complex shape and high strength. In thisexample, the compaction of iron powder to form an axisymmetric rotational flanged
component is analyzed using the Capped Drucker–Prager plastic model. The friction
between the metal powder and die is taken into account.

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Optimization Module
New Functionality in Version 5.6
IPOPT OPTIMIZATION SOLVER

The IPOPT optimization solver has properties similar to SNOPT. The main authors
are Andreas Waechter and Carl Laird from IBM, but the code is still developed as an
open-source project with many contributors.
SAVE INTERMEDIATE SOLUTIONS FOR GRADIENT-BASED OPTIMIZATION

It is now possible to save the last N or every Nth solution for gradient-based
optimization. This simplifies troubleshooting and makes it possible to create
animations of the optimization history for presentation purposes.
SCALE OBJECTIVE FUNCTION WITH INITIAL VALUE

Most optimization solvers work best with scaled objectives, if there are active
constraints. Now the initial value for the objective function can be used as the scaled
objective function. This simplifies the setup of many constrained optimization
problems.
PARAMETER OPTIMIZATION

It is now possible to choose Copy Selected Rows to New Parameter Case for parameter
optimization. This is available by right-clicking a row in a table produced by one of thederivative-free optimization solvers.
SHAPE OPTIMIZATIONThe Symmetry/Roller feature now supports specifying a normal vector associated withan edge. This makes it simpler to set up some shape optimization problems for shells.
The behavior of the feature has improved in the context of axisymmetry.
TOPOLOGY OPTIMIZATIONThe Topology Link material is a new feature that combines a structural material with a
Density Model feature. It simplifies the workflow for structural topology optimization
because you no longer have to enter special expressions for the Young’s modulus or
the density.
The MMA optimizer has gained support for move limits, and it is no longer mandatory
to use the globally convergent MMA solver.

124 |CHAPTER 1: RELEASE NOTESA Prescribed Boundary Density feature has been introduced. It can be used to impose
constraints on density models that enable regularization with a Helmholtz filter.
Finally, the Parametric Sweep now has an option for reusing the solution from theprevious step. This simplifies the setup of parameter continuation where a sequence of
optimization problems are solved; the solution of one problem being used as the initialcondition for the next optimization problem.
You can use the graphics context menu for adding shape optimization and topology
optimization features.

New and Updated Models and Apps in Version 5.6
In general, the models and apps in the Application Library have been updated to use
shape- and topology optimization study steps, the IPOPT solver, the Topology Link,
and Model Wizard support for structural topology optimization.
• A new Optimization of a Photonic Crystal for Signal Filtering model(photonic_crystal_filter_optimization) changes the position of the pillars in thephotonic crystal in order to maximize the ratio of the transmission at the desired
frequency to the transmission at the undesired frequency. This model requires the
Wave Optics Module in addition to the Optimization Module.
• The Optimization of a Flywheel Profile model (flywheel_profile) has been
completely revised and updated and is now a 2D axisymmetric model.
• The General Parameter Estimation app (general_parameter_estimation) as well as
the Optimization Tutorials app in the Application Gallery have been updated tosupport the IPOPT solver.
• The Shape Optimization of a Shell model (shell_shape_optimization) has been
updated to use the new edge selection for the Symmetry/Roller shape optimization
feature.
• The Bracket — Topology Optimization model(bracket_topology_optimization_stl) takes advantage of the fact that parametricsweeps now support reusing the solution from the previous step, so the model nolonger has to use the withsol operator.
• Three new optimization models are available via the Application Gallery: Shape andTopology Optimization of Compliant Pliers, Shape and Topology Optimization of
an Extruded Beam, and Optimization of a Truss Tower.

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Backward Compatibility with Version 5.4
The computed solution in models using the Nelder-Mead, Coordinate search, orMonte-Carlo method should not change with Enforce design constraints strictly
enabled, compared to the solution obtained in the previous version. The number of
optimization iterations should either decrease or remain unchanged depending on thenumber of infeasible iterations. The computed solution in models using COBYLA candiffer with the Enforce design constraints strictly enabled.

126 |CHAPTER 1: RELEASE NOTESP a r t i c le T r a c in g Mod u l e
New Functionality in Version 5.6
PARTICLE PROPERTIES FROM MATERIAL

In the Particle Tracing for Fluid Flow interface, the particle material properties can
now be taken from a Material node instead of being specified directly. This change
allows the Material Libraries to be used more effectively in particle tracing models. It
also gets rid of the redundancy of having to specify the same property several times if
it is used by several different forces.
By default, every Particle Tracing for Fluid Flow model requires the particle density to
be specified. Depending on what additional forces and other features are added to themodel, other material properties might also be required. For example, theDielectrophoretic Force requires the particle relative permittivity and electricalconductivity. These will automatically be taken from the same material as the particle
density. You still have the option to change any material input back to User defined.
When using the new Droplet Evaporation node (see below) to treat the model particles
as evaporating droplets, you can also take the properties of the vapor phase fromanother Material node.

Backwards Compatibility
When opening any Particle Tracing for Fluid Flow model built in a version prior to
5.6, all particle material properties will be User defined.
NEW FORMULATION FOR TRACING SMALL PARTICLES IN FLUIDS

A new formulation is available for the Particle Tracing for Fluid Flow interface. Called
the Newtonian, ignore inertial terms formulation, it solves first-order equations for theparticle position while assuming that the drag force counterbalances all other forces on
the particles. In essence, this ignores the particle acceleration when particles are first
inserted into the fluid.
Ordinarily, the time step size you need in order to resolve particle acceleration in a fluid
scales with the square of the particle diameter. As a result, a full inertial treatment ofvery small particles (usually submicron size) requires extremely small time steps, andthe study can take a very long time to finish. The new Newtonian, ignore inertial terms
formulation allows much larger time steps to be taken without incurring any additional
numerical instability.

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DROPLET EVAPORATION

A built-in feature is now available to model evaporation of liquid droplets. The
evaporation rate is automatically computed based on the saturation vapor pressure at
the droplet surface and the diffusion coefficient of the droplet vapor in thesurrounding gas. The Droplet Evaporation node supports a simplified Maxwell diffusion
model, a more detailed Stefan–Fuchs model, and an option to specify the evaporation
constant directly.
NUMBER DENSITY CALCULATIONThe new Number Density Calculation feature can be used to compute the number
density of particles within the simulation domain. The density is averaged over eachdomain mesh element.
IMPROVED CONVECTIVE HEATING AND COOLING

When solving for particle temperature, there are now two different ways to apply
convective heating or cooling to the particles. In the settings for the Convective Heat
Losses node, you can now either specify the heat transfer coefficient h directly, or you
can specify the particle Nusselt number Nu and the thermal conductivity of the fluidk. The heat transfer coefficient will then be computed automatically.
RANDOM SAMPLING OF MASS, TEMPERATURE, AND OTHER VARIABLES

When you specify the initial values of an Auxiliary Dependent Variable for released
particles, you can now sample the initial values deterministically or randomly. In
previous versions, the sampling was always deterministic. You can sample from builtin normal, lognormal, or uniform distributions.
For the Particle Tracing for Fluid Flow interface, you can also sample the initial particle
mass or diameter from these distributions, deterministically or randomly. Whensampling the diameter, there is a built-in option to enter the Sauter mean diameter, acommon way to describe the size distribution of aerosol particles. The Sauter mean
diameter, along with other new variables for describing the particle size distribution,
are also available in postprocessing.
EASIER SAMPLING FROM UNIFORM DISTRIBUTIONSWhen a particle tracing model includes an Auxiliary Dependent Variable, or in theParticle Tracing for Fluid Flow interface when solving for particle mass or diameter,
you have the option of sampling the initial values of these extra variables from a Uniform
distribution. In previous versions, you had to specify the mean and standard deviation,
but now you can simply specify the minimum and maximum values.

128 |CHAPTER 1: RELEASE NOTESBackwards Compatibility
When an older model is loaded into version 5.6, if the initial value of an Auxiliary
Dependent Variable, particle mass, or particle diameter was sampled from a Uniform

distribution, the minimum and maximum are automatically defined to give the same
result as in the older model:
New minimum = (Old mean) - (Old standard deviation)*sqrt(3)New maximum = (Old mean) + (Old standard deviation)*sqrt(3)IMPROVEMENTS TO SPACE CHARGE LIMITED EMISSIONThe Space Charge Limited Emission Multiphysics coupling node, used with the Charged
Particle Tracing interface, has seen significant stability improvements and performance
upgrades in version 5.6.
Previous iterations of this feature computed the electric potential in a thin buffer
region between the particle emission surface and the cathode by attaching a 1D extra
dimension to the selected boundaries, essentially solving Poisson’s equation in theouter product space of this extra dimension and the selected boundaries. In version
5.6, this feature no longer defines an extra dimension, instead just applying a mixed
boundary condition on the electric potential at the emission surface that is consistent
with Child’s law (that is, the four-thirds power law).
This change reduces the overall number of degrees of freedom in models using theSpace Charge Limited Emission node. It also makes postprocessing easier because there

is no need to evaluate variables in an extra dimension. In addition, some bugs related
to the operation of this feature in 2D axisymmetric geometries were fixed.
VELOCITY OFFSET FOR THERMAL RE-EMISSION

The Thermal Re-Emission feature, which lets molecules be adsorbed onto a surface andthen released back into the simulation domain with a thermal velocity distribution,
now allows you to set a wall velocity. When tracing particles in a rotating frame ofreference (using the Rotating Frame node), there is also a built-in option to offset thewall velocity by the frame velocity, effectively making the wall stationary with respect
to the inertial (or laboratory) frame.
IONIZATION NODE IMPROVEMENTS

The Ionization node, which can be added to the Collision parent node in the Charged
Particle Tracing interface, has been improved. You can now separately control whether
the primary electron, secondary electron, and ionized species are released following
each ionization reaction.

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New and Updated Applications in Version 5.6
PIERCE ELECTRON GUN (NEW MODEL)

An electron gun must be able to draw a sufficient current and accelerate the electrons
to the desired speed. The first part of an electron gun geometry presents unique design
challenges because the emitted electron speeds are usually lowest there, and therefore
the space charge density is quite high. The Pierce electron gun design uses electrodes
with a particular shape to counteract the Coulomb repulsion between electrons in thebeam. As a result, the electrons in the beam propagate in straight lines. The emitted
electrons at the cathode are assumed to be space charge limited; the initial thermal
distribution of electron velocities is neglected.
TURBOMOLECULAR PUMP (UPDATED MODEL)The updated turbomolecular pump has a simplified geometry and an updated selectionof boundary conditions, including a more realistic treatment of the tip wall that
subtracts the rotating frame velocity from the velocity of the reflected particles. The
resulting compression ratios agree much better with published literature, compared toprevious versions of the model.

Backward Compatibility with Version 5.5
TEMPERATURES MOVED TO MODEL INPUT SECTION

In the Convective Heat Losses and Radiative Heat Losses nodes (available for the Particle
Tracing for Fluid Flow interface when the Compute particle temperature check box isselected), the input for the ambient temperature has been moved to the Model Input
section.

Backward Compatibility with Version 5.4
REMOVED THE PARTICLE TRAJECTORIES STUDY STEP

The Particle Trajectories study step is obsolete. All instances of this study step have been
replaced with Time Dependent study steps with the same settings.

130 |CHAPTER 1: RELEASE NOTESBackward Compatibility with Version 5.3 and Earlier
NOMENCLATURE CHANGES FOR MULTIPLE PARTICLE SPECIESThe Override Properties feature has been renamed to Particle Properties to emphasizethat it can be used to release multiple species of particles in the same model. The list
Inherit Properties in the settings for most particle release features, such as Inlet andRelease from Grid, has been renamed to Released particle properties.
TURBULENT DISPERSION CHANGESThe turbulent dispersion models used by the Drag Force in the Particle Tracing for
Fluid Flow interface have been modified and a deprecated turbulent dispersion model
has been removed.
The option Discrete random walk, variable time step has been removed from the
Turbulent dispersion model list. When an old model using this obsolete option is loadedin version 5.3a, the Discrete random walk option is now selected. However, Discreterandom walk actually behaves more like the old Discrete random walk, variable time stepmodel because it only samples the turbulent velocity perturbation at discrete timeintervals based on the eddy lifetime or eddy crossing time in the flow.
CHANGES TO RELEASE FROM EDGE AND POINT

In the Particle Tracing for Fluid Flow interface, the Release from Edge and Release from
Point features now allow the initial particle velocity to be selected from a list containing

previously computed velocity fields, similar to the behavior of the Release and Inletfeatures. This makes the Release from Edge and Release from Point features easier tocouple with another physics interface that models the fluid flow.
CHANGES TO PERIODIC ELECTRIC AND MAGNETIC FORCES

In models built in version 5.3 or earlier, if an Electric Force or Magnetic Force waspresent and the Multiply force by phase angle check box was selected, then in version
5.3a, Time harmonic will be selected from the new Time dependence of field list, which
replaces this check box.

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Pipe Flow Module
New Functionality in Version 5.6
FLUID-PIPE INTERACTION, FIXED GEOMETRY MULTIPHYSICSINTERFACE

The new Fluid-Pipe Interaction, Fixed Geometry interface connects the Pipe Flow andPipe Mechanics interfaces in order to transfer fluid loads to the structural analysis. The
new Fluid-Pipe Interaction multiphysics coupling is used. Internal pressure, drag forces,
loads on bends, and loads on junctions can be taken into account.
LICENSE UPDATE FOR PIPE ACOUSTICS

The Pipe Acoustics, Frequency Domain and Pipe Acoustics, Transient interfaces are now
available with either the Pipe Flow Module or the Acoustics Module.

Updated Model in Version 5.6
COUPLED ANALYSIS OF FLOW AND STRESS IN A PIPE

The model has been updated to make use of the new Fluid-Pipe Interaction, Fixed
Geometry interface.

Backward Compatibility with Version 5.3
The old Pipe Connection nodes, which could be added directly to the Pipe Flowinterface and Laminar Flow Interface, respectively, are now obsolete. The samefunctionality is available in a more convenient manner using the Pipe Connection
multiphysics coupling.

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Plasma Module
New Functionality in Version 5.6
Several interfaces in the Plasma Module were updated to reflect internal advances in
the COMSOL Multiphysics software. The affected interfaces are Plasma; Drift
Diffusion; Heavy Species Transport; Inductively Coupled Plasma; Microwave Plasma;and Boltzmann Equation, Two-Term Approximation. In general, the user interface,
functionality, and operation of the new interfaces are the same as in older versions.
However, there are fundamental internal changes that impede the possibility to havefull backward compatibility. Therefore, when opening a model created with aninterface before version 5.6, the model will still use the old interface. A warning sign
will appear in the interface indicating that the interface is obsolete. It is encouraged torecreate the model using version 5.6.
The finite volume formulation was completely reformulated and is now much morestable. This is a major advancement and makes it possible to have better performancein drift-dominated problems.

Backward Compatibility with Version 5.5 and Earlier
There are new versions of the following interfaces: Plasma; Drift Diffusion; Heavy
Species Transport; Inductively Coupled Plasma; Microwave Plasma; and Boltzmann
Equation, Two-Term Approximation. When opening models created with version 5.5
and earlier, a warning sign appears saying “This physics interface is obsolete and will
be removed in a future version. A new version of the physics interface is available fromthe Add Physics window”. These models can still be changed and will run as before,
but it is encouraged to recreate the models using version 5.6.

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Porous Media Flow Module
New Functionality in Version 5.6
LAYERED DARCY’S LAW INTERFACEThe Layered Darcy’s Law interface is used to simulate fluid flow through interstices inlayered porous media, such as paperboard, composites, or plywood. It can be used tomodel low-velocity flows and porous media where the permeability and porosity arevery small, and for which the pressure gradient is the major driving force.
POROELASTICITY, LAYERED SHELL MULTIPHYSICS INTERFACEThe new Poroelasticity, Layered Shell multiphysics interface allows the modeling ofmultilayer domains such as paperboard and composites having different material
properties per layer. The interface adds the Layered Shell and the Layered Darcy’s Law
interfaces, together with the new Layered Poroelasticity multiphysics node.
The Layered Shell interface requires the Composite Materials Module.
REVAMPED POROUS MEDIA FEATURES FOR TRANSPORT OF DILUTED
SPECIESThe Transport of Diluted Species in Porous Media interface, used to study the flow andchemical composition of fluids moving through the interstices of a porous medium, isrevamped to use the new Porous Material node.
Two new domain features, the Porous Medium and the Unsaturated Porous Medium
nodes, are available in the Transport of Diluted Species in Porous Media and Transport of
Diluted Species interfaces and include support for using the new Porous Material node
for assigning material properties to the multiple phases in a porous medium. The newnodes have subnodes to define the properties for the Liquid, Gas, and Porous Matrix.
The subnodes follow the same structure as the subnodes available in the Porous
Material.
The Dispersion and Volatilization in partially saturated porous media check boxes havebeen removed from the Transport Mechanisms settings. This functionality is now
available in the subnodes of the new Porous Medium and Unsaturated Porous Medium
nodes.

134 |CHAPTER 1: RELEASE NOTESThe new nodes replace the previously available Porous Media Transport Properties andPartially Saturated Porous Media nodes. These nodes are kept when opening a model
created in a previous version.
REVAMPED POROUS MEDIA FEATURES FOR HEAT TRANSFER

The Porous Medium feature is now always available without selecting the Heat transfer
in porous media check box, which has been removed.

The Porous Medium node has been revamped. The solid and fluid phases are now
handled in dedicated subnodes, namely the Porous Matrix and Fluid nodes. The
computation of the effective material properties is handled in the Porous Medium node,
whereas the solid and fluid properties are defined in the Porous Matrix and Fluid
subnodes. It is also possible to account for an additional immobile fluid phase byadding the Immobile Fluids subnode under the Porous Medium node.
In the new Porous Medium node, the settings are homogenized with those of theporous media features in the fluid flow and chemical species transport interfaces. In
particular, the Porosity is specified instead of the Volume fraction of the solid phase. In
addition, it is possible to set either the Dry bulk properties or the Solid phase properties,
depending on the availability of these material properties.
The new design allows to take advantage of the new Porous Material functionality under
the Materials node, in which the porosity and volume fractions may be set, and wherematerial properties are set in subnodes dedicated to each phase: Solid, Fluid, andImmobile Fluid.
MOISTURE TRANSPORT IN POROUS MEDIA

A set of new features are available for modeling coupled heat and moisture transportin porous media, saturated or partially saturated with moist air and liquid water.
The new Moisture Transport in Porous Media interface is found along with the MoistureTransport in Air and Moisture Transport in Building Materials interfaces under the
Moisture Transport group in the Chemical Species Transport branch in the Model
Wizard. The new Moisture Transport in Porous Media interface can handle moisturetransport in porous media by convection and diffusion of vapor, and by convection andcapillary flow of liquid water. The new Hygroscopic Porous Medium node extends thecapabilities of the Building Material node, by including convection in both gas andliquid phases due to total pressure variations, and by modeling the liquid capillary flux
with either Darcy’s law or a diffusion model. This new formulation is more generalthan the one implemented in the Building Material node, and it is intended for

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applications where the porous medium stays in the hygroscopic region regarding theamount of moisture.
The new Porous Media Flow multiphysics interface is available along with the Laminar
Flow interface under the Moisture Flow group in the Chemical Species Transport branchin the Model Wizard. It adds the Brinkman Equations interface, the new MoistureTransport in Porous Media interface, and the Moisture Flow multiphysics node.
HEAT AND MOISTURE TRANSPORT IN POROUS MEDIAThe Heat Transfer in Moist Porous Media interface is a new version of the Heat Transfer
interface, available with the Moist Porous Media version of the Heat and MoistureTransport interface, which adds the new Moist Porous Medium node as default. The new
Moist Porous Medium node is similar to the new Porous Medium node, but it includes
the Porous Matrix, Moist Air, and Liquid Water subnodes as default. The effective
material properties defined in the Moist Porous Medium node account for the solid,
liquid water, and moist air properties. The Moist Air subnode defines the material
properties from the moisture content, and it computes the convective flux anddiffusive enthalpy flux in moist air. The Liquid Water subnode defines the liquid water
saturation and velocity field, which is automatically set by the Heat and Moisturemultiphysics node if available.
The new Moist Porous Media multiphysics interface is found along with the Moist Air
and Building Materials interfaces under the Heat and Moisture Transport group in theHeat Transfer branch in the Model Wizard. It adds the new Moisture Transport in PorousMedia interface, the Heat Transfer in Moist Porous Media interface, and the Heat andMoisture multiphysics node.
The new Porous Media Flow multiphysics interface is found along with the Laminar Flow
multiphysics interface under the Heat and Moisture Flow group in the Heat Transfer
branch in the Model Wizard. It adds the Brinkman Equations interface; the new
Moisture Transport in Porous Media interface; the Heat Transfer in Moist Porous Media
interface; and the Moisture Flow, Heat and Moisture, and Nonisothermal Flow
multiphysics nodes.
The definition of the moisture variables has been updated in the Heat Transfer interface
to improve numerical accuracy in concentrated species conditions, when the airconcentration is small. This update affects the vapor mass fraction, the vapor
concentration, the moisture content, and the relative humidity variables.

136 |CHAPTER 1: RELEASE NOTESThe diffusive flux of thermal enthalpy is now accounted for when modeling coupledheat and moisture transport in moist air with the Heat and Moisture multiphysics
coupling node.
IMPROVEMENTS FOR PHASE TRANSPORT

The Phase Transport interface now supports pseudo time stepping. A Periodic
Condition and an Open Boundary condition, available on boundaries exterior to thePhase and Transport Properties feature, have also been added. The Phase Transportinterface now also provides improved support for deforming and rotating domains,
including the Interior Wall boundary condition.

New Models and Apps in Version 5.6
ANALYZING POROUS STRUCTURES ON THE MICROSCOPIC SCALE

Modeling flow through realistic porous structures is difficult due to the complexity ofthe structure itself. Resolving the flow field in detail is not feasible in real-life
applications. Therefore, macroscopic approaches are used, which utilize averaged
quantities of the porous structure, such as porosity and permeability. This example
analyzes the flow field at the pore scale in detail.
OPTIMIZATION OF A POROUS MICROCHANNEL HEAT SINKIn this example, the performance of a porous microchannel heat sink is optimized
using the Optimization Module. The optimum value of the thickness of the porous
substrate is calculated. This example is an extension of the model “Performance of a
Microchannel Heat Sink” and the results are compared with the results of theparameter study of the original model.

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Ray Optics Module
New Functionality in Version 5.6
IMPROVED RENDERING OF RAY TRAJECTORIESA new option for displaying a large number of rays in a Ray Trajectories plot is now
available. In the Extra Time Steps section, you can now select All from the Maximum
number of extra time steps rendered list. This new option will clearly display theintersection point of each ray, just as it reaches a boundary. The time to display the plot
also scales much better with the total number of rays in the plot and the total numberof intersection points, compared to the other options.
The new option All can also be selected for the Intersection Point 3D and Intersection
Point 2D datasets, allowing for fast and accurate evaluation of ray quantities at theintersection points with a sphere or plane.
OPTICAL SCATTERING IN DOMAINS

You can now model attenuation of rays due to scattering and absorption in a domain
containing small particles. Some typical examples include dust, smoke, and water
droplets in air, or small bubbles in water.
You can choose from different methods of computing the scattering and absorption
cross sections, depending on the size of the particles relative to the electromagnetic
wavelength. For very small particles, the Rayleigh theory can be used. A more generalapproach for somewhat larger particles is the Mie theory. Finally, some asymptotic
solutions for very large scattering particles are also available. The functions thatgenerate the scattering and extinction efficiency factors from the Mie scattering theory
are now built-in functions, called miescattering(n,x) and mieextinction(n,x),that can be used with any physics interface.
Optical extinction can either be modeled deterministically, with the ray intensity andpower falling off exponentially or randomly, with each ray having a probability ofextinction in any given time step. Built-in accumulated variables are also available tocollect the deposited energy due to absorption or the total energy lost due toextinction.

138 |CHAPTER 1: RELEASE NOTESSCATTERING AT RANDOM ROUGH SURFACES

A dedicated feature for modeling reflection and refraction at rough surfaces is now
available. You may specify diffuse or isotropic reflection and refraction at the surface,where the probability distribution of reflected and refracted ray direction does notdepend on the incident ray direction. Alternatively, you can specify a Rayleighroughness parameter, or surface slope error, that applies a random perturbation to thesurface normal and then applies Snell’s law and the Fresnel equations to the reflected
and refracted rays based on this perturbed normal direction. This allows for more
realistic modeling of lens surfaces that might not be perfectly smooth.
IDEAL LENS BOUNDARY CONDITION

A dedicated boundary condition is now available for treating flat surfaces as if they
were thin lenses of a specified optical power. This allows for some very quick,approximate ray optics simulations that don’t require a very detailed geometry or
material properties to be specified.
NEW OPTIONS FOR SPECIFYING REFRACTIVE INDEXThe options for specifying a refractive index in the Medium Properties node have beenreorganized. You can now choose to specify either the absolute index (with respect tovacuum) or the relative index (with respect to air) directly. For the relative index, you
specify the reference temperature and reference pressure at which the refractive index
of air is computed.

Backwards Compatibility
The old Medium Properties node settings (before version 5.6) have been mapped to the
new settings so as to give the same solution as in older versions. For example, the old
option Specify refractive index is now Specify absolute refractive index.
NEW CONE-BASED RELEASE: FLAT CONE IN 3D

When releasing rays in a conical distribution in 3D, you now have the option to releasea flat cone, essentially requiring all rays to lie in the same plane. You can control theorientation of the plane that the rays are held in.
In addition, for some other conical distributions, you now have finer control over thedefinition of the transverse directions to the cone axis. This can make a significant
difference when rays are released at specific azimuthal angles to this transverse
direction.

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RESET VACUUM WAVELENGTH OR FREQUENCY

At some boundary conditions, such as the Wall, you can now reset the vacuum
wavelength or frequency of rays. The new values can be specified directly or sampledfrom a normal, lognormal, or uniform distribution.
RANDOM SAMPLING OF WAVELENGTH AND FREQUENCY

When releasing polychromatic rays, you can now sample the vacuum wavelength or
frequency of the rays deterministically or randomly. In addition, if the model includes
any Auxiliary Dependent Variable nodes, you can sample the initial values of these extra
variables deterministically or randomly. In previous versions, these variables werealways sampled deterministically.
EASIER SAMPLING FROM UNIFORM DISTRIBUTIONSWhen releasing polychromatic rays, if you sample the vacuum wavelength or frequency
from a Uniform distribution, you can now specify the maximum and minimum values
in the distribution. Previously, you had to specify the mean and standard deviation.
This change also applies to any Auxiliary Dependent Variable nodes in the model.

Backwards Compatibility
When an older model is loaded into version 5.6, if the initial value of an Auxiliary
Dependent Variable, vacuum wavelength, or ray frequency was sampled from a Uniform
distribution, the minimum and maximum are automatically defined to give the same
result as in the older model:
New minimum = (Old mean) - (Old standard deviation)*sqrt(3)New maximum = (Old mean) + (Old standard deviation)*sqrt(3)NEW GEOMETRY PART: SPHERICAL POLYGONAL LENSThe Spherical Polygonal Lens can now be selected from the Part Library for the Ray
Optics Module. The lens surfaces can either be concave or convex, and the outer edge
can be a regular polygon with any number of vertices.

New Applications in Version 5.6
DOUBLE GAUSS LENS IMAGE SIMULATIONThis example extends the basic Double Gauss Lens tutorial by illustrating how the lenssystem creates an image. A bitmap is first loaded into the model and positioned at theobject plane. Rays are released from the object plane, and as they reach thecorresponding image plane, they reconstruct an image of the original object.

140 |CHAPTER 1: RELEASE NOTESPETZVAL LENS GEOMETRIC MODULATION TRANSFER FUNCTION

The example demonstrates how to use model methods to compute and plot the line
spread function (LSF) and the geometric modulation transfer function (MTF) of a
Petzval lens.

Important Fixes in Version 5.6
GRATINGS CONTRIBUTE TO THE REFLECTION COUNT

When using the built-in option to Count reflections in a model that uses the Grating or
Cross Grating node, the reflection counter is also incremented for the reflected rays ofall diffraction orders.
RELEASE FROM FAR FIELD WITH A WAVELENGTH DOMAIN STUDYThe Release from Far-Field Radiation Pattern node can now be used to release rays when
the far-field radiation pattern was computed using a Wavelength Domain study step.
Previously, only a Frequency Domain study step was supported.
PHASE SHIFT OF P-POLARIZED RAYS IN 2D

Previously a nonphysical phase shift was observed for reflected rays at a Material
Discontinuity with in-plane (p) polarization in 2D models. This has been corrected.
ILLUMINATED SURFACE WITH PHASE

Previously, the Illuminated Surface ray release feature would give an error if it was usedwhile the Compute phase check box was selected in the physics interface Additional
Variables section. This has been fixed.
In addition, the initialization of ray Stokes parameters from the Illuminated Surface has
been updated to be more consistent with the behavior of rays incident on walls andmaterial discontinuities.

Backward Compatibility with Version 5.5
ILLUMINATED SURFACE SETTINGS

Many of the settings for the Illuminated Surface ray release feature have been renamed.
However, in older models, the values of the variables with the old names will bemapped to the variables with the new names. In addition, the old names can still be
used in model methods in the Application Builder or in Model Java® files.

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Backward Compatibility with Version 5.4
HANDLING OF GRATING ORIENTATION DIRECTION

The handling of grating orientation was made more robust and consistent in version
5.5 compared to previous versions. Occasionally, this means that the directions
associated with positive and negative diffraction orders will appear reversed when
opening an older model in version 5.5 or newer.
To assist in the reassignment of any grating orientation directions, the direction
associated with positive diffraction orders will be indicated by an arrow in the Graphics
window.
RENAMED RAY RELEASE FEATURES

In version 5.5 the Inlet feature was renamed to Release from Boundary and the Inlet on
Axis feature was renamed to Release from Symmetry Axis.
RENAMED RAY STATISTICS

Since version 5.5 some variables for the ray statistics have been renamed. Here, <phys>is the physics identifier and <feat> is the tag of a ray release feature.
• <phys>.rmaxall has been renamed to <phys>.rmax.
• <phys>.rmidrms has been renamed to <phys>.rmrms.
• <phys>.<feat>.rmaxrel has been renamed to <phys>.<feat>.rmax.
• <phys>.<feat>.rmidrms has been renamed to <phys>.<feat>.rmrms.

Backward Compatibility with Version 5.3 and Earlier
DIFFRACTION GRATING SETTINGS MOVED TO A SUBNODE

In version 5.3 and earlier, the Grating feature for the Geometrical Optics interface
automatically released transmitted and reflected rays of diffraction order zero. In
version 5.3a, the rays of diffraction order zero are controlled by a Diffraction Ordersubnode, as are all other diffraction orders that might be released.
NEW OPTIONS FOR SPECIFYING DIFFRACTION GRATING ORIENTATIONIn the Grating feature for the Geometrical Optics interface, the options to control
grating orientation in 3D have been reorganized and expanded. It is now possible tospecify either the direction of the grating lines or the direction of periodicity in the142 |CHAPTER 1: RELEASE NOTES

grating surface. The input Grating orientation specification has been renamed Directionof grating lines.
NEW OPTIONS FOR SPECIFYING REFLECTANCE OR TRANSMITTANCE

In the Geometrical Optics interface, the settings to control Thin dielectric films on
boundary in the settings for the Material Discontinuity feature have been renamed andrearranged.
The old options Single layer, specified reflectance and Single layer, specified
transmittance have been renamed to Specify reflectance and Specify transmittance,

respectively. For both of these options and for the Anti-reflective coating option, which
has not been renamed, the Treat as single layer dielectric film check box is selected when
opening the model in version 5.3a. Otherwise, this check box is cleared, which is thedefault behavior.
ADJUSTMENT TO THE RAY TERMINATION FEATURE

In the Ray Termination feature for the Geometrical Optics interface, the Termination
criteria list has been renamed Additional termination criteria.
REMOVED CHECK BOXES FOR OBSOLETE FUNCTIONALITY

In the settings for the Geometrical Optics interface, the Allow propagation outside
selected domains check box has been removed. This check box was flagged as obsolete

in version 5.3, so clearing it would have created a Warning node.
In the Settings window for the Release from Grid feature, the check box Suppress
interaction with coinciding exterior boundaries has also been removed.

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RF Module
New Functionality in Version 5.6
ANALYZING THE RCS OF A CONDUCTIVE CONVEX-SHAPED OBJECTQUICKLY

When the scattered shape is mostly convex, such as a sphere, this new physics interface
can be used for quick studies of the far-field response of a 3D or 2D object to a given
background field. The physics interface sets up a surface electric background field forthe far-field transformation using the Stratton–Chu formula, performed in the
postprocessing.
SOLVING FOR FAST PORT SWEEPUse a new study step, Frequency Domain Source Sweep, to solve a frequency-domain
study that is sweeping among ports and lumped ports calculating a full S-parameter
matrix. The settings for this study step are similar to those for the Frequency Domain
study step and much simpler than the traditional port sweep, which requires aparametric sweep step.
PORT ENHANCEMENT

Numeric TEM impedance calculation can now be performed without defining themagnetic field integration line for the current. The port impedance is computed using
the average power flow on the port boundary and voltage calculated by the electricfield line integration. A transverse electromagnetic (TEM) type port supporting theuser-defined electric potential and ground boundaries is now available in 2D and 2D
axisymmetric models. Lumped port excitation can be configured by input power.
ADDITIONAL RF PART LIBRARY

Four new edge-launch connectors from Signal Microwave have been added in the RF
Module Part Library.
POLARIZATION PLOT TYPE

The Polarization plot type depicts the polarization state for the different diffraction
orders. It is available as a plot type in postprocessing and is used for default plots when
periodic ports are included in the simulation.

144 |CHAPTER 1: RELEASE NOTESSCATTERING BOUNDARY CONDITION CAN USE OBLIQUE ANGLE OF
INCIDENCE IN MODE ANALYSISThe Scattering boundary condition can now, for mode analysis, efficiently absorb
waves having a wave vector composed of the mode's propagation constant directed
tangentially to the boundary and a remaining normal component.
INPUT POWER TO CONTROL GAUSSIAN BEAM AMPLITUDEFor Gaussian beam background fields and input fields to the Scattering boundary
condition, the amplitude of the beam can be specified by providing the input power.
REFERENCE POINT CAN BE DEFINED BY A GENERAL EXPRESSION

The Reference point subfeature to the Scattering boundary condition can now also be
specified from a general vector expression.
SYNCHRONIZATION OF MATERIAL PARAMETERS BETWEEN DIFFERENTRELATED MATERIAL PROPERTY GROUPS

The relative permittivity, refractive index, loss tangent, and dielectric loss material
models can synchronize the material parameters between the groups. Thus, if amaterial is added and specified by the refractive index material property group, theElectric displacement field setting in the Wave equation node can be any of thementioned material models. If the required parameters are not directly available in thematerial, the parameters are created using a synchronization rule.
NEW CURL SHAPE FUNCTION

The Nédélec element of the second kind is implemented, having full polynomial orders
in all directions for each field component. This can, for some simulations, make theproblem solve for lower shape orders or with coarser meshes, and it can also make theresulting fields look smoother in postprocessing.

New and Updated Models in Version 5.6
THERMOSTRUCTURAL EFFECT OF A CAVITY FILTER

This example investigates the electrical performance of a cascaded cavity filter
operating in the millimeter-wave 5G band with temperature changes. The thermalvariations result in structural deformations of the structure. Thus, the resonant
frequencies of the filter elements (cavities) are affected by thermostructural
phenomena. S-parameters are computed with different thermal expansion
configurations.

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BASIC EMISSION AND IMMUNITY ANALYSIS OF A CIRCUIT BOARD

This example provides a walkthrough of how to simulate the basic radiated emissionof a printed circuit board and its immunity response from outside noise. First, when
one of the microstrip lines is excited, the crosstalk to an adjacent printed line and theradiated field, through an incomplete shield of a plastic enclosure, are computed forthe emission analysis. The second study reviews the impact on the circuit board when
there is the radiation from an antenna located outside the enclosure.
FAST ASYMPTOTIC RADAR CROSS-SECTION ANALYSIS OF A CONDUCTIVESPHERE

This example uses asymptotic techniques to study the radar cross-section (RCS)
response of a conductive sphere. The selected physics interface transforms the incident
plane-wave field on the boundaries to the far field using the Stratton–Chu formula.
The computed results are compared to the well-known asymptotic RCS value of aconductive sphere in the optical region.
MODELING OF A PHASED ARRAY ANTENNAThis example shows how to design a phased array with beam scanning functionality
based on the arithmetic phase difference between the array elements. The initial
complicated model can be reduced to a simple single unit cell model with periodic
conditions to make the analysis faster and more efficient. Two-phased array designs
built with microstrip patch antennas are studied and they are in good agreement of theantenna gain.

146 |CHAPTER 1: RELEASE NOTESRotordynamics Module
New Functionality in Version 5.6
MULTI-SPOOL BEARING

Using the new feature Multi-Spool Bearing, it is possible to model vibrations in coaxial
rotors running at different speeds. This feature models the intershaft bearing between
two coaxial shafts. Such rotors are common in steam turbines in power plants, where
the system consists of a sequence of turbines having coaxial rotors running at different
speeds. Another example of multispool rotors is in turbofan engines, where an innershaft having a low-pressure turbine drives the fan, and an outer shaft having a highpressure turbine drives the compressor.
SQUEEZE FILM DAMPER

Squeeze film dampers are components that provide additional damping to rotating
systems through squeezing of the fluid film. Often, these components are used
together with rolling element bearings, which do not offer enough damping on theirown. Fluid film dampers are, however, also used together with hydrodynamic bearings.
There are two ways to model squeeze film dampers:• By solving Reynolds equation for the pressure distribution in the film, thus
computing the net reaction forces and moments of the damper. For this type ofmodeling, the new feature Squeeze Film Damper is provided in the Hydrodynamic
Bearing interface.
• By using an analytical expression for the forces and moments of the damper
obtained using the short length approximation. For this type of modeling, you can
add a Squeeze Film Damper subnode to the Journal Bearing and Radial Roller Bearing
nodes in the Solid Rotor and Beam Rotor interfaces.
DYNAMIC COEFFICIENTS CALCULATION FOR HYDRODYNAMIC BEARINGS

Dynamic coefficients (that is, equivalent linear stiffness and damping coefficients about
an equilibrium location of the journal) can now be computed. The computation isenabled by selecting Calculate dynamic coefficients in the settings for the Hydrodynamic
Bearing interface. This is useful for bearing design where it is necessary to limit thecross-coefficients in the bearing to avoid instability. Also, dynamic coefficients can beused to run simplified rotor simulations to speed up the process.

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DEFAULT GEOMETRY PLOT FOR BEAM ROTOR INTERFACEA new default plot for the geometry of the rotor has been added in the Beam Rotor
interface. This helps in visualizing the location of the various components while
analyzing the results.
• A disk is shown as a thin circular plate.
• A radial bearing is shown as a cone in the radial direction pointing toward the rotor.
• Axial bearings at the end of the rotor are represented by cones in the axial direction.
If an axial bearing is located at the interior of the rotor, a small disk representing thecollar of the bearing is drawn together with two cones pointing toward the collar
from both sides.
There is also an option in the interface settings to include this graphical representationin the stress and whirl plots.
CHANGE ROTOR SPEED FEATURE IN BEAM ROTOR INTERFACEA new feature, Change Rotor Speed, has been added to the Beam Rotor interface toallow modeling multispool rotors that are running at different angular speeds.
FILM BOUNDARY CONDITION IN HYDRODYNAMIC BEARING

When cavitation is not modeled in detail, a new section, Film Boundary Condition, isadded for Hydrodynamic Journal Bearing, Floating Ring Bearing, and Hydrodynamic Thrust
Bearing nodes. There are two options: Sommerfeld and Gümbel. The Sommerfeld
condition works as before, so that the full film is used for the net force computation.
The Gümbel condition considers only the part of the film where the pressure is positive
for the net force computation. This facilitates approximate modeling of the cavitation
effect in the film.
AUTOMATIC SETTINGS FOR CAMPBELL PLOTIn earlier versions, to get the proper Campbell plot, it was necessary to select the Axis
Source Data as Outer solution for all the nodes in the Campbell plot manually. This is
now handled automatically and no further manual settings are needed to get a proper
Campbell plot.
FATIGUE ANALYSIS IN SOLID ROTOR INTERFACEIn the Fatigue interface, it is now also possible to perform fatigue analysis based on
results from the Solid Rotor interface. Fatigue analysis requires the Fatigue Module.

148 |CHAPTER 1: RELEASE NOTESNEW POSTPROCESSING VARIABLES IN HYDRODYNAMIC BEARING
INTERFACE

Several new postprocessing variables have been added in the Hydrodynamic Bearing
interface and are available in the results menus. These variables include minimum film
thickness, maximum pressure, total viscous heat loss, journal eccentricity, journal
relative eccentricity, and attitude angle.

New Models in Version 5.6
CRITICAL SPEED OF A DUAL ROTOR SYSTEM

An eigenfrequency analysis of a dual rotor system connected through a multispool
bearing is performed in this model. Cross-exciting vibrations through the multi-spool
bearings make the dynamic behavior of one shaft dependent on the dynamic behaviorof the other. Computed critical speeds are compared with values given in the literature.
EVALUATION OF THE DYNAMIC COEFFICIENTS OF A PLAIN JOURNAL
BEARING

When analyzing rotors, it is common that bearings are modeled through their effective
dynamic coefficients about a static equilibrium position. This example demonstrates
how to compute such coefficients for a plain journal bearing. Computed coefficientsare also compared with analytical values obtained from the solution of the Reynolds
equation for a short bearing approximation.
DAMPING COEFFICIENTS OF A SQUEEZE FILM DAMPER

Squeeze film dampers are components that provide additional damping to rotatingmachines. To simplify the modeling of a rotor assembly, squeeze film dampers are often
modeled in terms of their damping coefficients. In this model, damping coefficientsare computed for a short squeeze film damper and compared to analytical values.
SHAFT VIBRATION DUE TO GEAR RATTLE AND BEARING MISALIGNMENT

In a gearbox, vibrations due to rattling of the gears and bearing misalignments are
well-known sources of noise. In this example, two shafts connected through a pair ofgears are considered. The driver rotates at varying speed. Due to backlash in the gears,
the teeth meshing becomes intermittent, thus causing vibration in the shafts. Aftersome time, the driven shaft is loaded with a torque, making the teeth meshing in gears
smooth. In order to analyze the effect of the misalignment on the rotor vibrations, atime-dependent analysis is performed for two cases. In the first case, all bearings arealigned with the shafts, and in the second case, one of the bearings has a small angular

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misalignment. The results show larger torsional and axial vibrations in the shaft in thepresence of misalignment.

150 |CHAPTER 1: RELEASE NOTESSemiconductor Module
New Functionality in Version 5.6
MULTICOMPONENT WAVE FUNCTION

The Schrödinger Equation interface has been expanded to support multicomponent
wave functions. This new capability allows the straightforward modeling of multiband
systems and particles with spins.
TENSOR EFFECTIVE MASSThe Schrödinger Equation interface now supports tensor effective masses.
LORENTZ FORCE

This new feature for the Schrödinger Equation interface adds the contribution to thekinetic momentum from the magnetic vector potential.
ROTATING FRAME

This new feature for the Schrödinger Equation interface adds the additional
contribution to the Hamiltonian in a rotating frame.
DISSIPATIONThis new feature for the Schrödinger Equation interface adds dissipation for timedependent systems.
FINITE VOLUME FORMULATION• Improved accuracy of models with curved boundaries by switching from geometry
normal vectors to mesh normal vectors.
• Improved electrostatic terminal boundary condition with nonuniform applied
voltage by using the circumcenter operator on the boundary.
• Improved charge carrier constraint values on metal contacts by using thecircumcenter operator on the boundary.
DRIFT-DIFFUSION FORMULATION

Expanded the drift-diffusion formulation for graded materials to include the effect ofcontinuously varying effective density of states. (The quasi-Fermi level formulation
already included this.)

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IMPACT IONIZATION

Impact ionization: A new option of indirectly updating the generation rate is added,
to combine with the Previous Solution node in the solver sequence to improve
convergence by delaying the update of the generation rate. This allows the use ofstationary study steps instead of the time-dependent study step, which was required inprevious versions.
MODEL UPDATES• The model gaas_pin_photodiode has been updated, using global evaluations todemonstrate the consistency between the input optical power and the output
electrical current (conservation of particles).
• The model pin_reverse_recovery has been updated to take advantage of the
improved circuit interface.
• A fully analytic formula for the Thomas–Fermi approximation is added to the modelgross_pitaevskii_equation_for_bose_einstein_condensation.
CORRECTIONS AND BACKWARD COMPATIBILITY

The safeguard against square roots of negative numbers is updated.

New Models in Version 5.6
K • P METHOD FOR STRAINED WURTZITE GAN BAND STRUCTURE

This benchmark model computes the valence band structure of an unstrained and astrained bulk GaN wurtzite crystal, as a tutorial for users who wish to set up multiple
wave function components with the Schrödinger Equation interface. The model
follows the formulation given in the reference paper by Chuang and Chang. The
diagonal and off-diagonal elements of the Hamiltonian matrix are entered using builtin features, with detailed instructions in the model documentation. The computed
eigenvalues agree well with the analytic solution and Fig. 5 in the paper.
A SILICON QUANTUM DOT IN A UNIFORM MAGNETIC FIELD

This tutorial model solves a two-component Schrödinger equation for the eigenstatesof a simple silicon quantum dot in a uniform magnetic field, based on the paper by Jockand others on the topic of spin-orbit qubits. The built-in domain condition Lorentz
Force for the Schrödinger Equation interface is used to account for the contribution
to the kinetic momentum from the vector potential. The coupling of the spin-up andspin-down components is implemented using the built-in domain condition Zeroth
Order Hamiltonian. Together with the benchmark model k dot p Method for Strained

152 |CHAPTER 1: RELEASE NOTESWurtzite GaN Band Structure, these examples show how to set up multiple wavefunction components with the Schrödinger Equation interface. The computed
probability density and kinetic momentum density of the ground state compare wellwith Supplementary Figure 1 in the paper. In addition, the computed energy
difference between the first two eigenstates agrees well with the expected value froman intuitive analytic calculation.
VORTEX LATTICE FORMATION IN A ROTATING BOSE-EINSTEIN
CONDENSATEThis tutorial model solves the Gross–Pitaevskii equation for the vortex lattice
formation in a rotating Bose–Einstein condensate bound by a harmonic trap. The
equation is essentially a nonlinear single-particle Schrödinger equation, with theinterparticle interaction represented by a potential energy contribution in proportion
to the local particle density. The time evolution in the rotating frame withphenomenological damping is configured with built-in features of the Schrödinger
Equation physics interface. Nucleation of vortices is seen starting at the periphery of
the condensate. Subsequently, the system goes through a period of spectacular
dynamical instability before settling down in the low-energy state of a vortex lattice.
The Optimization Module is used for parameter estimation from the numerical results.
The time scales of the initial oscillation and the eventual collapse of the ellipticity
parameter agree well between simulation and the experimental data published by
Madison and others.

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Structural Mechanics Module
New Functionality in Version 5.6
EMBEDDED REINFORCEMENTS

A new multiphysics coupling Embedded Reinforcement has been added. It can be used
to insert edge elements from the Truss or Beam interfaces, as well as surface elementsfrom the Membrane interface, into a domain modeled with Solid Mechanics. The
mesh in the lower-dimensional interface is independent of the domain mesh. The
purpose is to model structures like embedded reinforcements, sensors, etc.
The connection can be fully rigid or flexible. You can also model debonding between
the embedded element and the surrounding solid.
FERROELECTROELASTICITY MULTIPHYSICS INTERFACEThe new Ferroelectroelasticity multiphysics interface is intended for analysis offerroelectric materials. These materials exhibit nonlinear piezoelectric properties. This
interface will add Solid Mechanics and Electrostatics interfaces together with the new
Electrostriction multiphysics coupling. In Electrostatics, the new Charge Conservation,
Ferroelectric material model is used. In this material, it is possible to model, forexample, hysteresis using a Jiles–Atherton model.
This multiphysics interface requires the MEMS Module or the AC/DC Module.
ELECTROSTRICTION MULTIPHYSICS INTERFACE

With the new Electrostriction multiphysics interface, you can model electrostriction
phenomena; that is, a situation where a strain proportional to the square of thepolarization is induced by an electric field. This interface will add Solid Mechanics andElectrostatics interfaces together with the new Electrostriction multiphysics coupling.
In Electrostatics, the standard Charge Conservation material model is used.
This multiphysics interface requires the MEMS Module or the AC/DC Module.
TRANSITION MULTIPHYSICS COUPLINGS FOR PIPE MECHANICS

The new multiphysics coupling Structure-Pipe Connection has been added forfacilitating transitions from the Pipe Mechanics interface to the Shell and Solid
Mechanics physics interfaces. The purpose is to switch between the line representation

154 |CHAPTER 1: RELEASE NOTES

in the Pipe Mechanics interfaces to a more accurate 3D representation where there aretransitions in the pipe geometry.
FLUID-PIPE INTERACTION, FIXED GEOMETRY MULTIPHYSICSINTERFACE

The new Fluid-Pipe Interaction, Fixed Geometry interface connects the Pipe Flow andPipe Mechanics interfaces, in order to transfer fluid loads to the structural analysis. The
new Fluid-Pipe Interaction multiphysics coupling is used. Internal pressure, drag forces,
loads on bends, and loads on junctions can be taken into account.
This multiphysics interface requires the Pipe Flow Module.
SPRINGS AND DAMPERS CONNECTING POINTSIn all structural mechanics interfaces, a new feature called Spring-Damper has been
added. With it, you can connect two points with a spring and/or a damper. The points
can be geometrical points, but they can also be abstract through the use of, forexample, attachments or direct connections to rigid bodies. The spring can either bephysical, with a force acting along the line between the two points, or described by afull matrix, connecting all translational and rotational degrees of freedom in the twopoints. The feature also makes it possible to connect a spring between points in two
different physics interfaces.
CRACK MODELINGThe new Crack node in Solid Mechanics can be used for different types of fracture
mechanics simulations. When applied to an internal boundary, the two sides become
disconnected. A crack can either be ideal or modeled with separate faces in thegeometry. Through the addition of the J-integral subnode, it is possible to compute Jintegrals and stress intensity factors in 2D, 2D axisymmetry, and 3D. A special Face
Load subnode is available for prescribing a load on the crack faces.
PORT BOUNDARY CONDITION FOR ELASTIC WAVE PROPAGATIONThe new Port boundary condition, available with the Solid Mechanics interface, isdesigned to excite and absorb elastic waves that enter or leave solid waveguidestructures. A given Port condition supports one specific propagating mode.
Combining several Port conditions on the same boundary allows a consistenttreatment of a mixture of propagating waves; for example, longitudinal, torsional, andtransverse modes. The combined setup with several Port conditions provides a superior
nonreflecting condition for waveguides to, for example, a perfectly matched layer(PML) configuration or the Low-Reflecting Boundary. The Port condition supports

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S-parameter (scattering parameter) calculation, but it can also be used as a source tojust excite a system. The power of reflected and transmitted waves is available inpostprocessing. To compute and identify the propagating modes, the Boundary Mode
Analysis study is available in combination with the Port conditions.
GENERALIZED PLANE STRAIN WITHOUT BENDING

When using generalized plane strain for 2D Solid Mechanics, it is now possible tochoose that the out-of-plane strain is limited to be constant over the cross section. You
control this behavior through the new Enable out-of-plane bending check box in the 2D
Approximation section in the settings for the Solid Mechanics interface.
NEW OPTION FOR PRESCRIBING ROTATING FRAME SPEED

In the Rotating Frame node in the Solid Mechanics and Multibody Dynamics interfaces,
the new option Rigid body has been added. With this option, you enter a timedependent torque around the axis of rotation, and the rotational velocity is computed
by integration of the rigid body equation of motion.
ACTIVATION OF MATERIAL IN THE TRUSS INTERFACE

It is now possible to activate and deactivate a material in the Truss interface by adding
the Activation subnode under Linear Elastic Material. This can be used to simulate
construction processes where bars are added at different stages.
RIGID CONNECTOR IMPROVEMENTS

The Rigid Connector features have a set of improvements:• In the Shell and Beam interfaces, the selection alternatives have been extended also
to the top level (that is, boundaries and edges, respectively).
• When the center of rotation is defined by a point selection, the point no longer has
to be part of the physics interface itself.
• It is possible to couple rigid connectors from different physics interfaces, thus
defining a new type of virtual rigid object. This selection resides in the Advanced
section of the settings for the rigid connector.
• In the Solid Mechanics, Shell, and Beam interfaces, it is possible to automaticallygenerate rigid connectors from RBE2 elements in an imported file in the Nastran®
format. This is controlled from a section named Automatic Modeling in the settings
for these interfaces. Rigid connectors created can belong to several physics interfaces
in order to mimic the connections in the imported file.

156 |CHAPTER 1: RELEASE NOTESUNIDIRECTIONAL CONSTRAINTS FOR BEAMS AND PIPESIn the Beam and Pipe Mechanics interfaces, the Prescribed Displacement/Rotation node
has been augmented with an option called Limited Displacement. When this option is
selected, you can define an upper and lower limit for the displacement. In particular,
this facilitates the modeling on beams resting on unidirectional supports.
This option is available for constraints on points, as well as for constraints on edges.
IMPROVED DYNAMIC CONTACT

New algorithms have been introduced in order to improve the conservation of
momentum and energy during transient contact events. These can be activated by
selecting either the Penalty, dynamic or Augmented Lagrangian, dynamic formulation in
the Contact node.
MORE OPTIONS FOR PENALTY FACTORS IN CONTACT

When using the penalty method for contact analysis, there are three new options in theContact and Friction nodes for controlling the value of the penalty factor: Automatic,
soft, Manual tuning, and Nonlinear.
When using the augmented Lagrangian method with a preset penalty factor, there is
one new option: Bending. The purpose is to provide a softer penalty factor that canstabilize the iterations for bending-dominated problems.
FULLY COUPLED SOLUTION METHOD FOR AUGMENTED LAGRANGIANMETHOD IN CONTACT

It is now possible to use a fully coupled solver together with the augmented
Lagrangian contact algorithm. This makes it easier to set up solver sequences and may
also improve stability and convergence for some problems. The new formulation,
allowing a fully coupled solver, is selected in the Solution method list in the settings for
the Contact node.
USER DEFINED FRICTION MODEL

In the Friction node under Contact, you can now also select User defined as the Friction
model. In this case, you directly enter an expression for the tangential force that causes
sliding in terms of any other variables.
FRICTION WITH A KNOWN SLIDING VELOCITY

In some applications, the direction of the friction force is known, because two objects
are sliding on each other with a given relative velocity. In this case, it is not necessary
to solve for the friction forces. Such an approach can speed up the solution

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significantly. The new Slip Velocity node, added under Contact, can be used whenmodeling such cases. The inputs for this node are similar to those of the Friction node.
WEAR MODELING

Methods for modeling mechanical wear have been added. This is controlled from the
new Wear node, a subnode under Contact available in the Solid Mechanics andMultibody Dynamics interfaces.
There are two algorithms for wear modeling. In the more general, allowing arbitrarygeometry changes due to the wear, a deformed geometry approach is used. There isalso a simplified approach in which the wear is incorporated into the offset in thecontact gap.
COMPUTING ROTATION FROM DISPLACEMENTS

In physics interfaces that have displacements as degrees of freedom, it is sometimes
necessary to study the rotation of a region. To do that, you can add the new Average
Rotation node, which uses the displacements of a set of points to determine a rotation.
If more than three points are given, a least squares scheme is applied to make the best
approximation of a rigid body rotation for the entire set of points. In addition, angularvelocities and accelerations can be computed.
EVALUATING LOCAL BUCKLING IN TRUSS STRUCTURES

A set of variables, representing the safety margin against local buckling in truss
structures, has been added. You provide input data for such an evaluation in the newsection Local Buckling in the settings for the Cross-Section Data node.
NEW VISCOELASTICITY MODELSTwo new viscoelasticity models have been added: Maxwell and Generalized Kelvin–
Voigt.
The Maxwell material can be considered as a type of liquid, since its long-term
deformation under a constant stress is unbounded.
The Generalized Kelvin–Voigt model has a Prony series representation with several
time constants. Conceptually, it consists of a set of Kelvin elements (spring anddashpot elements in parallel) connected in series.

158 |CHAPTER 1: RELEASE NOTESFRACTIONAL DERIVATIVE VISCOELASTICITY

For frequency-domain analysis, all the viscoelasticity models (Generalized Maxwell,
Generalized Kelvin-Voigt, Maxwell, Kelvin-Voigt, Standard linear solid, and Burgers)
have been augmented by a fractional derivative representation.
Using a fractional time derivative representation makes it easier to fit material data toexperiments for some materials.
NEW TEMPERATURE SHIFT FUNCTION IN VISCOELASTICITYThe Tool–Narayanaswamy–Moynihan shift function is commonly used to describe theglass transition temperature in glasses and polymers. It has been added to the set ofshift functions in the Viscoelasticity node.
PERFORMANCE IMPROVEMENTS FOR VISCOELASTICITY

For time-domain analysis using the Generalized Maxwell and Standard Linear Solidviscoelastic models, performance has been improved by up to one order of magnitude.
The viscoelastic stresses are no longer represented by ordinary shape functions butwith state variables in the Gauss points.
DIRECT INPUT OF SECTION STIFFNESS IN BEAM

A new material model, Section Stiffness, has been introduced in the Beam interface.
Here, you directly enter data such as axial stiffness and bending stiffness. The purposeof this material model is to facilitate modeling of complex beam cross sections where
the stiffness properties cannot be deduced from a single elastic material and thegeometrical properties of the cross section. This is the case for composite beams, forexample.
TIMOSHENKO THEORY AS DEFAULT FORMULATION IN PIPE MECHANICS

The default beam theory formulation used in the Pipe Mechanics interface has beenchanged from Euler–Bernoulli to Timoshenko. The latter formulation, which includes
shear deformations, is more relevant for the majority of piping systems.
ANALYSIS OF LARGE DEFORMATION PROBLEMS IN AN UPDATED FRAME

When analyzing problems with large deformations, it is now possible to do so in amanner where the material frame is updated between each parameter value. A
deformed geometry approach is used, and the deformation implicit in thetransformation between the two frames is injected as a prestrain in the material modelin the updated geometry. To enable this functionality, you add an Elastic
Predeformation node.

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STRAIN FIELD CONSISTENT INTERPOLATION OF INELASTIC STRAINCONTRIBUTIONS

Several physical interactions, for example, thermal expansion and hygroscopic swelling,cause inelastic strains that are incorporated in the material models. If such strain fields
vary too much over an element, spurious artifacts can be seen in the resulting stressfields. In version 5.6, this is taken care of by a reinterpolation, so that the external strain
field has a polynomial order that matches the total strains computed from thedisplacements. In particular, this means that in a multiphysics analysis, thediscretization orders in the two participating interfaces can be chosen independently,
without considering consistency.
As an effect, the Thermal Stress, Solid and Joule Heating and Thermal Expansion
multiphysics interface no longer reduce the discretization order of the Heat Transfer
in Solids interface.
NEW WEAK EQUATION FOR GEOMETRIC NONLINEARITY

The weak contribution used for building the stiffness matrices in a geometricallynonlinear study step has been changed for some of the material models in the Solid
Mechanics interface. The new formulation, which is based on 1st Piola–Kirchhoff
stresses and variation of the deformation gradients, results in shorter assembly times.
HARMONIC PERTURBATION FOR GRAVITYThe Gravity node in the structural mechanics interfaces now has the Harmonic
Perturbation option. This is useful when a support excitation is transformed into aframe acceleration.
SOLVER SETTINGS CONTROL FOR ELASTIC WAVES

In the settings for the Solid Mechanics interface, a new section Transient Solver Settings
has been added. The purpose is to generate appropriate solver settings when analyzing
wave propagation problems in the time domain.
DEFAULT PLOT IMPROVEMENTS

There are some changes in the default plot generation:• When Safety nodes are present in one of the structural mechanics interfaces, default
plots showing failure indices will automatically be created.

160 |CHAPTER 1: RELEASE NOTES• The default plots in the Plate interface make use of the new Embed 2D dataset. This
makes it possible to show a 3D representation of, for example, the out-of-plane
displacements. Also, default load plots have been added using this technique.
• The default plots for Layered Linear Elastic Material in the Shell and Membraneinterfaces have been improved.
ONE-WAY FLUID-STRUCTURE INTERACTION STUDIES REMOVEDStudies of the one-way fluid-structure interaction type can no longer be added fromthe Add Study wizard. This does not affect studies already added in existing models.
The documentation has been augmented with instructions for how to set up suchstudies manually for different use cases. This allows for more flexibility than theprevious predefined studies could provide.
DISABLING OF WARPING EQUATIONS IN SOLID-BEAM CONNECTION

When the Solid-Beam Connection multiphysics coupling is used with the Solid boundaries
to beam points, transition option, it is now possible to suppress the equations used forcomputing the warping displacement on the boundary of the solid. This can simplify
solver setup for cases when the warping is negligible or nonexistent, for example, on
circular sections.
IMPROVED PRESSURE LOAD FOR SHELLSWhen using a pressure load in the Shell interface under geometric nonlinearity,changes in area due to local stretching are now taken into account.
VISCOUS DAMPING IN LAYERED LINEAR ELASTIC MATERIAL

The possibility to add viscous damping has been added to the Damping subnode under
the Layered Linear Elastic Material in the Shell interface.
IMPROVED SYMMETRY AND ANTISYMMETRY CONDITIONS IN MEMBRANE

The Symmetry and Antisymmetry conditions in the Membrane interface now provide
the possibility to select a coordinate system for more exact determination of thesymmetry plane. The options are identical to what is already present in thecorresponding nodes in the Shell interface.
CHANGES IN GEOMETRIC NONLINEARITY FOR BEAM AND PIPEMECHANICS

In the Beam and Pipe Mechanics interfaces, there is no formulation for prestressed
dynamic analysis. In previous versions, an attempt to do such an analysis was stopped
with an error message. This has been changed to a warning, since there are situations

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where such an analysis is meaningful. This is the case when the only source of stressstiffening comes from another physics interface, and it is thus now possible to conduct
such studies.
ITEMS MOVED IN CONTEXT MENUS

Some less used features in the structural mechanics interfaces have been moved down
into the More submenus in the context menus in order to reduce the size of the menus.
These items are:
• Initial Values• Change Thickness• Cell Periodicity• Low Reflecting Boundary
In addition, some new features reside in the More submenus:• Elastic Predeformation• Crack• PortOPTION FOR SOLVING FOR OUT-OF-PLANE STRAINS IN SHELL MOVED

The check box Solve for out-of-plane strain components in the Shell and Plate interfaces
has been moved from the interface level to the settings for the individual material
models.
CHANGED SHAPE FUNCTIONS IN AXISYMMETRIC SHELL

In the Shell interface in 2D axisymmetry, the shape functions for the out-of-planestrains are now of the type Discontinuous Lagrange.
POINT SELECTION CHANGED FOR BEAM END RELEASE

The point selection in Beam End Release has been changed so that it only allows
selection of a single point. This will not introduce a limitation, since a selection ofmultiple points was not meaningful.

New and Updated Models in Version 5.6
BRACKET — GENERAL PERIODIC DYNAMIC ANALYSISThis is a new example in the tutorial series showing various types of analyses of abracket. In this case, the loading is periodic, but not harmonic. The approach used

162 |CHAPTER 1: RELEASE NOTES

consists of computing a Fourier series representing the excitation, and then performing
a frequency sweep using the coefficients of the Fourier series as the frequencydependent loads. The set of harmonic solutions are superimposed to give the timedomain solution for one period of the excitation. Finally, a modal time-dependent
analysis over a large number of cycles is also performed, and the results of the two
approaches are compared.
DISC BRAKE PAD WEAR

In this example, wear of the friction material in a disc brake is studied. Quasistatic
friction forces are prescribed from simple kinematic considerations. The geometry of
the brake pad is continuously updated to account for the material removal due to wear
following the well-known Archard equation. Both the contact pressure and the wear
rate changes over time as an effect of the updated pad geometry.
IMPACT BETWEEN TWO SOFT RINGSIn this conceptual example, the soft impact between two elastic rings is modeled using
the Solid Mechanics interface. One of the rings is given an initial velocity to initiate theimpact event. Both rings are unconstrained and not subjected to any external forces.
Contact is modeled using a viscous formulation with both the penalty and augmented
Lagrangian techniques. The conservation of linear and angular momentum as well as
energy is verified.
ANGLE CRACK EMBEDDED IN A PLATE

This example reproduces a NAFEMS benchmark in which a plate with an angle crack
is subjected to tensile loading. The J-integral is calculated and the stress intensity
factors for Mode I and Mode II are compared to the benchmark results for several
values of the angle.
SURFACE CRACKED CYLINDER

In this benchmark example, a semi-elliptical crack at the inner surface of a cylinder isstudied. The inside of the cylinder and the crack faces are subjected to a pressure load.
The J-integral is calculated along the crack front, and the stress intensity factor is thencompared with the reference values.
MECHANICAL MULTIPORT SYSTEM: ELASTIC WAVE PROPAGATION IN A
SMALL ALUMINUM PLATE

In this tutorial, the vibrational behavior of a small aluminum plate with four waveguidestructures is analyzed. This is an example of a structural component located in a device
where elastic waves are propagating, like a smart speaker, an electric motor, or a MEMS

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device. The plate can be thought of as a mechanical multiport system. The model uses
the Port boundary condition at the inlet/outlet of the waveguide structures. The Port
conditions consistently capture and treat the different propagating elastic modes likelongitudinal, transverse, and torsional waves. The transmission and reflection of thevarious modes are characterized through the scattering matrix of the system, which iscomputed automatically. This allows the vibrational behavior of the component to be
characterized in great detail, for example, for subsequent use in a system simulation.
HYSTERESIS IN PIEZOELECTRIC CERAMICS

Many piezoelectric materials are ferroelectric. Ferroelectric materials exhibit nonlinear
polarization behavior such as hysteresis and saturation at large applied electric fields.
In addition, the polarization and mechanical deformations in such materials can bestrongly coupled due to the electrostriction effect. This model uses the
Ferroelectroelasticity interface to analyze a simple actuator made of PZT piezoelectric
ceramic material, which is subjected to an applied electric field and mechanical load.
SINGLE EDGE CRACK

This is a significantly updated version of an existing model, where an edge crack in aplate is studied. The new Crack and J-integral nodes are used, and different evaluation
options are compared.

164 |CHAPTER 1: RELEASE NOTES

Subsurface Flow Module
New Functionality in Version 5.6
NEW SHALLOW WATER EQUATIONS, TIME EXPLICIT INTERFACEThe Shallow Water Equations, Time Explicit interface is used for modeling flow below afree surface under the condition that the horizontal length scale in the model is muchgreater than the vertical depth between the free surface and the bottom topography.
The physics interface solves the shallow water equations obtained by depth averaging
the Navier–Stokes equations. The dependent variables are the water depth and water
flux. The interface is based on the discontinuous Galerkin method (dG-FEM) and uses
a time-explicit solver.
NEW ADD-IN FOR CREATING DISCRETE FRACTURE NETWORKS (DFN)

Fracture networks are important for groundwater flow, geothermal and petroleum
applications, nuclear waste storage, and more. A new add-in method is available forcreating discrete fracture networks (DFN) in realistic geometries, such as of reservoirs
and rock formations. The add-in works for both 2D and 3D geometries.
REVAMPED POROUS MEDIA FEATURES FOR TRANSPORT OF DILUTED
SPECIESThe Transport of Diluted Species in Porous Media interface, used to study the flow andchemical composition of fluids moving through the interstices of a porous medium, isrevamped to use the new Porous Material node.
Two new domain features, the Porous Medium and the Unsaturated Porous Medium
nodes, are available in the Transport of Diluted Species in Porous Media interface andTransport of Diluted Species interfaces and include support for using the new Porous
Material node for assigning material properties to the multiple phases in a porous
medium. The new nodes have subnodes to define the properties for the Liquid, Gas,
and Porous Matrix. The subnodes follow the same structure as the subnodes available
in the Porous Material.
The check boxes Dispersion and Volatilization in partially saturated porous media havebeen removed from the Transport Mechanisms settings. This functionality is now
available in the subnodes of the new Porous Medium and Unsaturated Porous Medium
nodes.

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The new nodes replace the previously available Porous Media Transport Properties andPartially Saturated Porous Media nodes. These node are kept when opening a model
created in a previous version.
REVAMPED POROUS MEDIA FEATURES FOR HEAT TRANSFER

The Porous Medium feature is now always available without having to select the Heattransfer in porous media check box, which has been removed.

The Porous Medium node has been revamped. The solid and fluid phases are now
handled in dedicated subnodes, namely the Porous Matrix and Fluid nodes. The
computation of the effective material properties is handled in the Porous Medium node,
whereas the solid and fluid properties are defined in the Porous Matrix and Fluid
subnodes. It is also possible to account for an additional immobile fluid phase byadding the Immobile Fluids subnode under the Porous Medium node.
In the new Porous Medium node, the settings are homogenized with those of theporous media features in the fluid flow and chemical species transport interfaces. In
particular, the Porosity is specified instead of the Volume fraction of the solid phase. In
addition, it is possible to set either the Dry bulk properties or the Solid phase properties,
depending on the availability of these material properties.
The new design allows to take advantage of the new Porous Material functionality under
the Materials node, in which the porosity and volume fractions may be set, and wherematerial properties are set in subnodes dedicated to each phase: Solid, Fluid, andImmobile Fluid.
IMPROVEMENTS FOR PHASE TRANSPORT

The Phase Transport interface now supports pseudo time stepping. Periodic
Condition and Open Boundary conditions, available on boundaries exterior to thePhase and Transport Properties feature, have also been added. The Phase Transportinterface now also provides improved support for deforming and rotating domains,
including the Interior Wall boundary condition.

New Models in Version 5.6
ANALYZING POROUS STRUCTURES ON THE MICROSCOPIC SCALE

Modeling flow through realistic porous structures is difficult due to the complexity ofthe structure itself. Resolving the flow field in detail is not feasible in real-life
applications. Therefore, macroscopic approaches are used, which utilize averaged

166 |CHAPTER 1: RELEASE NOTESquantities of the porous structure, such as porosity and permeability. This example
analyzes the flow field at the pore scale in detail.
DAM BREAKING ON A COLUMNThis transient model solves the shallow water equations to model the impact of a water
wave on a column. A body of water with a height of 0.3 meters is initially contained
behind a gate. At the start of the simulation, the gate is suddenly released and the bodyof water forms a wave moving toward the structure. After impacting on the structure,
the water continues until it is reflected at the wall of the tank and impinges a second
time on the column. The pressure force on the column is calculated and can becompared with experimental results.
TSUNAMI RUNUP ONTO A COMPLEX 3D BEACH, MONAI VALLEY

This example is an established benchmark case that models a scaled laboratory
experiment of the tsunami runup in the Monai Valley in Japan. The benchmark focuses
on a region near the shoreline for which detailed experimental data is available. The
tank is initially filled with still water, and a known incident wave is imposed at one of
the boundaries. The wave makes the shoreline move back and forth, eventually
covering the small island in the middle of the domain.
FLOW IN A FRACTURED RESERVOIRThis model demonstrates how to model flow through a fractured reservoir. The
reservoir is modeled with a discrete fracture network (DFN) where the fractures havea random distribution of position, size, orientation, and aperture.

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Wave Optics Module
New Functionality in Version 5.6
SOLVING FOR FAST PORT SWEEPS

Use a new study step, Frequency Domain Source Sweep, to efficiently solve a
frequency-domain study that is sweeping among ports calculating a full S-parameter
matrix. The settings for this study step are similar to those for the Frequency Domain
study step and much simpler than the traditional port sweep, which requires aparametric sweep step.
TIME TO FREQUENCY FFT STUDY FOR THE ELECTROMAGNETIC WAVES,
TRANSIENT INTERFACE

Use the Time to Frequency FFT study type to first make a broadband transient study.
Then the time-domain data is transformed to the frequency domain using a fast
Fourier transform (FFT). This study type is now available for the Electromagnetic
Waves, Transient interface.
POLARIZATION PLOT TYPE

The Polarization plot type depicts the polarization state for the different diffraction
orders. It is available as a plot type in postprocessing and is used for default plots when
periodic ports are included in the simulation.
SCATTERING BOUNDARY CONDITION CAN USE OBLIQUE ANGLE OF
INCIDENCE IN MODE ANALYSISThe Scattering boundary condition can now, for mode analysis, efficiently absorb
waves having a wave vector composed of the mode's propagation constant directed
tangentially to the boundary and a remaining normal component.
INPUT POWER TO CONTROL GAUSSIAN BEAM AMPLITUDEFor Gaussian beam background fields and input fields to the Scattering and Matchedboundary conditions, the amplitude of the beam can be specified by providing the
input power.
REFERENCE POINT CAN BE DEFINED BY A GENERAL EXPRESSION

The Reference point subfeature to Scattering and Matched boundary conditions can
now also be specified from a general vector expression.

168 |CHAPTER 1: RELEASE NOTESSYNCHRONIZATION OF MATERIAL PARAMETERS BETWEEN DIFFERENTRELATED MATERIAL PROPERTY GROUPS

The relative permittivity, refractive index, loss tangent, and dielectric loss material
models can synchronize the material parameters between the groups. Thus, if amaterial is added and specified by the refractive index material property group, theElectric displacement field setting in the Wave Equation node can be any of thementioned material models. If the required parameters are not directly available in thematerial, the parameters are created using a synchronization rule.
NEW CURL SHAPE FUNCTION

The Nédélec element of the second kind is implemented, having full polynomial orders
in all direction for each field component. This can, for some simulations, make theproblem solve for lower shape orders or with coarser meshes, and it can also make theresulting fields look smoother in postprocessing.

New and Updated Models in Version 5.6
THRESHOLD GAIN CALCULATIONS FOR VERTICAL-CAVITY SURFACEEMITTING LASERS (VCSELS)

An eigenfrequency study is used to find the resonance frequency and threshold gain
for an oxide-confined, GaAs-based, vertical-cavity surface-emitting laser (VCSEL).
The simulations are performed in two steps. A regular eigenfrequency analysis is first
performed to find good initial values for the subsequent nonlinear eigenfrequency
analysis.
The resonance frequencies and threshold gain, calculated for different device
geometries, compare well to values from a paper collecting the results from different
computational methods on this benchmark problem.
LEAKY MODES IN A MICROSTRUCTURED OPTICAL FIBER

A mode analysis study is used to find the complex effective indices for a
microstructured optical fiber (MOF), consisting of air holes in a silica host. As theeffective index is smaller than the refractive index of the silica background material, themodes are leaky.
The example demonstrates both the use of a perfectly matched layer (PML) and theuse of the Scattering boundary condition, using an oblique angle of incidence, totruncate the simulation domain.

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The real and imaginary parts of the effective index compare well to values from apublished paper.
TIME DOMAIN TO FREQUENCY FFT ANALYSIS OF A DISTRIBUTED BRAGG
REFLECTOR

This example demonstrates how to setup a Time Domain to Frequency FFT study fora distributed Bragg reflector (DBR) structure.
The results agree well with the results of a regular Frequency Domain study.
FABRY-PEROT RESONATORA Fabry–Perot resonator is a fundamental optical device and has a broad range ofapplications. Examples include measuring length, frequency, or wavelength andfiltering specific spatial modes. This example uses the Electromagnetic Waves, Beam
Envelopes interface in the bidirectional formulation to efficiently compute the modeshape and reflection/transmission properties of a macroscopic Fabry–Perot resonator.
This model replaces the Fabry–Perot Cavity model in the Wave Optics Module’s
Application Library.
OPTIMIZATION OF A PHOTONIC CRYSTAL FOR SIGNAL FILTERING

This example builds on the Photonic Crystal example, where a photonic crystal
structure is studied. This structure has a band gap, so only waves within a specificfrequency range will propagate through the outlined guide geometry. This example
changes the position of the pillars in order to maximize the ratio of the transmission at
the desired frequency to the transmission at the undesired frequency.
SINGLE MODE FIBER-TO-FIBER COUPLING

Focusing a laser beam onto the tip of a single-mode fiber is a common way to couple
light. To achieve a good coupling efficiency, the spatial mode of the light field has tomatch the spatial mode of the fiber. In this example, we use the Electromagnetic
Waves, Beam Envelopes interface to compute a small free-space fiber-fiber coupling.
The coupling efficiency depends on the position of the coupling lenses.
UPDATED MODELS

Application Library Path for Model Using the New Gaussian Beam Input Power
Option• Wave_Optics_Module/Nonlinear_Optics/self_focusing

170 |CHAPTER 1: RELEASE NOTESApplication Library Path for Models Using the New Curl Shape Function• Wave_Optics_Module/Beam_Propagation/orbital_angular_momentum

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Material Library
New and Updated Material Data in Version 5.6
In version 5.6, the following improvements have been made:• The following materials are now available: CMSX-4 Plus (SLS); Cu-8Al; Cu-26Cr;
Cu-8Cr-1Al; Cu-17Al-5Al; Cu-23Cr-5Al; P355N; P355NH; P355NL1;
P355NL2; 15-15HS; AerMet 340; CarTech ACUBE 100; Hypocore alloy;
MagneDur 20-4 alloy; H19; CBS-223 VIM-VAR; CarTech No. 1 JR alloy type 1,
2, 4; and Ti - 6 Al - 4 V, Grade 5.
• Stress-strain curves in compression have been added.
• S-N data has been added for 4140, 51SiCr7, 1008, 1020, 1040, 2315, 2330,
4330V, 8630, 8640, HY-TUF, Super HY-TUF, H23, Stellite 31, ZK60, AZ81,
maple, and birch.
• Data has been added for DIROS 500 S, P500QL2, P690Q, A537 (S185), AerMet
100, AF1410, 1008, 1020, 1040, 4135, 4037, 5140, 9310, 1080, 4130, 300M,
and glassy Se.
• More data for molten salts has been added.
• Isochronous creep data and creep data for several aluminum alloys have been added.
• The stress-rupture data for UNS C90500 was incorrect and has been removed.
• The test temperatures for the stress-rupture data for “Inconel 600 - solution
treated” were incorrect and have been corrected.
• The stress-strain and % elongation data for magnesium alloy WE54 were incorrectand have been corrected.
• The data for Inconel C-276 and Hastelloy C-276 were combined, and Hastelloy C276 was removed.
• The reference for the expansion of 2205 steel was changed. The new values are 5%
to 10% higher than the old values.

172 |CHAPTER 1: RELEASE NOTESLiveLink™ for Excel ®
New Functionality in Version 5.6
MODEL PARAMETERS

Direct support for models that have more than one parameter node is added to thetoolbar. This makes it easier to work with models that have a lot of parameters.

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LiveLink™ for MATLAB ®
New Functionality in Version 5.6
LiveLink™ for MATLAB® now supports MATLAB® 2020a and 2020b.
The following sections list new and improved functionality in LiveLink™ for
MATLAB®.
MPHNAVIGATOR

The model.capeopen node has been renamed to model.thermodynamics.
An extra node, model.externalInterface, has been added. It contains any settings
for the Simulink® cosimulation export (which requires the new product LiveLink™ for
Simulink®).
LAUNCHERSCOMSOL with MATLAB and COMSOL with Simulink are sharing the samelaunchers, which set the static Java class path as opposed to setting the dynamic classpath in previous releases. This means that you can only use the mphstart command
when working with LiveLink™ for MATLAB® and not when using LiveLink™ for
Simulink®, which requires a static class path.
MPHSAVE AND MPHLOAD

These functions now support the use of tags of the model on the server instead of themodel variable. This makes it easier to work with multiple models on the server.
You can save a model with the tags Model using this command
mphsave('Model')You can retrieve the model variable for a model on the server using this commandmodel = mphload('Model')MPHPLOTPlots with transparency on some of the plot features are supported. Plot with images
and material appearance are not supported in MATLAB. Themes and clipping are notsupported.

174 |CHAPTER 1: RELEASE NOTESMPHGEOMUsing
h = mphgeom(model, 'geom1')

you get a handle to the plotted objects, which can later be used for customization in
MATLAB.
MATERIAL PARAMETERS

Material parameters from another MPH-file can now be loaded using a single line as
opposed to having code that sets each material property line by line.
MPHINTERPThe new error message “Argument COORD has incorrect orientation or size” makes
it easier to detect when coordinates are of the wrong size (or have been transposed).

Backward Compatibility with Version 5.4
The mphreduction function has been changed in version 5.5 such that it no longer
can be used to define model reduction studies. You have to manually add the necessary
studies to the model. The mphreduction function can then be used to extract thedefined matrices for use in MATLAB.

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The COMSOL API for Use with Java ®
COMSOL 5.6 API Changes
MESH PART UNITSThe unit of the mesh part created by createMeshPart is now set to the unit of thesource geometry. In earlier versions, it was created without a unit.
THE ADAPT FUNCTION — THE EXPRTYPE PROPERTY

For the adapt API function, the default for the exprtype property has changed: It iserror if added in a component and a solution exists; otherwise, it is size. In previous
versions, the default was always error.

COMSOL 5.4 API Changes
CAD IMPORT MODULE, DESIGN MODULE, AND LIVELINK PRODUCTS FORCAD CHANGESThe new fillholes property has been added for the Import function. The following
applies:• The combination of the fillholes property set to on and the knit property set tosolid is equivalent to the knit property set to solid in previous versions.
• The combination of the fillholes property set to off and the knit property set
to surface is equivalent to the knit property set to surface in version 5.3a.
• The combination of the fillholes property set to on and the knit property set tosurface is equivalent to the knit property set to surface in version 5.3 andprevious versions.
The new fillholes property has been added for the Knit function. The Knit
function with the fillholes property set to on corresponds to the Knit function inprevious versions.
ECAD IMPORT MODULE CHANGES• The properties selnetcontributetobnd, selnetcontributetodom,
selnetkeepbnd, selnetkeepdom, selnetnamebnd, selnetnamedom,selnetshowbnd, selnetshowdom, selnettagbnd, and selnettagdom have been
added to the Import function. The properties apply to the IPC-2581 and ODB++176 |CHAPTER 1: RELEASE NOTES

file types and enable working with the selections generated for the electrical nets
found in the imported files.
• The elevation property of the Import function is now initialized when setting themanualelevation property to off. Previously, it was only initialized when setting
the filename property and when the manualelevation property is off and thevalue of either the height or importtype properties is changed.

COMSOL 5.3a API Changes
PARTITION OBJECTS PROPERTIESThe keep property has been deprecated in version 5.3a. Instead, use the newproperties keepinput and keeptool. If you set keep to on, both keepinput andkeeptool are set to on. If you get the value of keep, it is on if keepinput andkeeptool are on.

COMSOL 5.3 API Changes
NEW COMPONENT SYNTAXThe geometry component is now included in the code for features that appear in acomponent. For example,
model.geom("geom1")

in earlier versions is now instead
model.component("comp1").geom("geom1")

to indicate which component the geometry belongs to. To keep the old syntax ingenerated Model Java® files, clear the Use component syntax check box under Codegeneration on the Methods page in the Preferences window. All old scripts and Java®
source code files will continue to work using the old syntax.
ECAD IMPORT MODULE CHANGES• The default value for the sellayer property of the Import function is now on.
Previously, the default was off.
• The default value for the sellayershow property of the Import function is now
all. Previously, the default was dom.

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177COMSOL 5.2a API Changes
AC/DC MODULE CHANGESNew Coil Feature
In the Magnetic Fields, Magnetic and Electric Fields, and Rotating Machinery,
Magnetic interfaces, a new unified Coil feature has replaced the Multi-Turn Coil feature.
The functionality of the old Multi-Turn Coil feature can be replicated by using the new
Coil feature with the Conductor model set to Homogenized Multi-Turn, but all of theother parameters are unchanged. The only change required is to the create statements
such as:model.physics("mf").feature().create("mtcd1","MultiTurnCoilDomain", 3);

which should be modified to:model.physics("mf").feature().create("mtcd1", "Coil", 3);model.physics("mf").feature("mtcd1").set("ConductorModel","Multi");

User-Defined Coil Geometry Subfeature Selection
In 3D models, when using a user-defined geometry for a Coil feature, the User Defined
Coil Geometry subfeature has been transformed from a boundary feature to a domainfeature. New Input and Output subnodes are used to select the coil input or output
boundaries instead. Any code setting the selection of this feature should be modified
to set the selection on the Input subfeature instead.

Relative Permeability for Magnetic Shielding in Magnetic Fields, No Current
The relative permeability parameter mur in the Magnetic Shielding feature in the
Magnetic Fields, No Currents interface is now a scalar quantity. Setting a tensor
quantity will not cause exception, but only the first component of the tensor will be
used as the value.
ACOUSTICS MODULE CHANGESThe default settings have changed for the Incident Pressure Field in the Pressure
Acoustics interfaces. Add the following line to obtain the old behavior of this featurewhen ipf1 is a subfeature to pwr1:
model.physics("acpr").feature("pwr1").feature("ipf1").
set("c", "acpr.c_c");

178 |CHAPTER 1: RELEASE NOTESCOMSOL 5.1 API Changes
ACOUSTICS MODULE CHANGESThe ratio of specific heats is now a material parameter. If the default value was used ina model, add the following line to the Java® file to obtain the old behavior:model.physics("cpf").feature("cpf1").set("gamma_mat", "userdef");
ELECTROCHEMISTRY MODULES CHANGES

There are changes for the Tertiary Current Distribution, Nernst-Planck interface. The
Java® API syntax for creating and accessing vectors and tensors has changed, as well as
the syntax for setting physics properties. See the following examples:• Specifying the diffusion tensor.
Old syntax:
model.physics("tcdee").feature("ice1").set("D_0", newString[]{"D1", "0", "0", "0", "D1", "0", "0", "0", "D1"});model.physics("tcdee").feature("ice1").set("D_1", newString[]{"D2", "0", "0", "0", "D2", "0", "0", "0", "D2"});model.physics("tcdee").feature("ice1").set("D_2", newString[]{"D3", "0", "0", "0", "D3", "0", "0", "0", "D3"});New syntax (includes the species name in the first argument of the set method):model.physics("tcdee").feature("ice1").set("D_c1", newString[]{"D1", "0", "0", "0", "D1", "0", "0", "0", "D1"});model.physics("tcdee").feature("ice1").set("D_c2", newString[]{"D2", "0", "0", "0", "D2", "0", "0", "0", "D2"});model.physics("tcdee").feature("ice1").set("D_c3", newString[]{"D3", "0", "0", "0", "D3", "0", "0", "0", "D3"});• Accessing tensor components (in the definitions of other variables, for example).
Old syntax:
Dxx_c1, Dxy_c1, Dxz_c1...

New syntax (component index after the species name):
D_c1xx, D_c1xy, D_c1xz...

• Specifying the reaction rate vector.
Old syntax:
model.physics("tcdee").feature("reac1").set("R_0", newString[]{"R1"});model.physics("tcdee").feature("reac1").set("R_1", newString[]{"R2"});

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model.physics("tcdee").feature("reac1").set("R_2", newString[]{"R3"});New syntax (includes the species name in the first argument of the set method):model.physics("tcdee").feature("reac1").set("R_c1", newString[]{"R1"});model.physics("tcdee").feature("reac1").set("R_c2", newString[]{"R2"});model.physics("tcdee").feature("reac1").set("R_c3", newString[]{"R3"});• Accessing vector components.
Old syntax:
tfluxx_c1, tfluxy_c1, tfluxz_c1

New syntax (component index after the species name):
tflux_c1x, tflux_c1y, tflux_c1z• Specifying initial values.
Old syntax:
model.physics("tcdee").feature("init1").setIndex("c2", "c20", 0);model.physics("tcdee").feature("init1").setIndex("c3", "c30", 0);model.physics("tcdee").feature("init1").setIndex("V", "V0", 0);

New syntax:
model.physics("tcdee").feature("init1").setIndex("initc", "c20",
1);model.physics("tcdee").feature("init1").setIndex("initc", "c30",
2);model.physics("tcdee").feature("init1").setIndex("initphil","V0");• Selecting properties.
Old syntax:
model.physics("tcdee").prop("Convection").set("Convection", 1,"0");model.physics("tcdee").prop("ConvectiveTerm").setIndex("Convectiv
eTerm", "noncons", 0);

New syntax (the property name corresponds to the section in the user interface):model.physics("tcdee").prop("TransportMechanism").
set("Convection", 1, "0");model.physics("tcdee").prop("AdvancedSettings").setIndex("Convect
iveTerm", "noncons", 0);180 |CHAPTER 1: RELEASE NOTESFor information about API backward compatibility for the Surface Reactions interface,see the Chemical Reaction Engineering Module release notes.
ECAD IMPORT MODULE CHANGES• The default value for the grouping property of the Import function is now set tolayer. Previously, the default was all.
• For ODB++® and ODB++(X) files (the type property is odb), new rules apply forthe initialization of the importlayer property of the Import function. Now, only
layers of the types Metal and Dielectric are initialized with the string on in theimportlayer string array. Previously this also included layers of type Drill.
LIVELINK™ FOR SOLID EDGE® CHANGESThe default value for the keepfree property of the LiveLinkSolidEdge function is
now set to on. Previously, the default was set to off.
LIVELINK™ FOR SOLIDWORKS® CHANGESThe default value for the keepfree property of the LiveLinkSOLIDWORKS function is
now set to on. Previously, the default was set to off.

COMSOL 5.0 API Changes
DOCUMENTATIONThe COMSOL Multiphysics Programming Reference Manual replaces the
COMSOL API for Use with Java ® Reference Manual.
DEPRECATED METHODS

The following methods were deprecated in COMSOL 5.0:
TABLE 1-1: DEPRECATED METHODS AND THEIR REPLACEMENTS
DEPRECATED METHODNEW METHOD

com.comsol.model.OptFeature.field()

OptFeature.comp()

com.comsol.model.OptFeature.field(String)

OptFeature.comp(String)com.comsol.model.Group.identifier()

Group.paramName()com.comsol.model.Material.identifier()

ModelEntity.tag()com.comsol.model.MaterialModel.
identifier()

ModelEntity.tag()com.comsol.model.ModelNode.identifier()

ModelEntity.tag()

THE COMSOL API FOR USE WITH JAVA®

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181

TABLE 1-1: DEPRECATED METHODS AND THEIR REPLACEMENTS

182 |DEPRECATED METHODNEW METHOD

com.comsol.model.physics.Physics.
identifier()

Use tag() instead.

com.comsol.model.physics.
MultiphysicsCoupling.identifier()

ModelEntity.tag()com.comsol.model.Group.identifier(String)Group.paramName(String)com.comsol.model.Material.
identifier(String)

ModelEntity.tag(String)com.comsol.model.MaterialModel.
identifier(String)

ModelEntity.tag(String)com.comsol.model.ModelNode.
identifier(String)

ModelEntity.tag(String)com.comsol.model.physics.Physics.
identifier(String)

Use tag(string) instead.

com.comsol.model.physics.
MultiphysicsCoupling.identifier(String)

ModelEntity.tag(String)com.comsol.model.ModelEntity.name()

ModelEntity.label()com.comsol.model.ModelEntity.name(String)

ModelEntity.
label(String)com.comsol.model.ParameterEntity.
set(String, int, double)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, double)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, double[])Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, int)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, int[])

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, int, double)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, int, int)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, int, String)

Use the 0-based version(setIndex) instead.

CHAPTER 1: RELEASE NOTESTABLE 1-1: DEPRECATED METHODS AND THEIR REPLACEMENTS
DEPRECATED METHODNEW METHOD

com.comsol.model.ParameterEntity.
set(String, int, String)

Use the 0-based version(setIndex) instead.

com.comsol.model.ParameterEntity.
set(String, int, String[]

Use the 0-based version(setIndex) instead.

This concludes the release notes for COMSOL Multiphysics version 5.6.

THE COMSOL API FOR USE WITH JAVA®

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183

184 |

CHAPTER 1: RELEASE NOTESI n d e x
A

AC/DC ModuleD

new and updated models in 37
new functionality in 36

new functionality in 52
E

Acoustics Module

new functionality in 79

Application Builder, new functionality inElectrodeposition Module

10

backward compatibility 87

backward compatibility, general consid-

new and updated models in 86

erations 31
Battery & Fuel Cells Module

Electrochemistry Module
backward compatibility 82

backward compatibility 46

B

Design Module

new functionality in 83
Fbackward compatibility 51

Fatigue Module
new functionality in 88

new and updated models 51
new functionality in 47

G

general new functionality 10
Geomechanics ModuleC

CAD Import Module

new functionality in 89

new functionality in 52

new models in 90

CFD Module

geometry and mesh, new functionality

backward compatibility 59

for 17new functionality in 56
new models in 57

H

backward compatibility 97–99, 101, 111

Chemical Reaction Engineering Module

new applications in 96

backward compatibility 58, 66–67

new functionality in 91

new applications in 64
new functionality in 60

Heat Transfer Module

L

Composite Materials Module

LiveLink for Excel
new functionality in 173

new functionality in 68

LiveLink for MATLABCOMSOL API changes 176

backward compatibility 175

COMSOL Compiler

new functionality in 173–174

new functionality in 13

LiveLink™ products for CAD

COMSOL Multiphysics, new functionality in 14
COMSOL Server, new functionality in 14
Corrosion Module
backward compatibility 77
new and updated models in 76
new functionality 73

new functionality in 52
M

Material Library
new and updated material data in 172
new material data in 172
MEMS Module
new functionality in 103
Metal Processing Module

I N D E X | 185

new functionality in 109

new functionality in 144

Microfluidics Module

new functionality in 147

new functionality in 111

new models in 149

new models in 110
Mixer Module
new functionality in 113
Multibody Dynamics Module
new functionality in 114
N

Nonlinear Structural Materials Module
new functionality in 120
new models in 122

O

operators, functions, and definitions,
new and updated 20
Optimization Module
new functionality in 124

P

Particle Tracing Module
backward compatibility 130
new applications in 130
new functionality in 127
Pipe Flow Module
new functionality in 132
Plasma Module
backward compatibility 133
new functionality in 133
Porous Media Flow Module
new functionality in 134
new models in 137

R

Ray Optics Module
backward compatibility 141
new applications in 140
new functionality in 138
results and visualization, new functionality in 25
RF Module
new and updated apps and models in
145

186 | I N D E X

Rotordynamics Module

backward compatibility 112

S

Semiconductor Module
new applications in 152
new functionality in 151
Structural Mechanics Module
new functionality in 154
new models in 162
studies and solvers, new functionality in
22

Subsurface Flow Module
new functionality in 165
new models in 166
W Wave Optics Module

new functionality in 168
new models in 169