bluuebunny/crossref_metadata_2025 huggingface dataset:
Device Prototype for Vaginal Delivery of Extremely Preterm Fetuses in the Breech Presentation
Authors: Whalen Mallory , Chang-Davidson Elizabeth , Moran Terra , Hoffman Rachel , Frydman Galit H. , Slocum Alexander , Dangel Alissa
Published: November 2020

Vaginal delivery is typically avoided in the extremely preterm breech population due to the concern of entrapment by the cervix of the aftercoming head. A mechanical device concept is presented to enable vaginal delivery by preventing retraction of the cervix against the fetus during delivery. The two-part device was designed to dilate the cervix, prevent prolapse of small fetal parts and maintain sufficient dilation during delivery. The two-part device was designed and manufactured with the following modules: an inflatable saline-filled cervical balloon for dilation and a cervical retractor composed of semirigid beams to stabilize the cervix and maintain adequate dilation. The device was tested using a cervical phantom designed to simulate the compressive force the cervix exerts. The cervical balloon reached a maximum dilation of 8.5 cm, after which there was leakage of saline from the balloon. While this dilation was less than the target goal of 10 cm, the leaking was attributed to prototype manufacturing defects, which could be resolved with further development. The cervical retractor was able to withstand between 1–3 kPa. Although estimates of cervical pressure values can be upward of 30 kPa, there are no in vivo measurements to formally identify the pressure values for patients in preterm labor. This device serves as a viable proof-of-concept for utilizing an inflatable balloon device to prevent cervical retraction in the setting of extremely preterm vaginal breech delivery. Further manufacturing improvements and design changes could improve the device for continued development and testing.
Effect of Sequential Helium and Nickel Ion Implantation on the Nano-Indentation Hardness of X750 Alloy
Authors: Tawfeeq Maisaa N. , Klassen Robert J.
Published: November 2020

Sequential He+ and Ni+ implantations were performed to investigate their combined effect on the indentation hardness of heat-treated X750 alloy. The microstructure of the ion-implanted region was also characterized with transmission electron microscope (TEM). The X750 alloy displayed a pronounced softening with very low Ni+ implantation levels, ψ = 0.01–1.0 dpa, however it showed a clear increase in hardness when implanted with He+ up to CHe = 5000 appm. Samples subjected to sequential He+ and Ni+ implantations displayed hardness values between those presented by sole He+ or Ni+ implantation suggesting that the effects of ion-induced microstructural damage and helium accumulation on the hardness of this alloy can be considered as independent and additive over the range of conditions studied. This observation is in contradiction to previously reported TEM-based studies, which suggest that accumulated helium slows the dissolution/disordering of the γ′ hardening phase in this alloy. In our study, established theories were applied to assess the contribution of ion-induced defect clustering, γ′ precipitate disordering, and helium bubble accumulation to the hardness of the X750 alloy. It was observed that generation of ion-induced defect clusters and the formation of helium bubbles increased the indentation hardness slightly while the disordering of γ′ precipitates resulted in a dramatic decrease in the total hardness. Ni+ and He+ implantation also had different effects on the depth dependence of the indentation hardness indentation size effect (ISE). The ISE was pronounced in the samples subjected to only Ni+ implantation while it was almost absent in samples subjected to only He+ implantation.
Experimental and Numerical Investigation of Solidification of Gallium in an Initially Emptied Horizontal Pipe Flow
Authors: Somers-Neal Shawn , Pegarkov Alex , Matida Edgar , Tang Vinh , Kaya Tarik
Published: November 2020

In a reactor core meltdown under postulated severe accidents, the molten material (corium) could be ejected or relocated through existing vessel penetrations (cooling pipe connections), thus potentially contaminating other locations in the power plant. There exists, however, a potential for plugging of melt flow due to its complete solidification, providing the availability of an adequate heat sink. Therefore, a numerical model was created to simulate the flow of molten metal through an initially empty horizontal pipe. The numerical model was verified using a previously developed analytical model and validated against experimental tests with gallium (low melting temperature) as a substitute for corium. The numerical model was able to predict the penetration length (length of distance traveled by the molten metal) after a complete blockage occurred with an average percent error range of 9%. Since the numerical model has been verified and validated, the model was updated to predict the penetration length in the cooling pipe in case of a severe accident. The model was used to predict the penetration length for different Reynolds numbers and pipe diameters, which resulted in the range of penetration length from about 0.33 m to 0.93 m.
Container Spaces and Functional Features for Top-Down 3D Layout Design
Authors: Csabai A. , Xirouchakis P.
Published: November 2020

During the conceptual phase of product design, rapid generation of the rough assembly description and capture of the product layout should be supported. This work introduces a top-down approach for creating the product layout and facilitating subsequent detailed design. For this purpose design spaces are introduced. These design spaces represent the conceptual boundary of the components as well as references for defining relationships between the functional parts of the assembly. These functional units can be connected together by means of interface features and constraints. Once the design spaces and the relationships have been set up correctly the task of refining the components geometrically can be distributed and done in parallel. This concurrent work is controlled with access rights and well-defined responsibility areas. Since the layout and the component level are strictly delimited, kinematic analysis as well as layout modifications can be done at any stage of the product design without any explicit information about the geometry of the components. The presented top-down method, called 3D Layout Modeller (3DLM), facilitates capturing the human intention of the constructional design by providing tools and methods for doing this in a natural manner. This means that the design process starts with the overall definition of the functional behaviour of the product and the detailed description of the components remains for the design refinement stages (“minimum commitment modelling”). Since there must be well defined connections between the components, the project can be separated into different tasks. It is possible that a task can also be further divided, which indicates the hierarchical nature of the method.
A Concept for the Support of an Efficient Search for Product Data
Authors: Ahrens Gritt , Düsselmann Sven
Published: November 2020

An effective data management is fundamentally important in product development due to the high level of interrelations between the departments, the high variety of the type of documents generated in order to document the development steps and the high rate of searching processes in development activities. In the following paper a graphical means is defined and used to illustrate the data saved during product development/design and its interrelations. This means, which is based upon investigations on design methodology as well as work science, is then used as the backbone of the presented IT-concept for a descriptive support of searching processes. Furthermore, the universality and flexibility of the tool ELEIT is demonstrated when the integration of an add-on tool, named SPECtool, that focuses on the collection and management of requirements is demonstrated.
Pattern-Based Approach in Conflict Cause Identification in Distributed Design Environment
Authors: Jiang Tianhong , Nevill Gale E.
Published: November 2020

In this paper, a well-organized structure of conflict classes and causes is presented. Based on our study of nature of the conflicts and the associated value patterns in design, a pattern-based computational model is proposed for conflict cause identification and successfully tested in Plane World distributed design simulation.
Dynamic Configuration Evolution of Distributed CE Design in Object-Oriented Databases
Authors: Al-Khudair A. , Gray W. A. , Miles J. C.
Published: November 2020

This paper discusses the evolution of the configurations of a complex design artifact in a distributed concurrent engineering (CE) design environment. A generalized object-oriented model which captures the evolution of configurations and their components will be preseneted. We not only describe the object-oriented model, we also show how the dynamics between a configuration version and its components’ versions is maintained. The notions of version domain and version provenance are introduced to represent the domain-specific versions and to show how an object version arrives in its current state based on the 5W provenances (When, Who, Where, What and Why). A distributed architecture of a CE design environment will be also presented.
Disassembly Aimed at Product Remanufacturing
Authors: Lambert A. J. D.
Published: November 2020

This paper describes a new approach for lot size optimisation for multiple product configurations to meet the demand on the different components that are present in it. Commonality and multiplicity are dealt with. The method is placed within the framework of general disassembly sequence planning with an emphasis on the minimisation and further processing of the required amount of product data. A case has been worked out for demonstrating the method. Some recommendations for further extension of the method are given.
Multi-User Modeling of NURBS-Based Objects
Authors: Foster Cheryl V. , Shapirstein Yuri , Cera Christopher D. , Regli William C.
Published: November 2020

This paper presents MUG, a multi-user environment for collaborative conceptual shape design. The majority of current research prototypes and commercial systems for collaborative modeling emphasize data sharing and markup. Collaborative 3D environments and virtual worlds usually restrict themselves to models with display representations (e.g., VRML) and asynchronous sharing of distinct objects. Our MUG prototype enables collaborative modeling of individual shapes: multiple users, operating at a distance, working on the same design. In our current work, we have focused on collaborative shape modeling of NURBS — allowing users to select control points and concurrently manipulate the same entity.

To achieve this functionality, we have developed a protocol for synchronous mathematical construction of NURBS forms. We have adopted a multi-client/single server architecture in which changes are synchronized at a collaboration server and propagated to the clients. Our implementation uses Sun Microsystems’ Java, along with the Java3D and JavaSpaces extensions. In addition, as part of this work, we have developed a Java-based NURBS library, as well as faceting and rendering routines specifically suited for a light-weight collaborative environment.

We believe that as network connectivity continues to radically reshape the design process, we need to enable new design techniques based on intimately shared design spaces. We believe that our approach illustrates one channel in which collaborative engineering systems can be better integrated with collaborative work environments.
Designing Flexible Production Systems With Virtual Reality
Authors: Gausemeier Jürgen , Krumm Holger , Grafe Michael , Ebbesmeyer Peter
Published: November 2020

This paper provides an overview of the possibilities for using virtual reality technology in engineering applications. It concentrates on the planning and design of manufacturing processes and plants as well as facility planning. Modern design tools like simulation technology are introduced and it is discussed how these tools can be used in combination with virtual reality. Selected sample cases describe the benefits of using these technologies.
Design Synthesis in a Virtual Environment
Authors: Maxwell Douglas , King Rob , Butler Alley
Published: November 2020

Traditional computer-aided design/engineering (CAD/CAE) is performed in a two-dimensional (2D) environment. Through the CAD system demonstration described in this paper, an alternative to the existing 2D technology for design of products is described. This alternative in which design synthesis is accomplished in a stereoscopic or immersive environment is called the Design Synthesis Virtual Environment or DSVE. Stereoscopic vision permits depth perception and provides perception of “real world” 3D existence. This DSVE technology, as defined in this paper, provides a virtual or immersive environment, computer-generated, but seemingly real.

The authors argue that significant advantages are possible when an immersive environment such as the DSVE is used for design synthesis. In the Design Synthesis Virtual Environment a gestural interface is used, and it is further argued that designers can perform design activities intuitively by using a more natural gestural interface within the design environment, allowing more rapid, efficient actions to create and/or modify product geometry.

As evidence, this paper reports on a demonstration conducted in a Design Synthesis Virtual Environment. Operation of the DSVE is explained, and two example problems are worked. Conclusions are drawn about the effectiveness of the DSVE and the potential for further development.
A New Method for Building B-Spline Curves and its Application to Geometry Design and Structured Grid Generation
Authors: Flórez Guzmán Horacio
Published: November 2020

A new approach for building two-dimensional B-spline curves and its application to Computer-Aided Geometry Design is presented. The method constructs smooth curves based on a new knot sequence with an iterative refinement procedure suitable for the design of complex geometries. This knot sequence is applied to quadratic and cubic spline curves in two cases of interest, namely inverse design and interpolation problems. For the latter the linear system of equations is given, taking into account the appropriate end conditions. Several figures and examples from Computational Fluid Dynamics have been included to compare the proposed scheme with others. The results show that the method is a powerful and robust tool in curve design. Finally, an algorithm for solving the problem of interpolation along a B-spline curve is proposed and its potential application to 2-D structured grid generation is discussed.
Generalizing of Numerically Solving Methods of Eigenvalue Problems to Asymmetrical, Damping Included Case
Authors: Rezaei Shahram
Published: November 2020

In this paper, “Subspace” method is generalized to asymmetrical case. In the new algorithm described here, “Lanczos” method is used to find the first subspace and to solve the eigenvalue problem resulted in generalized subspace method. To solve the standard eigenvalue problem developed by “Lanczos” method “Jacoby” method is used. If eigenvalue problem includes damping matrix, that will be imported in new defined mass and stiffness matrices.
Control of Conical Shells Laminated With Full and Diagonal Actuators
Authors: Tzou H. S. , Wang D. W. , Chai W. K.
Published: November 2020

Nozzles, rocket fairings and many engineering structures/components are often made of conical shells. This report focuses on the finite element modeling, analysis, and control of conical shells laminated with distributed actuators. Electromechanical constitutive equations and governing equations of a generic piezo(electric)elastic continuum are defined first, followed by strain-displacement relations and electric field-potential relations of laminated shell composites. Finite element formulation of a piezoelastic shell element with non-constant Lamé parameters is briefly reviewed; element and system matrix equations of the piezoelastic shell sensor/actuator/structure laminate are derived. The system equation reveals the coupling of mechanical and electric fields, in which the electric force vector is often used in distributed control of shells. Finite element eigenvalue solutions of conical shells are compared with published numerical results first. Distributed control of the conical shell laminated with piezoelectric shell actuators is investigated and control effects of three actuator configurations are evaluated.
Prediction of Thermal Displacements in Finite Element Tool Models
Authors: Aßmus Jörg , Wessel Niels , Kurths Jürgen , Weidermann Frank , Konvicka Jan , Nestmann Steffen , Neugebauer Raimund
Published: November 2020

Precision and productivity are very important criteria for the evaluation of modular tool systems and require a thermally stable process with tolerances in the micrometer range. During the past decades there has been an increasing interest in compensating thermally induced errors. In this paper we investigate wheather a prediction of thermal displacement based on a nonlinear regression analysis is possible, namely using the alternating conditional expectation algorithm (ACE) introduced by Breiman and Friedman, 1985. The data we are analyzing were generated by two different finite element spindle models of modular tool systems. As the main result we find that the ACE-algorithm is a powerful tool to model the relation between temperatures and displacements. It could also be a promising approach to handle well-known hysteresis effects. Limitations of this study are the model restricted results, next our findings have to be validated on real data.
Response of Submerged Structures by the Finite Element-Cum-Boundary Element Method
Authors: To C. W. S. , O’Grady M. A.
Published: November 2020

A double asymptotic approximation based finite element-cum-boundary element approach for fluid-structure interaction problems is being proposed. In particular a staggered solution scheme has been applied to the analysis of various coupled fluid-structure systems. A stabilization scheme by reformulation, proposed by DeRuntz et al. was employed to circumvent the instability problem. In addition, the singularity in the excitation term was eliminated through a variable transformation as suggested by Everstine. Another feature of the present work is its incorporation of the hybrid strain based lower order triangular shell finite element developed by To and Liu. The eigenvalue solution exhibits high convergence rate for the particular shell finite element employed. The responses calculated exhibit the effectiveness of the proposed approach with application of the aforementioned shell finite element in dealing with three dimensional fluid-structure interaction problems. The reduction in problem size that this approach affords allows these complex interaction problems to be dealt with in a desktop engineering workstation environment, as opposed to the mainframe and supercomputer arenas where they have been implemented in the past.
Design and Utilization of an Impact Pendulum for Assessing Energy Losses due to the Impact of a Projectile With an Arbitrary Medium
Authors: Khosrowjerdi Mohammad , Aflaki James
Published: November 2020

A ballistic or compound pendulum is used either to determine the velocity of a projectile or as a laboratory tool to teach impact momentum and principle of work and energy. It also lends itself well to the study of energy losses caused by the inelastic impact of a projectile with a medium. One useful application of the latter use of these pendulums is in the investigation of the effects of medium characteristics on the energy loss and the design of more effective lethal weapons.

A compound pendulum has been designed, instrumented and used to measure the energy losses during the plastic impact of a projectile with an arbitrary medium. The energy loss is calculated from the projectile velocity just before impact and the pendulum angular velocity immediately after impact or the pendulum maximum angular displacement. The angular displacement and velocity measurements are performed by a precision potentiometer and a PC-based data acquisition system in an automated manner to enable collection of extensive data in a reasonable period of time. The PC-based data acquisition used in this study is an in-house developed one that is capable of handling and storing massive amount of data and providing the ability to perform statistical and other computational analyses.

This paper discusses the procedure for designing the impact pendulum, in particular the selection of proper transducers and the data acquisitions system, and gives an overview of the software that has been developed to fully automate the energy loss calculation.
Windows-Based Portable Laboratory System for Demonstrating Heat Transfer From an Extended Surface
Authors: Khosrowjerdi Mohammad , Dini Said , Aflaki James
Published: November 2020

An Armfield™ small bench top service unit (HT10X) in conjunction with an extended surface heat transfer assembly (HT15) are utilized to demonstrate the temperature profile and heat transfer characteristics of a cylindrical rod. Heat flows along the rod by conduction and is lost to the surroundings by combined natural convection and radiation. This well-instrumented laboratory teaching equipment allows students to measure the temperature distribution along the rod and compare the result with a theoretical analysis. Also, heat transfer from the extended surface resulting from the combined modes of free convection and radiation heat transfer is investigated.

A self-contained Windows-based data collection and analysis system has been developed for automating all the manual functions of the Armfield™ extended surface heat transfer assembly; HT15. This system uses an inexpensive plug-in data acquisition board to read the voltage signals corresponding to nine K-type thermocouples and heater supplied voltage and current. The user interface software that is written in Visual Basic 6 uses 32-bit libraries to control the heater voltage and read the thermocouples voltages and heater supplied voltage and current. Used in conjunction with the HT15 unit, the software is a valuable teaching tool for instructors and provides a comprehensive learning environment within which heat transfer characteristics can be studied. It is aimed at enhancing the students understanding of one dimensional heat conduction along a cylindrical rod and enabling them to contrast theory and practical measurements of temperatures.

It is also the intent of this paper to discuss the successful integration of this educational system into portable instructional technology for the classroom and the mechanical engineering laboratory courses.
A Graph Grammar Based Approach for Development of an Internet-Based Product Family Information System
Authors: Siddique Zahed , Shao Zili
Published: November 2020

Companies are striving to deliver greater quality, more customization, faster response, more innovative designs and lower prices. The new shift in the current market has introduced the concept of product family design using a platform approach. To provide a family of products require establishment of an information framework that can support product and process data exchange among different entities (design, manufacturing, etc.) of the enterprise. Information such as: function, product, process, cost, etc., need to be readily available to ensure proper execution of a product family framework. In this paper, the focus is on generation and management of information among different segments of product development process. The paper presents, development of an information system, such that user customization information for the product, sent over the Internet, is utilized to generate function, assembly and product architecture information for the specified customer product. The information is provided to the customer and the manufacturer to facilitate making decisions regarding the product and associated process.
Distributed Multibody Dynamic Analysis Within Product Development
Authors: Larsson Tobias , Larsson Andreas , Karlsson Lennart
Published: November 2020

A method that supports distribution of multibody dynamic analysis is proposed and developed. Ethnographic methods are used as a means for gaining a deeper understanding of the engineering analysis work practice, and the findings form the base for a cooperative design of the system. The concept of design rationale is applied in order to deal with current problems of engineering analysis, such as irrelevant input and output, as well as satisfying the need for useful, real-time feedback. The web based simulation environment, applied to vehicle system dynamics, contains the simulation packages ADAMS and MATLAB and incorporates database technology. The possibility to distribute simulation models and results, from simulation experts to design experts and engineers, as well as subcontractors, is created. The proposed method requires changes in the existing multibody dynamic simulation methodology regarding aspects of incorporation in product development theories.
Net Informational and Computational System for CFD Researchers
Authors: Goriatchev Valeri , Balachov Mikhail , Rykov Dmitri
Published: November 2020

This paper presents results of developing the Informational and Computational System for CFD Researchers. It is the second generation of SELIGER: System of Embedded-Linked Information and Graphics for Engineers and Researchers. The main goal of the system is a support of CFD and related sciences working in the net environment. Modification of the network prototype is connected with server’s database modernization to provide stable working and fast accessing to server. Java-based applets provide an effective front-end interface to the remote CFD solvers. The network programs support an on-line analysis of complex distributed data set via Internet and are used to derive latent relations between depended values after simulation.
Towards a Specification for a Product Model to Assist the Design of Injection Moulds
Authors: Morano Héctor , Borja Vicente , López Marcelo , Ayala Álvaro
Published: November 2020

Product models come from the analysis of the data requirements to support the design and manufacture of products. These models are implemented in databases aimed at providing information to software applications that assist the concurrent design of products.

This paper presents the requirements of a data model driven software system to aid the design of injection moulds and analyses two product models which were developed in different contexts but capable of representing injection moulded parts and moulds. A case study is used to show the application of each one of the models selected. Finally, some conclusions of the analysis are drawn in order to set the foundation of a new model.
Web-Based Distributed System and Database Modeling for Concurrent Design
Authors: Xue D. , Xu Y.
Published: November 2020

This research introduces a new approach for web-based collaborative concurrent design. In this approach, systems, product libraries, and product databases for modeling different product development life-cycle aspects are distributed at different locations that are linked through the web. Product modeling libraries and databases are described by class features and instance features. Product modeling systems are used for manipulating design activities. A class feature at a remote location can be used for defining a new class feature at the local site. A system at one location can be implemented using the systems at other locations as the components. Distributed life-cycle databases are associated by their relations.
A Survey of Methods and Approaches to Knowledge Management in the Product Development Environment
Authors: Benson Maria , Terpenny Janis
Published: November 2020

Various approaches to capturing and retrieving engineering design information and intent are currently used in industry and play an important role in engineering design collaboration and concurrent engineering. At one end of the spectrum there are expert systems that perform complex analyses of designs based on information that is very specific and specialized for a particular product. At the other end are less automated and less complex non-expert systems. These systems provide the means to organize, collect, and reuse general collections of design intent and rationale in terms of notes, solutions to problems previously encountered, and best practices organized into a database or posted on an internal web site. By surveying the current state of engineering design knowledge management (KM) tools and implementation, conclusions can be drawn regarding the basic elements of successful knowledge management and the opportunities that exist to expand the capabilities and use of such systems in the product development environment. This is of particular relevance to current design practices that are becoming increasingly automated, decentralized, and global. Knowledge management on a large scale will require strategic planning and a deeper understanding to provide the standards for interoperability and exchange that will be needed. This paper provides an overview of approaches to knowledge management in the product development environment.
Representing the Charters of Freedom Encasements in a Design Repository: A Case Study
Authors: Allen R. H. , Fijol R. J. , Szykman S. , Sriram R. D.
Published: November 2020

We report on a case study representing, in an evolving design repository, the design essence of new encasements for the United States Charters of Freedom (CoF) — namely the Constitution, the Declaration of Independence and the Bill of Rights. Specifically redesigned for the purpose of housing and preserving our national documents, the nine encasements each consist of three principal systems — a sealing system, a placement system and a safeguarding system. The encasements were needed to replace the ones manufactured in the early 1950s, because of glass deterioration; these newer encasements are designed to last 100 years. To populate the design repository, we represent engineering geometry, function and associated behavior. We model geometry with digital photographs and Virtual Reality Markup Language (VRML) models of actual Computer-Aided Design (CAD) drawings, and represent function with linked textual descriptions. Design rationale is represented explicitly. Through an evolving user interface, this representation serves to capture the more than 50 parts and systems of the encasements in such a way that the information relating to form, function, behavior and rationale is accessible and browsable to interested parties via the Internet. We conclude that such a representation, or ones similar to it, can provide the basis for a generic design repository, in which specific information — including design rationale — can be readily accessed by interested parties.
Tool Path Planning Algorithm of Normal Curvature Approach Milling Model for Freeform Surfaces
Authors: Yi Xianzhong
Published: November 2020

The normal curvature approach model is a new milling method of machining complex freeform surfaces presented in this paper based on 5-axis CNC machines. For this milling model, its key is to optimize the CL-data of whirlwind milling tool so that the symmetric rotational surface, which is generated while the whirlwind milling tool rotates, can closely approach to the surface being machined. Then, this method evidently raises the material removal rate at the point of contact and efficiently improves the machining productivity.

In the paper, a new-typed whirlwind milling tool with standard-sized circular cutters is introduced, and a special 5-axis CNC horizontal bed-typed milling machine is used in manufacturing the freeform surfaces. The tool path generation algorithm about normal curvature approach milling method and its typical examples are analyzed in detail.
An Effective Geometric and Kinematical Analysis of Ruled Surface Feature Manufacturability for Rapid Prototyping
Authors: de Jager P. J. , Broek J. J. , Horváth I. , Kooijman A. , de Smit A.
Published: November 2020

For rapid prototyping of large objects a method has been developed using an approximation of the shape of the original model with a set of layers with ruled front surfaces. This paper addresses the manufacturability of these ruled surfaces taking into consideration the constraints set by the cutting process (foam material and a heated blade), the kinematics of the equipment and the resulting required velocities and accelerations of the rotation axes. A simple but effective table-based inverse kinematics approach is introduced that enables to search for a set of consecutive orientations while minimizing a user-defined criterion function. The algorithms used are presented and examples of the application are shown.
An Efficient Geometric Algorithm for Extracting Mechanical Components: A Step Towards Developing an Automated Extraction Tool for MEMS
Authors: Bellam Sashidhar , Gupta Satyandra K.
Published: November 2020

Micro-Electro-Mechanical Systems (MEMS) are very small multi-domain devices and systems that contain both mechanical and electrical components with sizes in the order of microns. Design cycle time plays a critical role in the development and introduction of MEMS devices and systems in the market. VLSI designers often use extraction tools to compare the desired schematic with the reconstructed schematic extracted from the spatial layout of the design. Use of such tools in VLSI industry has significantly reduced the number of design iterations. In order to develop extraction tools for MEMS designs, we need geometric algorithms to analyze the spatial layout of the mechanical portion of the MEMS device and extract a net-list of mechanical components. Such extracted net-list of mechanical components can be combined with the electronic component net-list to provide the complete device schematic. A key step in the extraction of mechanical components is classification of various portions of the layout into various types of structural components. Because MEMS designs consist of a large number of components, computational efficiency of the underlying extraction algorithm is very important for it to work on complex devices. This paper describes an efficient geometric algorithm for extracting mechanical components from spatial layout of MEMS designs.
Sketch Based Mesh Extrusion With Remeshing Techniques
Authors: Wang Charlie C. L. , Yuen Matthew M. F.
Published: November 2020

In this paper, we proposed a useful 3D mesh extrusion method for intuitive, efficient geometric modeling of free-form polygonal models. With our method, the user can sketch two strokes to extrude a polygonal mesh surface. Two remeshing techniques: partial mesh re-triangulation and mesh optimization are described in this paper first. After that, the extrusion algorithm with the remeshing techniques is introduced in detail. The method can be widely used in the modeling of free-form polygonal objects. And at the end of this paper, several examples are given.
Defining a Flexible Modeling Methodology for Design and Development of Automotive Powertrain Systems
Authors: Jennings Mark , Tiller Michael , Butts Kenneth R.
Published: November 2020

In this paper we propose, through the use of modeling guidelines and architectures, a modeling methodology that facilitates model reuse throughout the automotive powertrain development process. The goal is to make efficient and timely use of engineering information that is generated during that process, especially in the powertrain design stage. Within this context, we present a modular model architecture and discuss four model-methodology user scenarios (Energy Usage/Management, Design Analysis, Controller Development, and Desktop Calibration). New model applications to support these user scenarios are introduced.
Computer-Generated Virtual/Physical Reality: Blurring the Lines
Authors: Petersen Harry C. , Markowski Andrzej , Sullivan Paul , Petersen Robert
Published: November 2020

As computers grow in ability to access and process ever-larger blocks of data within real-time responses, their ability to generate virtual reality responses has multiplied exponentially. Simultaneously, computer capabilities of using huge data files to control manufacturing processes, create rapid prototypes, augment human senses, and control vehicles and machines have given them the ability to control and even create physical reality. But computers now have the ability to blur the lines between virtual and physical realities in areas which include video manipulation, virtual reality with tactile feedback, and physical training devices such as flight training simulators.

This paper investigates types of computer-generated virtual/physical realities and their uses and implications for industry and consumers alike. Examples of research by the authors in video manipulation and training, solid modeling, animated simulation, manufacturing, rapid prototyping, and reverse engineering will be presented, along with data base corruption, and data manipulation methods and problems. Finally, applications and future implications of this technology will be presented.
An Ant Algorithm Approach to the Isomorphism Identification of Mechanism Kinematic Chains
Authors: Xiao Renbin , He Jinghua , Chang Ming , Shi Hanmin
Published: November 2020

In view of the deficiency in the Isomorphism identification of Mechanism Kinematic Chains (IMKC), we introduce the definition of structure code and covert the problem of IMKC to that of the computation of adjacent matrix’s structural codes for mechanisms. Through some analysis, the conclusion is reached that it is similar to the Traveling Salesman Problem (TSP), a classical combinatorial optimization problem. The converted problem is solved by using an ant algorithm model that can cope with combinatorial explosion and achieve satisfactory results, which is developed recently. In the paper, the principle of ant algorithms is introduced and the implementation of an ant algorithm model for IMKC is given based on the problem conversion. By a practical example of IMKC, the influence of some parameters in the model on the computation results is analyzed in detail and the final result indicates the validity of ant algorithm for IMKC. Thus a new way for the researches of IMKC is presented.
Temperature and Smoke Prediction in Structural Fires
Authors: Kim Hyeong-Jin , Lilley David G.
Published: November 2020

Temperature and smoke level predictions in several rooms of a structural fire are possible with a variety of available computer codes. The accuracy and applicability of the results is greatly enhanced though the comparison of the calculations with experimental data. Experimental work assists in understanding fire behavior in structural fires. Temperature measurements at different locations during a house fire provide necessary data for the development of mathematical models, which attempt to simulate the fire on a computer. In this paper, a small 46 square meter single-level house was the subject of a complete experimental burn, with temperature measurements and fire observations during the entire burn. The CFAST computer code (Consolidated Model of Fire Growth and Smoke Transport) can be used to calculate temperatures and smoke levels in the various rooms of the house during the burn. Five fire scenarios are considered in the simulation, with progressively increasing realism regarding the actual fire specification. It is seen that calculations with the most realistic fire simulation (permitting burning in all rooms during the course of the fire) are in very good agreement with the experimental data, with regard to rate of fire spread throughout the structure, and the accuracy of the calculations of flashover, temperatures and smoke levels in each of the rooms.
Preliminary Design of Wind Turbine Blades for Manufacture Using Local Capabilities
Authors: Al-Zubaidy Sarim N. , Bridge Jacqueline , Johnson Alwyn
Published: November 2020

In the past ten to fifteen years wind energy remerged on the world scene with a very healthy growth rate, it has outstripped photovoltaics (solar cells) as the world’s fastest growing energy source, with a growth rate in excess of 30 percent per annum. No longer just a “nice idea for the future” Wind energy is becoming a mainstream energy source for many countries. The proposed paper will present a procedure (using numerical methods) for the design and analysis of Horizontal Axis Wind Turbine (HAWT) rotors. To ascertain the accuracy and to determine where further improvements could be initiated; numerical findings were then compared with published experimental test data and the compression showed an average deviation of less than 3% and therefore the simplifying assumptions made for the prediction of fluid behavior over an airfoil section was justified. Once the approach was validated and standardised a comprehensive airfoil design was produced. A computational fluid dynamic code coupled with a simple numerical algorithm aided the inverse design procedure. The final design was well proportioned and was theoretically able to meet the stated objective function and satisfied all the imposed constraints (manufacturing and geometrical). The geometrical data was then generated in a form suitable for manufacture using manually and numerically controlled machines.
Experimental Measurements and Computations of Heat Transfer and Flow Friction Factor in a Staggered Pin Fin Array
Authors: Ames Forrest E. , Solberg Christopher S. , Goman Michael D. , Curtis Daniel J. , Steinbrecker Bradley T.
Published: November 2020

This paper presents experimental measurements and CFD calculations for heat transfer and flow friction factor in a staggered pin fin array. The heat transfer and flow friction factor data are taken in a constant temperature facility and are acquired over a Reynolds number range of 1500 to 31,000. The array is comprised of eight rows of pins spaced at 2.5 diameters in the streamwise and spanwise directions with a pin height of two diameters. The heat transfer data are presented in terms of both average array data and row resolved data. The data accurately match the recent pin fin correlation of Chyu et at. [1] and extend its range to lower Reynolds numbers. The flow friction factor data accurately match the low and high Reynolds number data of Metzger et al. [2].

The steady state computations for a 2D and 3D representation of the geometry are performed and compared with archival correlations and the present data. The calculations are performed using a general purpose commercial solver (FLUENT 5.3 [3]) and apply the realizable k-ε model of Shih et al. [4] along with a two layer model which solves the k equation in the near wall region. Generally, the calculations perform relatively well with the 2D calculations matching the literature correlations slightly better than the 3D calculations.
Computational Study of a Two-Passage Turbine Guide-Vane Cascade With End-Wall Contouring
Authors: Zhu Bin , Lin Yu-Liang , Shih Tom I-P. , Oke Rohit , Simon Terry W. , Chyu Minking
Published: November 2020

CFD simulations based on the ensemble-averaged compressible Navier-Stokes equations, closed by two different turbulence models — the standard k-ε model with wall functions and the two-layer model of Chen and Patel — were performed to guide the design of a two-passage experimental setup, which models a linear cascade by using only three airfoils. Results generated show that the angle of the tailboards can be adjusted to give the same flow rates through the two passages. Results also show that once the flow rates are nearly the same, the pressure distributions become nearly periodic, indicating that the two-passage experimental setup does indeed mimic a linear cascade. The discrepancies between the two-passage experimental setup and a truly periodic linear cascade include the location of the stagnation zone about the airfoil’s leading edge and the shape of the pressure distribution in the trailing-edge region.
Computational Analysis of Pitch-Width Effects on the Losses of Turbine Blades
Authors: Xu C. , Amano R. S.
Published: November 2020

A three-dimensional computational code was developed for solving a time-averaged flow within a turbine blade-to-blade region using a novel time-marching method. A new concept of incorporating dissipation terms into the time derivative terms was proposed to allow the code to have the capability of handling both incompressible and compressible flows. The computational code was validated through comparisons with experiments in a turbine stator and was used to investigate the influence of secondary flow depending on different pitch-width ratios of the turbine blades. Detailed secondary flows as well as loss profiles in different sizes of root pitch-width ratio were presented. The results of this study provide useful information for evaluation of the secondary flow effects due to pitch-width ratio influence for the future turbine designs.
Generating Offsets That Are Homologous to Their Skeletons
Authors: Thompson David , Crawford Richard
Published: November 2020

In this paper we present a method for generating an offset surface from a subcomplex of a regular triangulation such that the surface has the same topology as the subcomplex. We assume that a subcomplex has been generated by specifying input points and their weights. The subcomplex may contain points, lines, triangles, and tetrahedra based on the values of the weights.

The offset from the subcomplex, or skeleton, is restricted to lie inside a union of balls centered around the input points with radii related to the weights of the input points. This restriction forces the offset and the skeleton to have the same homology. The homology groups are easy to compute for the skeleton. In this way, a designer can impose both geometric and topological constraints on a model. Also, the skeleton can be thought of as a graph to which design information can be attached; for instance, we show how the portion of the offset surface associated with each input point can be easily identified and used in lumped parameter analysis for simulations. Functional representations of a design might also be attached to the skeleton as well.
A Web-Based Distributed Product Realization Environment
Authors: Xiao Angran , Choi Hae-Jin , Kulkarni Rahul , Allen Janet K. , Rosen David , Mistree Farrokh , Feng Shaw C.
Published: November 2020

A web-based, a platform-independent software framework is developed to integrate distributed, heterogeneous software resources into an open product design/manufacturing system. We identify failings in previous systems, P2 and PRE-RMI, and propose systematic methods for the design of a software framework and implementation of a communication mechanism within that framework. An activity architecture of the product realization process is constructed based on the necessary interaction among engineers. This activity architecture is mapped onto a coordination architecture specifying the framework of the distributed software tools and resources. Thus the software framework is constructed based on the requirements of collaboration and communication between engineers. In addition, instead of exchanging information between engineers, the information flows are refined into message flows and data flows. Short commands and specific results are broadcast within product development groups in the form of messages, and large files are transferred directly as data flows. A prototype platform independent software framework, Web-based Distributed Product Realization Environment (WEB-DPR), is presented and its use in designing and manufacturing a high-speed robot arm is described.