bluuebunny/crossref_metadata_2025 huggingface dataset:
Anderson Localization Phenomenon in Periodic Structures
Authors: Brasil Reyolando M.
Published: February 2014

We study the occurrence in structures of a phenomenon similar to Anderson localization. This the vibration modes localization in structures composed of several nominally identical lightly coupled modular substructures. In an ideal perfect model, the vibration modes are global in nature, spreading to the whole structure. In real structures there are no two completely identical segments. Constructive or loading imperfections generate slight variation of the dynamic characteristics of each module. As the level of disorder grows and coupling between modules becomes lighter, the resulting vibration modes change considerably. Vibration energy may become confined to a few segments. This is the Mode Localization Phenomenon. We present models of long modular planar trussed structures. Light coupling is considered between the initially identical modules. A certain degree of imperfection is introduced by adopting a slight variation in the loading of the modules. This will generate a small variation in the global stiffness of the system as the axial loads in the bars affect their Geometric Stiffness Matrices.
Motion Design Using Mimetic Words
Authors: Yamada Kaori , Koguchi Yohei , Taura Toshiharu
Published: February 2014

We are developing a methodology aimed at the design of new forms of motion that are more attractive to the human mind by blending motions obtained by mimicking the movement of natural objects. In this methodology, we focus on mimetic (reality-symbolic) words. Mimetic words express appearance and movements and can be understood as potential representations of those motions that are difficult to describe verbally. In this study, our objective is to create extremely creative and emotional motions from newly expressed mimetic words; just as new music is created from unique scores. First, we develop a method to decompose a newly expressed mimetic word into known mimetic words and actualise this method in the form of a tool. We then propose a procedure for creating a new motion from a newly expressed mimetic word.
A Fatal Accident Case and Lessons for Entertainment Engineering
Authors: Iino Kenji , Nakao Masayuki
Published: February 2014

On May 5th, 2007, a six-car stand-up roller coaster Fujin-Raijin II, during a ride, dropped one of its two wheel assemblies from the second car. Losing its balance, the second car tilted to the left by about 45 degrees. The rider in the left side of the front row jammed her head between the passenger support structure and the handrail of the maintenance walkway and was killed instantly. The next day, the Ministry of Land, Infrastructure, Transport and Tourism (MLIT) instructed a nationwide inspection of similar attractions.

Investigations revealed that the main axle had a crack caused by metal fatigue and the owner of the amusement park, bankrupt in 2009, had been running the coaster for 15 years without changing the axle and reporting “in good condition” upon visual inspection only. The applicable law required, and still does, annual testing with magnetic particles, ultrasound, or liquid penetrant. The axle, at the time of its failure, had only about 25% of cross-sectional area remaining intact where the crack had grown. A maintenance worker later reported looseness with the axle fit in the pressure-receiving hole. The fit was originally designed tight to receive the bending force.

People pay and wait in long lines for the excitement of unusual thrill from short amusement rides. The rides take passengers through unusual movements and G-forces to make them scream and laugh. Mechanical parts of the vehicles thus are subjected to unusual loading conditions. Machine design for such rides requires serious design reviews, failure analysis, frequent inspection, and thorough maintenance. Engineering ethics call for amusement park owners’ and workers’ awareness of design and operations for an unusual environment.
Analyzing Transdisciplinary Design Processes in Industry: An Overview
Authors: Gericke Kilian , Qureshi A. J. , Blessing Lucienne
Published: February 2014

Integrated product design and development in today’s highly competitive, demanding and economically challenging world is a complex process depending upon input of many individuals, groups, organizations and even communities, which collaborate to realize the product. Due to the multi-technology nature of modern products, the design process requires multi-disciplinary resources.

Engineering design literature provides an extensive knowledge base of product design processes, most of which are specific in an explicit or an implicit way to a specific discipline. This is because some time ago, the products were perceived to be rather mono-disciplinary.

Recently, design processes have been described for integrated products from inter-disciplinary and multi-disciplinary team perspective (e.g. [1]), however, they too take product specific and discipline specific point of view.

This paper takes a transdisciplinary perspective towards product design and presents results from an empirical study carried out to analyze the design process of different integrated products belonging to different disciplines/industrial segments; all of which involve multi-disciplinary or transdisciplinary involvement.

A framework based on key findings from the transdisciplinary consolidation of academic design process models presented by Gericke and Blessing and Eisenbart et al. is developed and used to provide answers to the following research questions:

• How well does the literature based trans-disciplinary design process apply to the trans-disciplinary industrial context?

• Are there similarities between design processes across organizations regarding presence of process stages and design states?

• Are there any elements that deviate from the literature-based framework?
Indices and Computational Strategy for Unmanned Ground Wheeled Vehicle Mobility Estimation and Enhancement
Authors: Gray Jeremy P. , Vantsevich Vladimir V. , Overholt Jim L.
Published: February 2014

The United States Army began developing Unmanned Ground Vehicles (UGV) in the early 1900’s. Concurrently, researchers developed and enhanced passenger and commercial ground vehicles. Although significant progress has been made for improving vehicle mobility for all ground vehicles throughout the past century, mobility has lacked a concise mutually agreed definition and analytical standardized criteria. The implementations of improved technologies, such as vehicle traction control, stability control, and torque vectoring systems require researchers to take a step back and reevaluate mobility criteria. UGVs require additional enhancement to include on-line mobility estimation since the vehicle cannot predict nor anticipate terrain conditions on their own prior to the vehicle traversing those conditions.

This paper analyzes methodologies researchers have employed for defining and improving vehicle mobility of wheeled vehicles. The analysis is done from a view point of concurrent mobility methodologies’ enhancement and applicability to wheeled UGVs.

This analysis is then used to develop off-line and on-line analytical criterion for mobility estimation, and to derive a strategy which can be applied to wheeled vehicles, both manned and unmanned. The on-line mobility estimation enables the UGV to make control changes as the events occur rather than after the event, causing the vehicle to then optimize its reaction to regain control.
Contact Force Analysis in Static Two-Fingered Robot Grasping
Authors: Cheng I , Liu C. H. , Wang Yin-Tien
Published: February 2014

Static grasping of a spherical object by two robot fingers is studied in this paper. The fingers may be rigid bodies or elastic beams, they may grasp the body with various orientation angles, and the tightening displacements may be linear or angular. Closed-form solutions for normal and tangential contact forces due to tightening displacements are obtained by solving compatibility equations, force-displacement relations based on Hertz contact theory, and equations of equilibrium. Solutions show that relations between contact forces and tightening displacements depend upon the orientation of the fingers, the elastic constants of the materials, and area moments of inertia of the beams.
Selection of Precision Machining Cutting Parameters via a Modified Efficient Global Optimization Approach
Authors: Aly Mohamed , Hamza Karim , Shalaby Mohammed , Nassef Ashraf O.
Published: February 2014

The primary objective in precision machining is usually to attain excellent dimensional accuracy and surface finish. In addition, complimentary objectives such as cost and production rate are also important. Proper selection of cutting parameters can profoundly affect both primary and secondary machining performance objectives. While simplified and/or empirical models exist for machining processes, none of those models provides accurate prediction of the dynamic cutting forces, which in turn govern the obtainable quality of the machined surfaces. Finite element analysis (FEA) via ABAQUS/Explicit is adopted in this paper for predicting the machining dynamic cutting forces. Rake and clearance angles, as well as cutting speed are set as the design variables for optimization. Since the machining model requires significant computational resources, economizing the number of FEA runs is desirable. The optimization approach adopted is based off Efficient Global Optimization (EGO), where Kriging models are trained to predict the underlying behavior of the machining process via a finite set of sample points. New sample points are then generated via a multi-objective genetic algorithm that seeks locations of optima and/or high uncertainty in the Kriging models. Machining performance of the new samples is then evaluated via FEA, the Kriging models are re-trained and the process is repeated until one of termination criteria is met. The application study presented is an orthogonal cutting test for ultra-precision micro-cutting using diamond tools.
Teaching Creative Mechanism Design by Integrating Synthesis Methodology and Physical Models
Authors: Yu Jingjun , Lu Dengfeng , Ding Xilun , Guo Weidong
Published: February 2014

Teaching young graduate students in the field of mechanical design has always been a challenging task. In particular, imparting some aspects on the creative design of mechanisms and robotics by far introduces additional difficulties. Because almost all existing systematic design or synthesis methodologies for the creative design, have a close connection with complicate mathematic tools. The objective of this paper is therefore to present a teaching approach based on an overview of pedagogical challenges of the authors in the past 8 years in teaching “Creative Design of Mechanisms and Robotics” to graduate students enrolled in mechanical engineering. One of the major components of the course is screw theory and its application to creative design of mechanical devices. In view of the fact that a large number of abstract concepts concerned, which heavily hinders the understanding of kernel knowledge, a reconfigurable model, based on the modularity design paradigm and latest study on flexures-based compliant mechanisms, is developed recently and integrated into impartation of a series of associating abstract knowledge. This paper outlines latest one-year experience of how the students are guided to learn the model-theory-integrated approach to creative design in a comparatively simple way.
The Use of the Strain Gradient Elasticity Theory in the Electrically Actuated Microbeam Problem: An Investigation on the Static and the Dynamic Response
Authors: Belardinelli Pierpaolo , Lenci Stefano
Published: February 2014

The main goal of this work is to investigate the static and the dynamic behaviour of an electrically-actuated microbeam modelled by means of the strain gradient elasticity theory. Considering the nonlinearities due to the mid-plane stretch and of the applied electric force, a numerical solution for the static response is obtained by the differential quadrature method including also the features introduced by the non-classical continuum theory. A parametric analysis confirms the well-known hardening effect generated by a tensile applied axial load and highlights the variation of the deflection with respect to the high-order material parameters. The reliability of the considered 1-d model is improved by taking also into account a correction for the electrical fringing field effects that slightly modifies the solution. Regarding the dynamics, a single-degree-of-freedom model is studied and the variation of the eigenfunction, used in the discretized problem, with respect to the higher-order length scale parameters, is analysed. The results, carried out from the 4th order Runge-Kutta numerical integration, show the softening/hardening behaviour of the device varying the beam model parameters.
Tooth Flank Breakage: Influences on Subsurface Initiated Fatigue Failures of Case Hardened Gears
Authors: Stahl Karsten , Höhn Bernd-Robert , Tobie Thomas
Published: February 2014

Pitting and tooth root breakage are typical fatigue failure modes of case hardened gears. Both failure types are usually initiated at the surface or close to the surface. General trends in modern gear industry, such as improved gear design with adequate flank modifications, high-quality gear materials and high-performance lubricants, modern manufacturing processes with additional post-processes as shot peening and superfinishing as well as advanced calculation methods, have allowed an optimized utilization of the allowable pitting and bending stress numbers in recent years. As a result of the increased power density, however, the stresses below the surface rise with the consequence of an increased risk of fatigue failure initiation in the material below the surface.

This paper describes main characteristics of a failure mode characterized by tooth breakages which start in the area of the active flank from cracks that are typically initiated at a considerable depth beneath the loaded flank surface. Based on theoretical and experimental investigations, relevant influence parameters related to gear design, operating conditions and material strength on the failure mode “Tooth Flank Breakage” will be discussed and basic principles of a developed calculation model to evaluate the risk of such failures presented. Finally, exemplarily experimental results from gear running tests, which failed due to flank breakage, are compared to the results of the new calculation model.
Shield Design for Shape-Shifting Surfaces
Authors: Lusk Craig , Perez Daniel E.
Published: February 2014

Shape-Shifting Surfaces (SSSs) are multilayered surfaces that are able to change shape while maintaining their integrity as physical barriers. SSSs are composed of polygonal unit cells, which can change side lengths and corner angles. These changes are made possible by each side and corner consisting of at least two different shields, or layers of material. As the layers undergo relative motion, the unit cell changes shape. In order for the SSS to retain its effectiveness as a barrier, no gaps can open between different layers. Also, the layers cannot protrude past the boundaries of the unit cell. Based on these requirements, a design space exploration was performed to determine, using equilateral triangle unit cells and triangular shields, the maximum deformation range of a unit cell. It was found that the triangular shields with maximum allowable deformation were right triangles with one of the angles being equal to 37.25 degrees and the adjacent side equal to 61% of the side length of the unit cell. The key contribution of this paper is a first algorithm for systematic SSS shield design. Possible applications for SSSs include protection, by creating body-armor systems; reconfigurable antennas able to broadcast through different frequencies; recreational uses, and biomedical applications.
Nonlinear Vibration Analysis and Approximate Solution of Micro-Beams
Authors: Saadatnia Zia , Askari Hassan , Younesian Davood , Esmailzadeh Ebrahim
Published: February 2014

Closed form expressions are obtained for the dynamic response of a micro-scale elastic beam in this paper. The nonlinear governing equation of motion is derived and solved using the Variational Iteration Method (VIM) and the Energy Balance Method (EBM). The frequency responses are presented in closed forms and their sensitivities with respect to the initial conditions are investigated. A number of numerical simulations are then carried out and the performance and validity of the solution procedure are evaluated in the time and frequency domain as well as in the phase plane. Accuracy of the solution procedure is studied by comparing the obtained results with those obtained from the exact solutions. Different effects of the nonlinear parameters and initial amplitude on the natural frequencies are also investigated in a parametric study. It is proved that VIM and EBM are simple and reliable techniques to solve the corresponding nonlinear differential equation.
Adding Non-Smooth Analysis Capabilities to General-Purpose Multibody Dynamics by Co-Simulation
Authors: Fancello Matteo , Masarati Pierangelo , Morandini Marco
Published: February 2014

Multi-rigid-body dynamics problems with unilateral constraints, like frictionless and frictional contacts, are characterized by nonsmooth dynamics. The issue of nonsmoothness can be addressed with methods that apply a mathematical regularization, called continuous contact methods; alternatively, hard constraints with complementarity approaches can be proficiently used.

This work presents an attempt at integrating consistently modeled unilateral constraints in a general purpose multibody formulation and implementation originally designed to address intrinsically smooth problems. The focus is on the analysis of generally smooth problems, characterized by significant multidisciplinarity, with the need to selectively include nonsmooth events localized in time and in specific components of the model. A co-simulation approach between the smooth Differential-Algebraic Equations solver and the classic Moreau-Jean timestepping approach is devised as an alternative to entirely redesigning a monolithic nonsmooth solver, in order to provide elements subject to frictionless and frictional contact in the general-purpose, free multibody solver MBDyn. The implementation uses components from the INRIA’s Siconos library for the solution of Complementarity Problems. The proposed approach is applied to several problems of increasing complexity to empirically evaluate its properties and versatility.

The applicability of the family of second-order accurate, A/L stable multistep integration algorithms used by MBDyn to nonsmooth dynamics is also discussed and assessed.
A Qualitative Numerical Analysis of Rotor-Casing Interactions in Centrifugal Compressors of Helicopter Engines
Authors: Meingast Markus B. , Batailly Alain , Legrand Mathias , Ousty Jean-Philippe
Published: February 2014

In experimental and numerical investigations of unilateral contact and friction induced rotor-casing interactions, a variety of complex phenomena is expected. Although most of the features of the structural responses can be explained within a simplifying linear framework, the nonlinear nature of contact and friction forces induce complicated responses which require an appropriate methodology to be conveniently analyzed. The presented work focuses on a thorough numerical exploration of such undesired events in an attempt to provide a dedicated systematic method of analysis.

Interaction simulations are carried out on the centrifugal compressor of a modern helicopter engine, for which it is assumed that the casing is rigidly distorted along a mathematical shape exhibiting distinct nodal diameters. The proposed work focuses on linear geometric aspects, such as cyclic symmetry and spatial aliasing of engine orders on nodal diameters as well as nonlinear attributes, such as sub- and super-harmonic participations in the response, in order to properly characterize the dynamics of the interaction.

The results are presented as space and time two-dimensional Fourier transforms of the numerically predicted response. Dominant responses are visible along time harmonics of the forcing frequency imposed by the assumed shape of the casing. It is observed that the participation of some nodal diameters in the response is a consequence of both the aliasing effect and superharmonic forcing terms.
A Power Dense Planetary Drive for Rotorcraft Applications
Authors: Ai Xiaolan , Orkin Curtis , Kruse Randy
Published: February 2014

Increasing power density is an on-going objective for engineers of fixed wing and rotary wing aircraft. The powertrain system is one of the largest contributors to the total mass of the aircraft and the geartrain is the largest contributor to the mass of the powertrain system. As such, the geartrain becomes the primary focus of many power density studies and is the focus of this paper.

Epicyclic geartrains are known to provide high power density and have become the geartrain of choice for the main power flow in virtually all aircraft designs. This paper presents a unique compound planetary design targeting a helicopter main gearbox transmission application. The design significantly improves power density through its innovative planet gear load-sharing configuration along with the utilization of high-performance materials for gears and bearings. Design studies were conducted comparing the power density of this new design to a baseline gearbox design. The results of these studies demonstrate an estimated 38% power density improvement over the baseline configuration. Of the total improvement, 86% is attributed to the novel load-sharing configuration while 14% is attributed to utilization of advanced materials and processes.
Novel Design Concept of Planar Litz Winding Without Via Using Folded Printed Circuit Board
Authors: Nomura T. , Seto K. , Toshiyuki K.
Published: February 2014

This paper discusses coil structures made from a folded flat sheet which is used for an inductor in high frequency operated battery chargers for future electrified vehicles. For AC loss reduction, a Litz wire is known to be a solution, however, since Litz wires are based on a cable type structure, planar type designs are desired for miniaturization and efficient fabrication of inductors. There exists a paper proposing planar type Litz windings using a printed circuit board for planar inductors. Our unit cell FEM analysis indicates that the stacking effect of multiple winding layers, i.e. the proximity effect between layers, was significant to its overall resistance and therefore the Litz wire pitch has to be much finer than the single board case. Thus, an effective Litz wire design, within our design requirements, requires a very fine strand width that goes beyond the fabrication capability of the vias, i.e. metalized through holes to connect different layers. In this paper, we propose novel planar Litz wire structure without vias by introducing a PCB folding technique by implementing a development chart for a coil structure with twisted strand bundle on one single sheet.
Descriptor-Based Methodology for Designing Heterogeneous Microstructural Materials System
Authors: Xu Hongyi , Li Yang , Brinson Catherine , Chen Wei
Published: February 2014

In designing a microstructural materials system, there are several key questions associated with design representation, design evaluation, and design synthesis: how to quantitatively represent the design space of a heterogeneous microstructure system using a small set of design variables, how to efficiently reconstruct statistically equivalent microstructures for design evaluation, and how to quickly search for the optimal microstructure design to achieve the desired material properties. This paper proposes a new descriptor-based methodology for designing microstructural materials systems. A descriptor-based characterization method is proposed to provide a quantitative representation of material morphology using a small set of microstructure descriptors covering features of material composition, dispersion status, and phase geometry at different levels of representation. A descriptor-based multi-phase microstructure reconstruction algorithm is developed which allows efficient stochastic reconstruction of microstructures for Finite Element Analysis (FEA) of material behavior. The choice of descriptors for polymer nanocomposites is verified by establishing a mapping between the finite set of descriptors and the infinite dimensional correlation function. Finally, the descriptor-based representation allows the use of parametric optimization approach to search the optimal microstructure design that meets the target material properties. To improve the search efficiency, this paper employs state-of-the-art computational design methods such as Design of Experiment (DOE), metamodeling, statistical sensitivity analysis, and multi-objective optimization. The proposed methodology is demonstrated using the design of a polymer nanocomposites system.
On the Synthesis of Hyperboloid Gear Drives and Technical Application
Authors: Abadjieva Emilia , Abadjiev Valentin , Kawasaki Haruhisa , Mouri Tetsuya
Published: February 2014

Hyperboloid drives (spatial skew-axes gears) are used to transform rotation between shafts with non-parallel and non-intersecting axes. In this paper the principles of mathematical modelling of a tooth contact synthesis for this common gearing case are discussed. The presented research shows that synthesis of hyperboloid gear drives can be achieved by application of mathematical model upon a pitch contact point. This approach is applied to the synthesis of spatial gear sets of Spiroid and Helicon types.
Reducing Vertical and Angular Accelerations With Nonlinear Asymmetrical Shock Absorber in Passenger Vehicles
Authors: Silveira Marcos , Pontes Bento R. , Balthazar José M.
Published: February 2014

The behaviour of linear and nonlinear shock absorbers are compared to diminish vertical and angular (pitch) accelerations of passenger vehicles, improving comfort by result. A 4-dof half-car model is used with three configurations of dampers: symmetrical, asymmetrical and front asymmetrical. The analyses use three standard road inputs and include variation of the severity parameter, the asymmetry ratio and the velocity of the vehicle. The comparison shows that the asymmetrical system, with nonlinear characteristics, tends to have a smoother and more progressive behaviour. The results show that the use of the front asymmetrical system diminishes angular oscillations of the vehicle. As lower levels of acceleration are essential for improved ride comfort, the use of asymmetrical systems for vibrations and impact absorption is a superior choice for passenger vehicles.
Sustainable Process Analytics Formalism: A Case Study of Book Binding System for Energy Optimization
Authors: Kim Duck Bong , Shao Guodong , Brodsky Alexander , Consylman Ryan
Published: February 2014

Energy is considered as one of the important factors for manufacturers to achieve the sustainability objective. To improve energy efficiency in manufacturing, optimization techniques are essential to provide decision support. However, formulating and solving energy optimization in manufacturing is still time-consuming and difficult due to its complexity with a broad scope. In addition, it is a challenging task since it requires substantial development efforts and modeling expertise. To address this drawback, Sustainable Process Analytics Formalism (SPAF) is proposed to facilitate the modeling and optimization. In this paper, SPAF will be applied to a case study of energy optimization for a book binding production system for its feasibility validation. The knowledge of process flow, data, and metrics of the case study is represented using SPAF, and a preliminary analysis of optimization results was performed.
A Framework for the Application of Adaptronic Solution Principles
Authors: Inkermann David , Stechert Carsten , Vietor Thomas
Published: February 2014

There is an increasing need for products that are able to react to changing operating conditions and user demands to achieve a high level of performance. Adaptronic solutions allow for property adjustments without major effects on system weight and size when they are applied in early phases of the design process. Since a framework for the design of adaptronic solutions is not yet established, this paper introduces an initial procedure and principles to provide design knowledge. The paper first gives an overview on adaptronics and adaptability as well as principles and guidelines for designing adaptable products. Fifteen adaptronic solution principles are derived from adaptronic solutions to provide the information needed for the design of adaptable products. A framework is proposed to apply the introduced principles within the conceptual design phase to avoid design conflicts and undesired effects. Finally, the framework is used for the design of adaptive joints for robotic applications.
A Combined Speed and Finite-Time Yaw Controller for an Underactuated Unmanned Surface Vessel Using Way-Point Navigation
Authors: Baker Brendan , Qian Chunjiang , Nowak Brent
Published: February 2014

This paper focuses on the speed and yaw control problem for an underactuated unmanned surface vessel (USV) with only two propellers navigating through multiple way-points using the line-of-sight (LOS) algorithm. The speed and yaw dynamics are transformed into a cascaded nonlinear system that can be reduced to the stabilization control problem of the surge and yaw subsystems. The proposed surge speed controller uses a distance and heading error feedback control to vary its speed accordingly while the heading subsystem is stabilized via a finite-time controller. Comparisons of the traditional yaw rate stabilization control techniques are made with the proposed finite-time controller and shown to be inferior to the finite-time controller in terms of convergence rate and robustness. The stability and effectiveness of the proposed control system is demonstrated and validated by simulation results of a modeled kayak.
Continuous Solution for Boundary Value Problems on Non Rectangular Geometry
Authors: Venkataraman P.
Published: February 2014

Boundary value problems on a rectangular domain can also be solved through non domain discretization techniques. These methods yield high order continuous solutions. One such method, based on Bézier functions and developed by the author, can solve linear, nonlinear, ordinary, partial, single, or coupled systems of differential equations, using the same consistent approach. In this paper the technique is extended to non-rectangular domains. This provides a mesh free alternate to the family of finite element or finite difference methods that are currently used to solve these problems. The problem requires no transformation and the setup is direct and simple. The solution is established by minimizing the error in the residuals of the differential equations and the error in the boundary conditions over the domain. In addition, the high order continuous solution is available in polynomial form. The solution is obtained through the application of standard unconstrained optimization. Three examples are discussed. The first example is Poisson’s equation in a circular region. The second is the solution to the Laplace equation over a five sided domain with one of the sides circular. The third example is a simple nonlinear extension of the differential equation in the second example. Directly accommodating a nonlinear boundary value problem, without any change, is the strength of this approach. Solutions are compared with ones from finite elements analysis where available. This approach can provide continuous solution to problems where previously only discontinuous solutions were available.
Pareto Front Identification via Objective Vector Jacobian Matrix Singularity
Authors: Brown Brandon , Singh Tarunraj , Rai Rahul
Published: February 2014

This paper presents a method to identify the exact Pareto front for a multi-objective optimization problem. The developed technique addresses the identification of the Pareto frontier in the cost space and the Pareto set in the design space for both constrained and unconstrained optimization problems. The proposed approach identifies a n – 1 dimensional hypersurface for a multi-objective problem with n cost functions, a subset of which constitute the Pareto front. The n – 1 dimensional hypersurface is identified by enforcing a singularity constraint on the Jacobian of the cost vector with respect to the optimization parameters. Since the boundary is identified in the design space, the relation of design points to the exact Pareto front in the cost space is known. The proposed method is proven effective in the Pareto identification for a set of previously released challenge problems. Six of these examples are included in this paper; 3 unconstrained and 3 constrained.
Haptic Device With Spherical MR-Brake for Wrist Rehabilitation
Authors: Antolini Michele , Köse Orhun , Gurocak Hakan
Published: February 2014

This research explored the development of a new haptic device for wrist rehabilitation therapy. Specifically, the therapy requires providing resistive forces against the adduction/abduction, flexion/extension of the wrist and pronation/supination of the forearm. The new haptic device employs a spherical magnetorheological brake (MR-brake). This brake was developed by our research group for a previous study and is the only one of its kind. It resembles a typical ball-joint with 3 degrees of freedom (DOF). It can apply high levels of variable resistive force in a very compact single actuator. The new device was coupled to the spherical MR-brake via linkages so that the virtual center of rotation was placed at the center of the patient’s wrist. Compared to similar devices that use motors, conventional rotary MR-brakes or hybrid MR-motor actuators, our device has the advantage of using just a single compact actuator to control all 3 DOF. The interface is inherently safe in such a rehabilitation application as the MR-brakes are passive devices. Details of the design, the MR-brake and a series of experiments to characterize the device are presented. The experimental results indicate minimal backlash in the linkages and the device can provide easily controllable resistive forces in its range of motion. Such a haptic interface is promising since it can enable a computer-controlled and -monitored rehabilitation therapy with a virtual training environment.
Creating by Imagining: Use of Natural and Intuitive BCI in 3D CAD Modeling
Authors: S. Sree Shankar , Verma Anoop , Rai Rahul
Published: February 2014

Since its inception, computer aided 3D modeling has primarily relied on the Windows, Icons, Menus, Pointer (WIMP) user interface. WIMP has rarely been able to tap into the natural intuitiveness and imagination of the user which accompanies any design process. Brain-computer interface (BCI) is a novel modality that uses the brain signals of a user to enable natural and intuitive interaction with an external device. The BCI’s potential to become an important modality of natural interaction for 3D modeling is almost limitless and unexplored. In theory, using BCI one can create any 3D model by simply thinking about it. This paper presents a basic framework for using BCI as an interface for computer aided 3D modeling. This framework involves the task of recording and recognizing electroencephalogram (EEG) brain wave patterns and electromyogram (EMG) signals corresponding to facial movements. The recognized EEG/EMG brain signals and associated keystrokes are used to activate/control different commands of a CAD package. Eight sample CAD models are created using the Emotiv EEG head set based BCI interface and Google SketchUp and presented to demonstrate the efficacy of the developed system based on the framework. To further exhibit BCI’s usability, human factor studies have been carried out on subjects from different backgrounds. Based on preliminary results, it is concluded that EEG/EMG based BCI is suitable for computer aided 3D modeling purposes. Issues in signal acquisition, system flexibility, integration with other modalities, and data collection are also discussed.
Intuitive 3D Computer-Aided Design (CAD) System With Multimodal Interfaces
Authors: Nanjundaswamy V. G. , Kulkarni Amit , Chen Zhuo , Jaiswal Prakhar , S. Sree Shankar , Verma Anoop , Rai Rahul
Published: February 2014

The existing interfaces for 3D CAD modeling softwares use 2D subspace inputs such as x and y axes of mouse to create 3D models. These existing interfaces are inherently modal because one needs to switch between subspaces, and disconnects the input space from modeling space. This makes existing interfaces tedious, complex, non-intuitive and difficult to learn. In this paper, a multi-sensory, interactive, and intuitive 3D CAD modeling interface is presented to address these shortcomings. Three different modalities (gestures, brain-computer interface, and speech) have been used for creating interactive and intuitive 3D CAD modeling interface. DepthSense® camera from SoftKinetic is used to recognize gestures, EEG Neuro-headset from Emotiv® is used for acquiring, and processing neuro-signals and CMU Sphinx is used for recognizing and processing speech. Multiple CAD models created by several users using the proposed multi-modal interface are presented. In conclusion, the proposed system is easier to learn and use as compared to the already existing systems.
Design Methods for Integrated Design of Blast Resistance Panels and Materials
Authors: Jang Sungwoo , Choi Hae-Jin
Published: February 2014

Integrated Materials and Products Design (IMPD) differs in the way that materials as well as product layout are designed or optimized in a concurrent manner to meet design requirements. IMPD allows the specific performance required in a product to be achieved by tailoring materials and product, since system performance will not be limited by a pre-chosen material employed in conventional, material-selection-based design. In this study, Blast Resistance Panels (BRPs) with square honeycomb core are designed based on this new design approach to further enhance the performance of BRPs.

We employ multi-level design methods for the integrated design of blast resistance panels and materials. Along with the traditional multi-level optimization of BRP, another design approach, Analytical Target Cascading (ATC) is introduced for a comparative design study in the BRP design. In this article, we compare the design results and design exploration efficiency of the two multi-level design methods in designing the blast resistance panels as well as those materials. We also discuss the advantage and disadvantage of the methods observed in this study.
Study on a New Kind of 6-Degree of Freedom Parallel Earthquake Simulator
Authors: Ma Chunxiang , Zheng Miaoqi , Huang Xu , He Jun , Chen Jie , Gao Feng
Published: February 2014

In this paper, a kind of 6-degree of freedom parallel earthquake simulator is proposed, which has 28 -input, two types of the branches and the redundant and fault-tolerant actuators. Based on the theory of the parallel mechanism, the mechanism of the 6-degree of freedom parallel earthquake simulator with 28 -input and the redundant and fault-tolerant actuators is constructed. The kinematic model of the earthquake simulator is established by D-H method. The kinematic simulation and the dynamic simulation of the earthquake simulator are carried out with ADAMS software. Finally, FEM model of the earthquake simulator is given and the modal analysis of the earthquake simulator is made with ANSYS software.
User Study: Influence of Number of Design Errors on Ability to Predict Performance With and Without Controls
Authors: Thimmaiah Somaiah , Phelan Keith , Summers Joshua D.
Published: February 2014

Design reviews are typically used for three types of design activities: 1) identifying errors, 2) assessing the impact of the errors, and 3) suggesting solutions for the errors. This experimental study focuses on understanding the second issue as it relates to the number of errors considered, the existence of controls, and the level of domain familiarity of the assessor. A set of design failures and associated controls developed for a completed industry sponsored project is used as the experimental design problem. Non-domain individuals (students from an undergraduate psychology class), domain generalists (first year engineering students), and domain-specialists (graduate mechanical engineering students) are provided a set of failure modes and asked to estimate the likelihood that the system would still successfully achieve the stated objectives. Primary results from the study include the following: the confidence level for all domain population decreased significantly as the number of design errors increased (largest p-value = 0.0793) and this decrease in confidence is more significant as the design errors increase. The impact on confidence is less when solutions (controls) are provided to prevent the errors (largest p-value = 0.0334), the confidence decreased faster for domain general engineers as compared to domain specialists (p = <0.0001). The domain specialists showed higher confidence in making decisions than domain generals and non-domain generalists as the design errors increase.
An Investigation Into How Structural Design Process Performed by Industrial Design Engineering Trainees Unfolds
Authors: Opiyo Eliab Z.
Published: February 2014

This paper presents a study conducted to investigate how structural design process performed by industrial design engineering trainees unfolds. The focus was specifically on structural design of industrial design engineering products, a class of consumer durables designed to endure short and long term regular usage by human beings. The study consisted of a questionnaire survey and interviews, as well as observation of structural design processes. One hundred and eighty two subjects participated in the questionnaire survey. The study gave us some clues on how structural design processes proceed in real life and on how a formal method for structural design may ideally be structured. Furthermore, the results of this study suggest that it is not always important to follow a strictly structured order in executing certain structural design activities. Specifically, sequential execution of the mid-way activities of materials selection, process selection and engineering analysis is somewhat impractical. A linear-cyclic structural design procedural process model is composed based on the findings of the investigation. However, since the study involved only a handful of selected structural design processes, we cannot draw out definitive conclusions regarding the applicability of the composed process model or suggest how strict the process steps must be adhered to. Further studies are needed to verify the validity of the findings of this investigation.
Time Domain Analysis of the Smith Predictor in Case of Parameter Uncertainties: A Case Study
Authors: Hajdu Dávid , Insperger Tamás
Published: February 2014

Time domain representation of the original Smith Predictor is presented for systems with feedback delays. It is shown that if the parameters in the internal model of the predictor are not equal to the parameters of the real system, then the dimension of the closed loop system is double of the dimension of the open-loop system. Furthermore, the time-domain representation of the corresponding control law involves terms of integrals with respect to the past similarly to the Finite Spectrum Assignment control technique. The results are demonstrated for a second order system (pendulum) subjected to the Smith Predictor. It is demonstrated that stability diagrams can be constructed using the D-subdivision method and Stepan’s formulas. The sensitivity of the stability properties with respect to the parameter uncertainties in the predictor’s internal model is analyzed. It is shown that the original Smith Predictor can stabilize unstable plants for some extremely detuned internal model parameters. Thus the general concept that the Smith Predictor is not capable to stabilize unstable systems is technically not true.
Freeform Origami Tessellations by Generalizing Resch’s Patterns
Authors: Tachi Tomohiro
Published: February 2014

In this research, we study a method to produce families of origami tessellations from given polyhedral surfaces. The resulting tessellated surfaces generalize the patterns proposed by Ron Resch and allow the construction of an origami tessellation that approximates a given surface. We will achieve these patterns by first constructing an initial configuration of the tessellated surfaces by separating each facets and inserting folded parts between them based on the local configuration. The initial configuration is then modified by solving the vertex coordinates to satisfy geometric constraints of developability, folding angle limitation, and local non-intersection. We propose a novel robust method for avoiding intersections between facets sharing vertices. Such generated polyhedral surfaces are not only applied to folding paper but also sheets of metal that does not allow 180° folding.
Topological Synthesis and Integrated Kinematic-Structural Dimensional Optimization of a Ten-Bar Linkage for a Hydraulic Rescue Spreader
Authors: Sullivan Thomas , Van de Ven James D.
Published: February 2014

Hydraulic rescue spreaders are used by emergency response personnel to extricate occupants from a vehicle crash. A lighter and more portable rescue spreader is required for better usability and to enable utilization in a variety of scenarios. To meet this requirement, topological synthesis, dimensional synthesis, and an optimization were used to develop a solution linkage. The topological synthesis technique demonstrates that ten links are the minimum possible number that achieves the desired motion without depending primarily on rotation of the spreader jaws. A novel integrated kinematic-structural dimensional synthesis technique is presented and used in a grid-search optimizing the linkage dimensions to minimize linkage mass. The resulting ten-bar linkage meets or exceeds the kinematic performance parameters while simultaneously achieving a near-optimum predicted mass.
Automatic Verification of Modeling Rules in Systems Engineering for Mechatronic Systems
Authors: Kaiser Lydia , Dumitrescu Roman , Holtmann Jörg , Meyer Matthias
Published: February 2014

Mechatronics is the close interaction of mechanics, electronics, control engineering and software engineering. The increasing complexity of mechatronic systems results in a challenging development process and particularly requires a consistent comprehension of the tasks between all the engineers involved. Especially during the early design phases, the communication and cooperation between the mechanical, electrical, control and software engineers is necessary to establish a basis for efficient and effective product development. The approach of Model-Based Systems Engineering focuses on this aspect by means of an abstract but superordinate system model. It enables a holistic view of the system. The system model can be specified using the Systems Modeling Language (SysML). The language allows many degrees of freedom to specify a fact, bearing in mind that different system architects can specify the same fact in different ways. This leads to system models that can be interpreted in many ways. Thus, these models are hard to consistently compare and interpret, resulting in communication issues. In order to tackle this problem, we present a concept that uses modeling rules supporting model comparability. We formalize them by means of checks implemented in the programming language Java and the Object Constraint Language (OCL) in order to automatically verify the system model’s compliance with these rules.