bluuebunny/crossref_metadata_2025 huggingface dataset:
Kinematic Sensitivity of a Very Large Cable-Driven Parallel Mechanism
Authors: Bouchard Samuel , Gosselin Cle´ment M.
Published: June 2008

The LAR is a concept of a large orientable radiotelescope composed namely of a cable-driven parallel mechanism used to position and orient a feed plate. This document presents a first analysis of this mechanism’s orientation capability. The rotational kinematic sensitivity is defined here as the possible change in orientation occuring under a change in the actuation. After the application is described, common tools related to such problems are reviewed to explain why they are not totally suitable in this context. The velocity equation of the mechanism is then partitioned to obtain a quantification of the orientation kinematic sensitivity that is physically relevant. The study of a potential architecture’s rotational kinematic sensitivity is presented. Finally, the numerical and experimental validation of the approach are discussed.
Multiple Viewpoint Design Modelling Through Semantic Markup
Authors: Davies Daniel , McMahon Chris A.
Published: June 2008

This paper proposes an approach to multiple-viewpoint design modelling based on the concept of semantic markup of digital models of a design. The core of the concept is to make the engineering significance (semantics) of entities in a model of an artefact explicit through markup of the same model by engineers from multiple disciplines. Such markup, combined with current technologies that allow the computer interpretable specification of meaning and executable specifications of process, should allow a higher degree of automation of the manipulation of models within the design process, reducing the amount of user effort required. The development of the approach from concepts drawn from feature technologies and the Semantic Web is described along with experimental work carried out in a current generation commercial Computer-Aided Engineering (CAE) suite to test the feasibility of a structured markup for CAE models. The paper discusses the form that a fully realised semantic markup-based CAE system may take. Key elements of such a system are identified and the paper ends with a description of the planned development of the approach.
Case Study: User Adoption of a Product Configuration Management System at a Modular Playground Equipment Producer
Authors: Byron Bethany M. , Shooter Steven B.
Published: June 2008

Product platform and product family strategies place tremendous demands on the efficient capture, storage, and retrieval of information in the form of product data. The user’s adoption of an information management system for product families and mass customization is critical for allowing the system to perform as it ought. The following is a case study at a major modular playground equipment producer undergoing the implementation of a new graphical-based configurator for managing its mass customized products. The case study examines the proliferation of software packages to perform configuration and the flow of information in the configuration process. Next, the new configurator is evaluated on its new features to capture, store, and reuse configurations and its visual appeal. Last, the paper addresses the personal behaviors and training methods used for increasing adoption and their success.
INSIDES: A New Design and Simulation Platform for Virtual Prototyping in Automotive and Aerospace Industry
Authors: Schabacker Michael , Sabeur Moh , Vajna Sa´ndor
Published: June 2008

Human Machine Interactions Systems (HMI) are decisive for acceptance and safety of new cockpits in the automotive as well as in the aerospace industries. A new design and simulation platform called INSIDES will be presented where virtual cockpit prototypes are being built based on 3D CAD geometry e.g. from CATIA and integrated with logical interaction data derived from UML specifications. This new development platform enables the continuous validation and check of new interaction concepts by involving usability engineers in the very early stage of the development cycle. Since the simulation work is being done in the context of the entire aircraft cockpit / car interior with all instruments, control commands as well as displays devices a better validation of HMI systems can be achieved.
A Comparison of Probability Bounds Analysis and Sensitivity Analysis in Environmentally Benign Design and Manufacture
Authors: Aughenbaugh Jason Matthew , Duncan Scott , Paredis Christiaan J. J. , Bras Bert
Published: June 2008

There is growing acceptance in the design community that two types of uncertainty exist: inherent variability and uncertainty that results from a lack of knowledge, which variously is referred to as imprecision, incertitude, irreducible uncertainty, and epistemic uncertainty. There is much less agreement on the appropriate means for representing and computing with these types of uncertainty. Probability bounds analysis (PBA) is a method that represents uncertainty using upper and lower cumulative probability distributions. These structures, called probability boxes or just p-boxes, capture both variability and imprecision. PBA includes algorithms for efficiently computing with these structures under certain conditions. This paper explores the advantages and limitations of PBA in comparison to traditional decision analysis with sensitivity analysis in the context of environmentally benign design and manufacture. The example of the selection of an oil filter involves multiple objectives and multiple uncertain parameters. These parameters are known with varying levels of uncertainty, and different assumptions about the dependencies between variables are made. As such, the example problem provides a rich context for exploring the applicability of PBA and sensitivity analysis to making engineering decisions under uncertainty. The results reveal specific advantages and limitations of both methods. The appropriate choice of an analysis depends on the exact decision scenario.
On Specifying an Information Management Tool to Support Manufacturing Process Planning in Aerospace: A Case Study
Authors: El Hani M. A. , Rivest L. , Fortin C.
Published: June 2008

Facing increasing product complexity and pressure to reduce time to market, manufacturing process planning (MPP) engineers must be able to quickly access reliable information in order to make swift and correct decisions. Organizations therefore turn to information management tools, such as PDM (Product Data Management), MPM (Manufacturing Process Management) and ERP (Enterprise Resource Planning), to support their product development processes. These various information management tools compete by offering similar features, while MPP engineers have to manipulate multiple tools to access the information they need. This paper aims to take a fresh look at a fundamental question: what are the specifications of an ideal information management tool that would help MPP engineers efficiently define manufacturing work instructions (process plan) from the product definition? This paper thus presents the approach and the results of a research work conducted within the process planning department of a manufacturing company operating in the aerospace sector. The study was conducted so as to direct the effort toward documenting the MPP process and the MPP engineer’s information needs. The approach that is presented primarily relies on a comprehensive documentation and modeling of the MPP development process. Two processes have been modeled, a reference process of the MWI (Manufacturing Work Instructions) development and a change management process impacting the MWI development. These process models offer a sound basis to conduct an analysis of the MPP engineers’ information needs. This analysis next leads to the specifications of a Dashboard solution aimed at MPP engineers.
A Sequential Algorithm for Possibility-Based Design Optimization
Authors: Zhou Jun , Mourelatos Zissimos P.
Published: June 2008

Deterministic optimal designs that are obtained without taking into account uncertainty/variation are usually unreliable. Although reliability-based design optimization accounts for variation, it assumes that statistical information is available in the form of fully defined probabilistic distributions. This is not true for a variety of engineering problems where uncertainty is usually given in terms of interval ranges. In this case, interval analysis or possibility theory can be used instead of probability theory. This paper shows how possibility theory can be used in design and presents a computationally efficient sequential optimization algorithm. After, the fundamentals of possibility theory and fuzzy measures are described, a double-loop, possibility-based design optimization algorithm is presented where all design constraints are expressed possibilistically. The algorithm handles problems with only uncertain or a combination of random and uncertain design variables and parameters. In order to reduce the high computational cost, a sequential algorithm for possibility-based design optimization is presented. It consists of a sequence of cycles composed of a deterministic design optimization followed by a set of worst-case reliability evaluation loops. Two examples demonstrate the accuracy and efficiency of the proposed sequential algorithm.
Preliminary Results on Generating Assembly Sequences for Shape Display
Authors: Wolff Sebastien J. , Ebert-Uphoff Imme
Published: June 2008

Recently there has been much interest in developing shape display systems, i.e. systems that can generate, based on a virtual representation such as a CAD file, a physical shape that a user can touch. The approach considered here is to automatically assemble a shape from simple, identical building blocks using a robot. This paper describes preliminary research results on generating assembly sequences for this purpose, using a rule-based approach in order to deal with the huge search space due to the large number of components. While many of the details of the rule-based approach are discussed elsewhere, this paper focuses on analyzing and comparing the use of two different methods, the assembly method and the disassembly method in the z-direction, for assembly sequence generation.
Two Methodologies for Identifying Product Platform Elements Within an Existing Set of Products
Authors: Steva Elizabeth D. , Rice Elizabeth N. , Marion Tucker J. , Simpson Timothy W. , Stone Robert B.
Published: June 2008

As companies are pressured to decrease product development costs concurrently with increasing product variety, the need to develop products based upon common components and platforms is growing. Determining why a platform worked, or alternatively why it did not, is an important step in the successful implementation of product families and product platforms in any industry. Unfortunately, published literature on platform identification and product family analysis using product dissection and reverse engineering methods is surprisingly sparse. This paper introduces two platform identification methodologies that use different combinations of tools that can be readily applied based on information obtained directly from product dissection. The first methodology uses only the Bills-of-Materials and Design Structure Matrices while the second utilizes function diagrams, Function-Component Matrices, Product-Vector Matrices, and Design Structure Matrices to perform a more in-depth analysis of the set of products. Both methodologies are used to identify the platform elements in a set of five single-use cameras available in the market. The proposed methodologies identify the film advance and shutter actuation platform elements of the cameras, which include seven distinct components. The results are discussed in detail along with limitations of these two methodologies.
Assembly Configuration Synthesis Method for Discretely-Actuated Manipulators
Authors: Kemeny Deanne C. , Cipra Raymond J.
Published: June 2008

Discretely-actuated manipulators are defined in this paper as serial planar chains of many links where the actuation of one link with respect to the previous link occurs in one of three discrete positions. Because of the limited end-effector workspace, a link may be manually connected to the previous link in one of four 90° orientations to assist in generating a workspace corresponding to specific applications. Given an application workspace, the assembly configuration synthesis strategy presented here is a novel approach to determine the nominal configuration (all actuators in their 0° position) of the serial chain. The solved configuration will cover an application grid area using its discrete actuation with no change in nominal configuration. The unique application workspace, defined as a planar grid area, requires the end effector to be positioned somewhere within each specific element of the grid. The synthesis strategy is made up of three stages with each stage having tests that increase in computation and difficulty that a potential configuration must pass or be eliminated. Critical to the tests is the ability to quickly model and approximate the end-effector workspace of a configuration and a new method for this approximation is described.
A Single-Loop Approach for System Reliability-Based Design Optimization
Authors: Liang Jinghong , Mourelatos Zissimos P. , Nikolaidis Efstratios
Published: June 2008

An efficient single-loop approach for series system reliability-based design optimization problems is presented in this paper. The approach enables the optimizer to apportion the system reliability among the failure modes in an optimal way by increasing the reliability of those failure modes whose reliability can be increased at low cost. Furthermore, it identifies the critical failure modes that contribute the most to the overall system reliability. A previously reported methodology uses a sequential optimization and reliability approach. It also uses a linear extrapolation to determine the coordinates of the most probable points of the failure modes as the design changes. As a result, the approach can be slow and may not converge if the location of the most probable failure point changes significantly. This paper proposes an alternative system RBDO approach that overcomes the above difficulties by using a single-loop approach where the searches for the optimum design and for the most probable failure points proceed simultaneously. An easy to implement active set strategy is used. The maximum allowable failure probabilities of the failure modes are considered as design variables. The efficiency and robustness of the method is demonstrated on three design examples involving a beam, an internal combustion engine and a vehicle side impact. The results are compared with deterministic optimization and the conventional component RBDO formulation.
Finite Element Modeling of Coupled Flexible Multibody Dynamics and Liquid Sloshing
Authors: Wasfy Tamer M.
Published: June 2008

A time-accurate finite element model for simulating the fully-coupled dynamic response of flexible multibody systems and liquid sloshing in tanks is presented. The semi-discrete combined solid and fluid equations of motions are integrated using a time-accurate parallel explicit solver. The FE model consists of: hexahedral, beam, and truss solid elements; rigid bodies; joints; actuators; hexahedral incompressible fluid elements; and quadrilateral fluid-solid interface elements. The fluid mesh is modeled using a very light and compliant solid mesh which allows the fluid mesh to move/deform along with the tank using the Arbitrary Lagrangian-Eulerian formulation. The fluid’s free-surface is modeled using an acceptor-donor volume-of-fluid based algorithm. The motion of the solid and fluid is referred to a global inertial Cartesian reference frame. A total Lagrangian deformation description is used for the solid elements. The penalty technique is used to model the joints. Numerical simulations are presented for a half-filled tank supported by linear springs mounted on a test fixture.
Object-Oriented Modeling Environment for Simulating Flexible Multibody Systems and Liquid-Sloshing
Authors: Wasfy Tamer M.
Published: June 2008

An object-oriented graphical modeling environment for simulating the coupled dynamic response of flexible multibody systems and sloshing in liquid filled tanks is presented. The environment includes integrated pre-processor, solver, and post-processor. The environment can be used to model liquid tank bearing ground, air or space vehicles. The pre-processor allows constructing an object-oriented hierarchical “preliminary” model of the vehicle, tank, and terrain. The pre-processor includes a hierarchical model tree-editor along with interactive display of the model. It also includes an automatic mesh generator for generating the finite element (FE) model from the preliminary model. The FE model consists of hexahedral, beam, and truss solid elements, rigid bodies, joints, hexahedral incompressible fluid elements, and quadrilateral fluid-solid interface elements. The fluid mesh is modeled using a very light and compliant solid mesh which allows the fluid mesh to move/deform along with the tank using the ALE formulation. The fluid’s free-surface is modeled using a volume-of-fluid algorithm. A parallel explicit-time integration solver is used to generate the coupled dynamic response of the vehicle, tank, and fluid. The post-processor allows near-photorealistic visualization of animations of: vehicle, liquid free-surface, iso-surfaces, terrain and surroundings; colored/contoured surfaces; and surface/volume arrows. Users can control the visualization using the tree-editor or a clickable hierarchical list of natural-language commands.
A Screw-Theoretic Analysis Framework for Musculoskeletal Systems
Authors: Del Signore Michael J. , Bhatt Rajankumar M. , Krovi Venkat
Published: June 2008

In this paper, we examine the development of a framework for musculoskeletal system analysis, leveraging screw-theoretic techniques traditionally employed for the analysis of articulated multi-body systems (MBS). The case study of analysis of bite-and muscle-forces in the jaws of members of the felid (cat) family is intended to highlight the critical aspects. The underlying articulated structure and superimposed musculature of the felid jaws permit modeling as a parallel articulated MBS. Specifically, such systems share many common features with the subclass of cable actuated parallel MBS, including redundancy in actuation and unidirectional nature of actuation forces. The screw-theoretic model formulation is intended to enable development of a computationally efficient scheme for resolving such redundancy while retaining explicit geometric meaning in terms of lines of action, motions, and forces. The resulting low-order computational model is well suited for iterative “what-if” force optimization and muscle location studies. A MATLAB based GUI was developed and validated to help the user implement such iterative simulation-based muscle location studies in simulation or on a Hardware-in-the-Loop test-bed.
System Engineering Workshare Risk Analysis
Authors: Leung Peter , Ishii Kosuke , Benson Jan , Abell Jeffrey
Published: June 2008

In today’s global economy, companies develop products not only to target a single market, but to sell them to the entire world. Companies that realize the importance of collaborative design develop regional engineering centers worldwide to balance design variations while ensuring local market success. This paradigm enables diverse customer values to be integrated into products, but also introduces challenges in the management of work distribution. Typically, workshare decisions consider the capability and capacity of the regional centers. This strategy, however, overlooks the interdependence of the design systems, leading to delays and quality problems. This paper describes a method to formulate the workshare risk based on the couplings of the design system components and to evaluate overall workshare scenario. The method involves two relationships, Component-to-Component Coupling and Workshare Coupling, and a technique to combine these two relationships to measure the workshare risk. A simple case of hair dryer illustrates the concepts, while the method is serving actual global automotive development projects.
Dynamic Analysis of a Four-Span Rotor System With Nonlinear Oil-Films
Authors: Han Qingkai , Wang Li , Yao Hongliang , Ren Zhaohui , Wen Bangchun
Published: June 2008

A dynamical model of a four-span rotor system with multi-discs is built up, considering nonlinear oil-film forces, based on a 300 thousand kilowatt turbine-generator test rig. The bifurcation features of the system are studied with numerical integration technique. It is revealed that the proposed multi-span rotor model can express the fundamental dynamic characteristics of such a nonlinear system. Some bifurcations and chaotic motions may occur according to the calculated results. In coupling analyses, each rotor span also affects dynamically on the other, and the second span affects on the whole system in a serious way.
Large Nonlinear Random Responses of Spatially Non-Homogeneous Stochastic Shell Structures
Authors: To C. W. S.
Published: June 2008

This paper is concerned with large nonlinear random response analysis of spatially non-homogeneous stochastic shell structures under transient excitations. The latter are treated as nonstationary random excitation processes. The emphases are on (i) spatially non-homogeneous and homogeneous stochastic shell structures with large spatial variations, (ii) large nonlinear responses with finite strains and finite rotations, and (iii) intensive nonstationary random disturbances. The shell structures are approximated by the lower order mixed or hybrid strain based triangular shell finite elements developed earlier by the author and his associate. The nonstationary random nonlinear responses are evaluated by a procedure that consists of the stochastic central difference method, time co-ordinate transformation, and modified adaptive time scheme. Computationally, the procedure is very efficient compared with those entirely and partially based on Monte Carlo simulation, and is free from the limitations associated with those employing perturbation approximation techniques, such as the so-called stochastic finite element or probabilistic finite element method.
Synthesis of Variable Topology Bar Linkage Mechanisms
Authors: Amarnath Chitta
Published: June 2008

Several industrial applications require devices to operate in two or more phases with single degree of freedom motion in each phase. Variable topology mechanisms meet such requirements, one typical application of such devices being in circuit breakers. In this paper we discuss the synthesis of such devices for a variety (FSP, ISP and MSP) of motion specifications. The loci of pivots are determined.
Synthesis of Adaptive and Controllable Compliant Systems With Embedded Actuators and Sensors
Authors: Trease Brian P. , Kota Sridhar
Published: June 2008

This paper presents a framework for the design of a compliant system; that is, the concurrent design of a compliant mechanism with embedded actuators and embedded sensors. We focus on methods that simultaneously synthesize optimal structural topology and placement of actuators and sensors for maximum energy efficiency and adaptive performance, while satisfying various weight and performance constraints. The goal of this research is to lay a scientific foundation and a mathematical framework for distributed actuation and sensing within a compliant active structure. Key features of the methodology include (1) the simultaneous optimization of the location, orientation, and size of actuators concurrent with the compliant transmission topology and (2) the concepts of controllability and observability that arise from the consideration of control, and their implementation in compliant systems design. The methods used include genetic algorithms, graph searches for connectivity, and multiple load cases implemented with linear finite element analysis. Actuators, modeled as both force generators and structural compliant elements, are included as topology variables in the optimization. Results are provided for several studies, including: (1) concurrent actuator placement and topology design for a compliant amplifier and (2) a shape-morphing aircraft wing demonstration with three controlled output nodes. Central to this method is the concept of structural orthogonality, which refers to the unique system response for each actuator it contains. Finally, the results from the controllability problem are used to motivate and describe the analogous extension to observability for sensing.
Towards Development of a Non-Touch Man-Machine Interface for Intelligent Presenter-Audience Collaborative Environment
Authors: Vira Naren , Vira Shaleen
Published: June 2008

A novel, non-touch, screen pointing interface is proposed for the use of intelligent presenter/audience collaborative environment. The underlying methodology for detecting a virtual passive pointer is described. The passive pointer or device does not have any active energy source within it (as opposed to a laser pointer) and thus cannot easily be detected or identified. The modeling and simulation task is carried out by generating high resolution color images of a pointer viewing via two digital cameras with a popular three-dimensional (3D) computer graphics and animation program, Studio 3D Max by Discreet. These images are then retrieved for analysis into a Microsoft’s Visual C++ program developed based on the theory of image triangulation. The program outputs a precise coordinates of the pointer in the 3D space in addition to its projection on a view screen located in a large display/presentation room. The computational results of the pointer projection are compared with known locations specified by Studio 3D Max for different simulated configurations. High pointing accuracy is achieved: a pointer kept 30 feet away correctly hits the target location within a few inches. Thus, this technology is useful in a large setting where presenter-audience collaborative applications are needed.
A Comprehensive Metric for Evaluating Component Commonality in a Product Family
Authors: Thevenot Henri J. , Simpson Timothy W.
Published: June 2008

The competitiveness in today’s market forces many companies to rethink the way they design (and redesign) products. Instead of developing one product at a time, many manufacturing companies are developing families of products to provide enough variety for the marketplace while keeping costs relatively low. Although the benefits of commonality are widely known, many companies are still not taking full advantage of it when developing new products or redesigning existing ones. One reason is the lack of appropriate methods and useful metrics to assess a product family based on commonality and diversity. Although many component-based commonality metrics have been proposed in the literature, they do not (1) help resolve the tradeoff between commonality and diversity in a product family and (2) capture enough information to be completely useful during product family design and redesign. In this paper, we propose the Comprehensive Metric for Commonality (CMC) to evaluate the design of a product family on a 0–1 scale based on the components in each product, their size, geometry, material, manufacturing process, assembly, costs, and the allowed diversity in a family. To demonstrate the usefulness of this metric for product family benchmarking and redesign, the CMC is compared to six other component-based commonality indices. A CMC-based method is also proposed and applied to a family of staplers to (1) assess the level of commonality in the product family and (2) give recommendations for redesigning the product family.
A Survey of Various Encoding Schemes and Associated Placement Algorithms Applied to Packing and Layout Problems
Authors: Tiwari Santosh , Fadel Georges , Gantovnik Vladimir
Published: June 2008

In this paper, we investigate the current state-of-the-art in packing algorithms. The focus of this survey is on the different types of encoding schemes and associated placement techniques used to represent the layout of a set of objects. The encoding schemes are investigated with respect to their suitability to different types of packing problems, specific scenarios where a given representation may outperform others and their limitations. The different types of placement algorithms that can be used with a given encoding are described. Some common desirable characteristics that an encoding scheme should follow are also discussed. Finally a qualitative comparison of the various encoding schemes is presented to help in selecting a specific representation based on a set of criteria.
Vehicle Component Layout With Shape Morphing: An Initial Study
Authors: Dong Hong , Fadel Georges M. , Blouin Vincent Y.
Published: June 2008

This work focuses on incorporating component shape design into a vehicle configuration design or layout process. A concurrent design process consisting of performing layout design and simultaneous shape morphing of some select components is adopted to replace the traditional sequential design approach. The objective is to improve design efficiency and reduce design cost. Two important issues in the packing optimization with shape morphing problem are identified and studied: the morphing and the optimization. A parameterization-based morphing method and a mesh-based morphing method are implemented, and their advantages and disadvantages are discussed. To efficiently solve this complex problem, it is proposed to decompose it into a bi-level formulation: system level and component level. At the system level, the given functional objectives of the layout design problem are optimized with respect to component positions and orientations. At the component level, the shape of select components is morphed to minimize the overlap with other objects and the enclosure. By iterating between these two levels, the original problem is solved. This bi-level approach is intended to overcome the complexity of performing the placement simultaneously with the shape morphing.
The Duality Relation Between Mechanisms and Structures: A Different View
Authors: Ruiz-Lo´pez Ismael , Rico Jose´ M. , Cervantes-Sa´nchez J. Jesu´s , Gallardo Jaime , Orozco Horacio
Published: June 2008

In the last five years Prof. Shai has developed a comprehensive theory of the duality among different areas of engineering science, in particular between mechanisms and trusses. In this contribution, it is shown a different approach that, in the opinion of the authors, generalize the approach presented by Prof. Shai and clear some misconceptions.
Poisson Based Reuse of Freeform Features
Authors: Zhao Wei , Gao Shuming , Liu Yusheng
Published: June 2008

Due to the complexity, reuse of freeform features represented by B-spline is still an open issue. Based on Poisson equation, a novel approach to the reuse of freeform features represented by uniform rational B-spline (URBS) is proposed in this paper. In order to effectively support reuse, a new representation of freeform features is put forwarded, which is based on a new property about the odd URBS and consists of the principal control points, geometry context and basic surface of the feature. Based on the new representation, reuse of freeform features is achieved by updating the principal control points on the pasted area of the target surface using Poisson equation. The approach is implemented and some examples are given.
Generating Medial Axis by Local Adaptation For Polygons
Authors: Liu Yusheng , Yu Jie , Gao Shuming
Published: June 2008

Medial axis(MA) is a dimension-reduced representation for 2D/3D objects and widely used in finite element analysis(FEA). However it is very time consuming to computing MA from the scratch. In this study, a novel approach to generating the exact MA with local adaptation is proposed for polygons. The region where MA is to be changed is found out first. And then MA of the region is calculated and further it is combined with the unchanged MA to obtain the final MA for the whole part. The algorithm is implemented with ACIS 6.0 and some examples are given.
Robustness Analysis of Kinematic Covariance Propagation in Serial Manipulators
Authors: Wang Yunfeng , Chirikjian Gregory S.
Published: June 2008

In this paper we show that kinematic errors in serial manipulators propagate by convolution on the Euclidean motion group. When errors are small, covariances describing error probability densities can be propagated in place of explicitly performing the convolution. We investigate the robustness of covariance propagation formulas in the context of individual joint errors that are small, but result in overall end-effector errors that are not necessary small.
A Multi-Agent System for Modular Platform Design in a Dynamic Electronic Market Environment
Authors: Moon Seung Ki , Kumara Soundar R. T. , Simpson Timothy W.
Published: June 2008

Electronic markets and web-based supply chain management have improved traditional product development processes by increasing the participation of customers and applying various trading processes between companies and suppliers in a dynamic electronic market environment. A multi-agent system is an appropriate tool to implement a product development system in a distributed environment because of its flexibility, scalability, and adaptability. This paper introduces a multi-agent system (MAS) based on market mechanisms to support modular platform design. The agent architecture for the proposed MAS is described, including specific agent roles, knowledge, and strategies. In particular, a reputation mechanism is used to select stable and reputable modules for the platform by detecting and dismissing volatile modules in a dynamic electronic market environment. We demonstrate the implementation of the proposed MAS using a multi-agent development framework and how to use module reputation for selecting a module for the platform. Through experiments, we illustrate that the MAS can be used to design modules in a product platform using the proposed market mechanisms.
Data Mining and Fuzzy Clustering to Support Product Family Design
Authors: Moon Seung Ki , Kumara Soundar R. T. , Simpson Timothy W.
Published: June 2008

In mass customization, data mining can be used to extract valid, previously unknown, and easily interpretable information from large product databases in order to improve and optimize engineering design and manufacturing process decisions. A product family is a group of related products based on a product platform, facilitating mass customization by providing a variety of products for different market segments cost-effectively. In this paper, we propose a method for identifying a platform along with variant and unique modules in a product family using data mining techniques. Association rule mining is applied to develop rules related to design knowledge based on product function, which can be clustered by their similarity based on functional features. Fuzzy c-means clustering is used to determine initial clusters that represent modules. The clustering result identifies the platform and its modules by a platform level membership function and classification. We apply the proposed method to determine a new platform using a case study involving a power tool family.
Transforming a Traditional Introductory Materials Engineering Course to an Active, Learner Centered Environment Using Computer Based Technology Tools
Authors: Kitto Kathleen L.
Published: June 2008

Over the past three years, the Introduction to Materials Engineering and Science course at Western Washington University has been transformed from a traditional lecture delivery format course to an active, “learner centered” environment course. Several computer based technology tools have been used to make that transition possible. A Classroom Response System (CRS), the BlackBoard® Course Management System, MP3 audio files, and narrated, archived PowerPoint presentations have all been used to make better connections to the students and to make the course active and concept based. The initial assessment data is encouraging in that it shows improving student scores on traditional exam questions for classical problems, students more involved in their own learning, students rating teacher involvement and understanding of their needs higher, and a deeper conceptual understanding of the course material. In addition, the students were able to complete a much more challenging design problem at the end of the term. The drawback, of course, is that transforming the course and incorporating all these computer tools, active learning exercises and conceptual/peer learning into the course consumes an enormous amount of development time. Given that the potential gains for the students are really quite large and given that the technology used is already transforming our communication environment, the investment is a worthy one for any faculty member. This paper describes not only the specifications for the computer technology tools, but it also explains the needed development activities also necessary for reshaping the course, especially those needed for a concept based course. This approach is innovative because it combines the more traditional transformation approach to active learning with a computer tool centric approach to active and conceptual learning.
Towards a Suite of Problems for Comparison of Product Platform Design Methods: A Proposed Classification
Authors: Scott Michael J. , Garci´a Arenillas Juan Carlos , Simpson Timothy W. , Valliyappan Somasundaram , Allada Venkat
Published: June 2008

This paper presents the status of an ongoing project to develop a comprehensive suite of test problems suitable for comparing methods for scale-based product platform design. Despite a growing body of work in the area, there is no adequate set of testbed example problems for product platform design and benchmarking. A lack of consensus as to exactly what scale-based platform design entails has also hampered comparison of methods. In order to make a comprehensive test suite, we first need to define what different capabilities of platform design methods should be tested. To further this end, a classification scheme for example problems for scale-based platform design is presented. This simple taxonomy classifies example problems on the basis of two criteria: selection of platform architecture and incorporation of market demand. A brief review of examples from the literature shows that the existing examples are useful to test only a few of the capabilities of platform design methods. A new extension of an existing example, the design of a family of universal electric motors, is presented to test capabilities not covered by the existing set. This extended example is the first in our suite of examples.
LEA: Software System for Multimedia and Virtual-Reality Web-Based Education and Training
Authors: Wasfy Tamer M.
Published: June 2008

LEA (Learning Environments Agent) is a web-based software system for advanced multimedia and virtual-reality education and training. LEA consists of three fully integrated components: (1) unstructured knowledge-base engine for lecture delivery; (2) structured hierarchical process knowledge-base engine for step-by-step process training; and (3) hierarchical rule-based expert system for natural-language understanding. In addition, LEA interfaces with components which provide the following capabilities: 3D near photo-realistic interactive virtual environments; 2D animated multimedia; near-natural synthesized text-to-speech, speech recognition, near-photorealistic animated virtual humans to act as instructors and assistants; and socket-based network communication. LEA provides the following education and training functions: multimedia lecture delivery; virtual-reality based step-by-step process training; and testing capability. LEA can deliver compelling multimedia lectures and content in science fields (such as engineering, physics, math, and chemistry) that include synchronized: animated 2D and 3D graphics, speech, and written/highlighted text. In addition, it can be used to deliver step-by-step process training in a compelling near-photorealistic 3D virtual environment. In this paper the LEA system is presented along with typical educational and training applications.
Product Information Sharing in Collaborative Product Development With Web-Based 3D Visualization
Authors: Chu Chih-Hsing , Yuan Guo-Xun , Cheng Ching-Yi , Wu Che-Wen
Published: June 2008

This paper presents new applications of the Web-based 3D visualization technology in collaborative product development. Three software prototypes are developed with the technology for non-designer to interact with product model without the need of CAD tools. The first system allows the end customer to configure individual components of 3D assembly with a regular Web browser. It provides a simple approach to collecting the customer’s voices. Next, an integration framework is implemented that enables synchronous communications between CAD and on the shelf software tool of 3D visualization. Peer-to-peer design collaboration is thus realized. Finally, this research proposes a computation mechanism for online modification of design features based on a STL model. A Web 3D catalog is developed for customization of real industrial parts using the proposed mechanism. The implementation results of these prototypes indicate that Web-based 3D visualization is an effective interfacing technology to facilitate 3D information sharing for most product-centric activities in a simple and cost-effective manner.
Parametric Structural Shape and Topology Optimization Method With Radial Basis Functions and Level-Set Method
Authors: Wei Peng , Wang Michael Yu
Published: June 2008

In this paper, a parametric structural shape and topology optimization method is presented. To solving structure optimization problems, the level-set method has become a powerful design tool and been widely used in many fields. Combined with the Radial Basis Functions (RBF), which is a popular tool in function approximation, the method of level-set can be represented in a parametric way with a set of advantages comparing with the conventional discrete means. Some numerical examples are presented to illustrate its advantages.
On Optimal Design of Compliant Mechanisms for Specified Nonlinear Path Using Curved Frame Elements and Genetic Algorithm
Authors: Rai Ashok , Saxena Anupam , Mankame Nilesh D. , Upadhyay Chandra Shekhar
Published: June 2008

This paper discusses topology, shape and size optimization of fully compliant mechanisms for path generation applications using curved frame elements and genetic algorithm. The topology optimization problem is treated as a discrete ‘0-1’ problem wherein the elastic modulus is chosen as 0 or some pre-specified value, and no intermediate value in between. As the Young’s moduli are discrete topology design variables, function based genetic algorithm is employed for optimization. The size optimization variables are the lengths, in-plane widths and out-of-plane thicknesses of frame elements. Shape optimization is performed using the end slopes. Kirchhoff’s shallow arch beam theory is employed along with co-rotational geometrically nonlinear formulation. Synthesis examples are presented to demonstrate the applicability of min-max criterion proposed to achieve a curved path specified using precision points.
Computational Investigation of Gas- Solid Flow in PFBC Plant
Authors: Al-Hajeri M. H.
Published: June 2008

This paper reports a computational Fluid Dynamics (CFD) investigation for a high-temperature high-pressure filtration (ceramic candle filter). However parallel flow to the filter is considered in this study. Different face (filtration) velocities are examined using the CFD code, FLUENT. Particles ranging from 1 to 100 microns are tracked through the domain to find the height at which the particles will impinge on the filter surface. Furthermore, particle distribution around the filter (or filter cake) is studied to design efficient cleaning mechanisms. Gravity affect to the particles with various inlet velocities and pressure drop are both considered.
Robust Design of Compressor Blades Against Manufacturing Variations
Authors: Kumar Apurva , Keane A. J. , Nair P. B. , Shahpar S.
Published: June 2008

The aim of this paper is to develop and illustrate an efficient methodology to design blades with robust aerodynamic performance in the presence of manufacturing uncertainties. A novel geometry parametrization technique is developed to represent manufacturing variations due to tolerancing. A Gaussian Stochastic Process Model is trained using DOE techniques in conjunction with a high fidelity CFD solver. Bayesian Monte Carlo Simulation is then employed to obtain the statistics of the performance at each design point. A multiobjective optimizer is used to search the design space for robust designs. The multiobjective formulation allows explicit trade-off between the mean and variance of the performance. A design, selected from the robust design set is compared with a deterministic optimal design. The results demonstrate an effective method to obtain compressor blade designs which have reduced sensitivity to manufacturing variations with significant savings in computational effort.
How to Draw Euler Angles and Utilize Euler Parameters
Authors: Schwab A. L. , Meijaard J. P.
Published: June 2008

This article presents a way to draw Euler angles such that the proper operation and application becomes immediately clear. Furthermore, Euler parameters, which allow a singularity-free description of rotational motion, are discussed within the frame-work of quaternion algebra and are applied to the kinematics and dynamics of a rigid body.
Fuzzy Preference Evaluation for Hierarchical Co-Evolutionary Design Concept Generation
Authors: Li Wei , Jin Yan
Published: June 2008

Conceptual design is important but complex. Its success heavily depends on a designer’s individual experience and intuition. Design support tools are in need to assist designers to improve design quality and efficiency. However, to date there are few computational tools that are mature enough to provide effective assistance for design concept generation. One of the major reasons is that design information is inherently incomplete and subjective at the early stage of design. No effective evaluation methods have been devised to assess the connectivity between means (i.e., sub-solutions or function carriers) although it has an impact effect on system performance. In this paper, we propose a fuzzy reference model for conceptual design evaluation as part of our hierarchical co-evolutionary design concept generation based on function-means connectivity. An example of designing a simple mechanical transporter is presented to demonstrate the proposed approach.
System Identification and Response Prediction of Deteriorating Structures
Authors: Ng C. H. , Ajavakom N. , Ma F.
Published: June 2008

The lack of a fundamental theory of hysteresis is a major barrier to successful design of structures against deterioration associated with earthquakes, high winds, and sea waves. Development of a practical model of degrading structures that would match experimental observations is an important task. This paper has a two-fold objective. First, a superior system identification algorithm is devised to estimate the unspecified parameters in a differential model of hysteresis from experimental load-displacement traces. This algorithm is based upon the latest theory of genetic evolution and it will be streamlined through global sensitivity analysis. Second, the utility of identification of hysteresis is demonstrated through response prediction. Suppose a hysteretic model is generated with a given load-displacement trace. It will be shown experimentally that the model will predict the response of the same system driven by other cyclic loads. The requirements for precise prediction will be addressed. Through identification of hysteresis, it becomes possible to assess, for the first time in analysis, the performance of a real-life structure that has previously been damaged. In the open literature, there is not any other method that can perform the same task.