bluuebunny/crossref_metadata_2025 huggingface dataset:
Customizing Next-Generation Multidisciplinary Product Realization Frameworks
Authors: Bajaj Manas , Fulton Robert , Peak Russell
Published: June 2008

Technological advancements have made the product realization process assume multi-disciplinary proportions. The information models associated with a product have grown richer not only in content but also in semantics and though derived from diverse sources, they are interdependent and need to interact. This paper envisions customizing Product Realization Frameworks (PRFs) as a synergistic aggregation of rich information models that cater to product development. It proposes a semantic model to organize product realization information and then develops a “Three-Tier Architecture” to enable the customization of Product Realization Frameworks for individual business needs of engineering enterprises. A prototype PRF for an “Optimized printed wiring board (PWB) stack-up design” problem has been implemented using the concepts proposed. The paper points towards the inherent flexibility of the proposed architecture to cater to varied extensions of the stack-up design problem.
UMASST: A New Teaching Tool for Stress State Transformation
Authors: Yu Mei , Grosse Ian R. , Woolf Beverly , Lindenmuth Mike
Published: June 2008

This paper presents UMASST, the UMASS Stress State Transformation tutor. UMASST is a multimedia tutor based on active engagement of the learner and the use of visualization. The development of UMASST was informed by cognitive models of human reasoning, research on how people learn and computing technology. As a multimedia Director® and web-based application with knowledge-centered and assessment-centered modules, the UMASST targets improving understanding and mastery of transformation of stress states in mechanics of materials. In the knowledge-centered modules learners receive in-depth information on physical meaning and real-life applications of stress state transformations before their understanding is assessed in interactive workshops. The assessment-centered modules assist novices in assessing themselves on the subject domain. Assessment results show that the current efficacy of the UMASST tutor is above that of in-class lectures. Future work will include a learner-centered module customizing learning process by considering learners’ individual backgrounds.
Using Spreadsheet Modules to Augment the Design of Worm Gear Geometry
Authors: Shoup Terry E.
Published: June 2008

This paper presents an easy-to-use spreadsheet module in Microsoft Excel to solve the transcendental equation associated with the design of worm geometry for a worm-gear speed reducer. The module makes use of an embedded Visual Basic numerical optimization algorithm to determine the number of solutions possible and then finds all solutions that satisfy the fundamental laws of worm gearing. This module allows the quick implementation of designs that are more accurate than was previously possible by traditional trial and error methods. The method will be particularly helpful to students and inexperienced designers who first encounter the need to design a worm gear combination. The paper will present an example application to illustrate the use of the module.
Using PC-Based Data Acquisition to Teach Data Analysis and Statistical Process Control
Authors: Khosrowjerdi M. , Mindek Richard B.
Published: June 2008

An undergraduate laboratory has recently been developed to expose junior mechanical engineering students to the concept, components and operation of data acquisition boards, PC-based data acquisition, analysis and control. The laboratory, which has been taught during the last two fall semesters, consists of the compression testing of golf ball cores using a Riehle compression tester, and analysis of the collected data using digital signal processing techniques and statistical process control (SPC). Student feedback to date suggests the labs have had a positive impact on student learning and underline the importance of including the topic of PC-based data acquisition and analysis in an undergraduate engineering curriculum.
On Parametric Analysis of Differential Hysteresis
Authors: Ma F. , Ng C. H. , Zhang H. , Bockstedte A. , Foliente G. C. , Paevere P.
Published: June 2008

The extended Bouc-Wen differential model is one of the most widely accepted phenomenological models of hysteresis in mechanics. It is routinely used in the characterization of nonlinear damping and in system identification. In this paper, the differential model of hysteresis is carefully re-examined and two significant issues are uncovered. First, it is found that the unspecified parameters of the model are functionally redundant. One of the parameters can be eliminated through suitable transformations in the parameter space. Second, local and global sensitivity analyses are conducted to assess the relative sensitivity of each model parameter. Through extensive Monte Carlo simulations, it is found that some parameters of the hysteretic model are rather insensitive. If the values of these insensitive parameters are fixed, a greatly simplified model is obtained.
Non-Conservative and Conservative Loads in Geometrically Nonlinear Shells
Authors: To Cho W. S. , Liu Meilan L.
Published: June 2008

Responses of geometrically nonlinear shell structures under combined conservative and non-conservative loads are investigated and presented in this paper. The shell structures are discretized by the finite element method and represented by the hybrid strain based three node flat triangular shell elements that were developed previously by the authors. The updated Lagrangian formulation and the incremental Hellinger-Reissner variational principle are employed. Features such as large or small strain deformation, finite rotation, updated thickness so as to account for the “thinning effect” due to large strain deformation, and inclusion or exclusion of the mid-surface director field are incorporated in the finite element formulation. Representative results of two examples are included to demonstrate the capability, accuracy and efficiency of the computational strategy proposed.
Supply Chain Simulation Modeling Using the Supply Chain Operations Reference Model
Authors: Hermann Jeffrey W. , Lin Edward , Pundoor Guruprasad
Published: June 2008

Simulation is a very useful tool for predicting supply chain performance. Because there are no standard simulation elements that represent accurately the activities in a supply chain, there exist a variety of approaches for developing supply chain simulation models. To improve this situation, this paper describes a novel supply chain simulation framework that follows the Supply Chain Operations Reference (SCOR) model. This framework has been used for building powerful simulation models that integrate discrete event simulation and spreadsheets. The simulation models are hierarchical and use submodels that capture activities specific to supply chains. The SCOR framework provides a basis for defining the level of detail in a way as to include as many features as possible, while not making them industry specific. This approach enables the reuse of submodels, which reduces development time. The paper describes the implementation of the simulation models and how the submodels interact during execution.
A Method for Supporting Creative Interaction During Collaborative Design Processes
Authors: Kobayashi Masakazu , Yoshimura Masataka , Nishiwaki Shinji , Izui Kazuhiro
Published: June 2008

This paper discusses design problems where creative solutions are required, and proposes a support system for a group of designers engaged in collaborative design processes. There are two merits to such collaboration: the sharing of information and knowledge among members of the design team and the promotion of designer creativity during interactive communication. In the current engineering field, the extent of expertise that one designer can master is narrower than the total area of expertise needed to achieve a successful product design. To achieve practical designs, designers must work cooperatively and share the requisite information and knowledge as the design is developed and optimized. During collaboration, designers exchange various types of information, such as knowledge, ideas, opinions and so on, and this exchange can stimulate their creativity, enabling the generation of more creative ideas than would be possible when working alone. This paper focuses on the enhancement of designer creativity and constructs systems that maximize it during the collaborative design process. This research consists of three steps: formation of a basic model of creative group activity, construction of a support system for creative collaboration based on the basic model, and comparative experiments, conducted to investigate the effectiveness of the proposed support system.
Elements and Techniques to Develop a Distributed Design Framework
Authors: Chen Zhiqiang , Siddique Zahed
Published: June 2008

The direction of mechanical design is now experiencing the trends of resource globalization, design customization and demand for cheap computing. Successful integration and collaboration are very important for design systems. Currently many researches focus on client-server structure to keep the data consistent and neutral. This paper discusses the issues and techniques to build a framework to support integration and collaboration in a distributed design environment. Overview of the system architecture and modules of the framework are presented to explain the method for CAD software wrapping and management of design models. The concept of a function block module to integrate different analysis tools and a search engine to find the analysis path for design problems are also presented. A reverse engineering project is used as an example to describe how design process works in a distributed manner.
Modeling and Management of Design Requirements in Product Development Life Cycle
Authors: Fu M. W. , Lu W. F.
Published: June 2008

The traditional product development strategy has shifted from first-to-market to right-to-market and the product development paradigm has also evolved from procedure-focused to customer-needs-fulfillment-focused. How to develop the product that really meets customers’ wants and provides “tailor-made” features for individual needs is critical in contemporary product development. To avoid the product development behind schedule, over budget, possible runaway, or not the product customer wants, the design requirements are critical design information, which should always be available for easily accessing, retrieving, updating, changing, sharing and re-using in product development lifecycle since they drive and navigate the design activities and are used as the yardsticks or crietria to evaluate, verify and validate design solutions. To achieve this goal, the design requirements should be efficiently modeled and managed. In this paper, the modeling and management of design requirements are addressed. Foremost, the models of modeling and management processes are proposed and the detailed definitions are articulated. The issues in each process are presented and how to address them is proposed. From system point of view, a system framework is orchestrated and the components under the framework and their relationships are then delineated. A system information and process flow is presented and how to embed and package the developed technologies into a system is illustrated via the system information and process flow and GUIs.
A Parametric Study on the Infiltration of Fibrous Preform by Pure Al and Solidification Process in the Presence of Cooled Fibers
Authors: Lee E. K. , Amano R. S. , Rohatgi P. K.
Published: June 2008

Numerical simulation of the injection process of pure liquid aluminum into a fibrous preform has been carried out. During the injection process the end of the fibrous preform is allowed to be cooled by a heat sink. The purpose of cooling by a heat sink is to achieve a higher cooling rate, which is essential in obtaining finer microstructures and enhancing the growth of aluminum dendrites. The injection of liquid aluminum is modeled as flow in a porous medium and the heat equation coupled with the Darcy’s equation are simultaneously solved to obtain the temperature and velocity field. There are many different processing parameters influencing the solidification of aluminum. Among these parameters are, but are not limited to, the heat sink temperature, the thermal conductivity and initial temperature of the mold, and the length of fiber that is extending out of the mold. This article presents the simulation results of the effects of these processing parameters on the solidification of pure aluminum during the infiltration process.
Evaporative Heat Transfer Experiment of Air-Water Bubbly Flow
Authors: Chen Qinghua , Amano R. S. , Zhou Linli , Hou Yi
Published: June 2008

In this paper, a new kind of evaporative heat transfer experiment for the cooling process of coolers/condensers is conducted. The design of the test coils is immersed in an airwater bubbling layer. The air-water two-phase flow passes through the tubes of the coils. Due to the motion of the air bubbles in the water, a thin water film forms on the surface of the tube. As the air bubbles pass by the tube this water film is evaporated into the air. The tubes of coil reject heat to the water film, and the evaporation of the water film rejects heat to the air bubble stream. This heat transfer mode significantly increases the heat transfer coefficient between tubes and air. The consumption of the power of a water pump can be decreased. Moreover, the airflow rate required is less than that of an aircooled condenser. The pressure drop of air through air-water bubbling layer and the heat transfer between the tube and water are experimentally investigated in this paper. The results show that the factors affecting the pressure drop and the heat transfer coefficient involve the pore geometry of sieve plate, the height of the air-water bubbling layer, the air flow rate through the sieve plate and the heat flux of tubes. The heat transfer coefficient between tube and water is two times larger than that of falling film of water on the outer surface of tube.
An Evaluation of Simulated Flow and Experimental Study Through an Axial Fan
Authors: Xie J. , Amano R. S. , Lee E. K.
Published: June 2008

A comprehensive three-dimensional CFD approach and experimental study is developed for a 6-ft diameter commercial axial fan with rotational speed up to 1014 rpm. The use of sophisticated CFD software has made it possible to simulate fluid flow in complex moving geometries found in rotating machinery such as fans, pumps compressors, etc. In this paper, FLUENT is used to study an axial fan performance. Simulations are performed for steady state conditions using an implicitly rotating reference frame for the blades. Experimental studies are also conducted to visualize the flow on fan blade surface by using tuft method. The pressure and velocity distribution in front of the fan and the uncertainty dynamic pressure field measurement are also carried out. Comparisons between CFD simulation results and experimental measurement are found to be reasonable.
Energy Efficiency Analyses of Air-Conditioning Systems in Commercial Buildings in Egypt
Authors: Kameel Ramiz , Khalil Essam E.
Published: June 2008

Many buildings around the world utilize HVAC systems to provide the thermal comfort conditions for the occupants and users of these buildings as well as providing adequate conditions for special environmentally sensitive equipment. The appropriate air conditioning system design would necessarily provide the comfort and hygiene conditions with as low as possible initial capital and operating costs. The present study provides comprehensive analyses and comparisons between the water-cooled vs. air-cooled chillers with packaged water-cooled DX unit systems under the local Egyptian climatic conditions, primary water and energy prices and legistilations. The present study presents a comparison among the various systems according to the equipment and installation, operating, and maintenance costs. Based on the above analyses and the data collected with the prevailing prices, energy, water and maintenance costs at January 2003 in Egypt. It is apparent that water-cooled packaged units are of superior performance in terms of energy consumption and initial costs.
The Smart Car Project: Development and Implementation of a Modular Scaled Test-Bed
Authors: Jun Seung Kook , Krovi Venkat N.
Published: June 2008

In this paper, we investigate the development, implementation and testing of an inexpensive scaled-prototype “Smart Car Test-Bed”. The test-bed consists of retrofitting a commercially available radio-control (RC) truck with a PC/104 based computer with various embedded sensorand actuatorsubsystems together and multiple modes of communication (radio frequency (RF) and IEEE 802.11b wireless ethernet). The overall goal of our work is the creation of an inexpensive test-bed equipped with a real-time mediated control system to enhance the overall system autonomy and robustness. This test-bed enables us to study several concepts including: (i) mediation of human user control of complex robot systems; (ii) multi-user shared teleoperation; and (iii) robustness of the control in the presence of varying grades of communication — issues that are pertinent to a number of current and future generations of military/civilian systems.
RCS Based Hardware-in-the-Loop Embedded Control of Industrial Stamping Processes
Authors: Ananthakrishnan S. , Ananth Viswanath
Published: June 2008

There is a growing need for providing a flexible mechatronic environment to enhance productivity in industrial processes. Specifically, in the area of sheet metal forming, where stamping quality and part consistency are still achieved by traditional iterative process of trial and error, there is a clear urgency to enhance productivity and quality through automation. The traditional feedback control schemes used in many industrial processes cannot be applied to sheet metal forming, mainly due to the complexity of the stamping process and associated difficulty of using COTS (off-the-shelf) controllers for such applications. In this paper we demonstrate a hardware-in-the-loop flexible mechatronic design environment that will allow batch production of stamped parts with varying geometry and material properties, with minimal defects and greater consistency, using Simulink/RTW/xpcTarget framework which affords the feature of open architecture controller and the NIST Real-time Control System (RCS) architecture that allows structured, hierarchical implementation of industrial controllers. In conjunction with the Neutral Message Language (NML) RCS also allows for distributed hardware-in-the-loop control design with multiple processors. The merits of this approach over conventional approaches are also highlighted.
Graphics Tablet Embed Java-Applet and Web-Based Tele-Calligraphy of Pneumatic Manipulator
Authors: Hu Xudong , Wu Chuanyu , Yu Hong
Published: June 2008

Java becomes one of the most acceptable programming languages in the Intemet because of the characteristics of distribution, object-orientation, interpretation, and independence of computer platform. An application code programmed in Java can be downloaded and run in any client machine with Java VM through Internet. Most of internet-based application uses Java as the first choice of programming language. The Web-based Tele-calligraphy of pneumatic calligraphic manipulator described in here is one of these applications. In this article, authors will discuss the procedures of how to embed Unispen software package Wintab to Javaapplet using Java native interface (JNI). In the server machine, all communication functions between pneumatic servocontroller SPC-200 and computer had been compiled and linked to a dynamic loaded library in Ch language. Under the C/C++ superset interpreted language Ch, calligraphy handwrote by user in client machine will be formatted, sent, and calligraphed in a far located pneumatic robot manipulator through Internet.
Object-Based Interactive Control System Design and Analysis
Authors: Zhu Yong , Chen Bo , Cheng Harry H.
Published: June 2008

Ch is an embeddable C/C++ interpreter. It was developed to allow software developers to use one language, anywhere and everywhere, for any programming task. Ch supports C99, a latest C standard ratified in 1999, and contains salient features for two and three dimensional plotting and numerical computing for applications in engineering and science. Developed in Ch, Ch Control System Toolkit provides a control class with member functions for object-based interactive modeling, analysis, and design of control systems. The software package has been widely used in industry to solve practical engineering problems and in universities for instructional improvement. The design and implementation of Ch Control System Toolkit are described in this paper. An application example of control system design and analysis using Ch Control System Toolkit demonstrates its power and simplicity.
Development of a Web-Based Prototype for Real-Time Collaborative 3D Viewing
Authors: Chen Li , Liavas Billy , Song Zhijie
Published: June 2008

A collaborative 3D viewer is the recent technology that allows geographically distributed designers to view and markup the same CAD model without the need of a specific CAD system. However, most of the currently available collaborative 3D viewers only enable asynchronous collaboration among distributed designers. This paper targets the development of a Web-based real-time collaborative 3D viewer, named GlobalView, which is designed to support synchronous collaboration. In particular, the 3-tier client-server system architecture of GlobalView is illustrated and the implementation details are described according to its two main units: GlobalView Server and GlobalView Client. Finally, an application scenario of the usage of GlobalView is also illustrated. This 3D viewer will serve as one function module in our collaborative CAD system dedicated to collaborative assembly modeling.
Collaborative Engineering System Supporting Product Development Process
Authors: Park Hong-Seok , Lee Gyu-Bong , Kim Hyun
Published: June 2008

Since customer’s demand is various and product life cycle is getting shorter, many manufacturing company is trying to reduce product development time and cost. The processes of product development involve a large number of components and the interaction of multiple technologies. For the above reasons, companies make an effort to design product on collaborative environment. The various activities in a product development are highly distributed. This distributed nature of the activities implies that teams will be working in different place and technical environment. Thus at a given time, teams might work on the same product from different perspectives. This will require efficient communication amongst the various individuals and the various software tools that are used by them. Therefore, there is a need for collaborative system that can support distributed design such that participants from different background collaborate towards one common goal. IT (Information Technology) is the foundation for collaborative system. In this paper the development of an enterprise-specific collaboration-strategy including process oriented co-operations in product development will be presented. This strategy particularly comprises new customer-oriented functionalities, tools for supporting collaborative product development as well as a systematic support for an implementation of collaborative system.
Towards a Standardized Engineering Framework for Distributed, Collaborative Product Realization
Authors: Choi Hae-Jin , Panchal Jitesh H. , Allen Janet K. , Rosen David , Mistree Farrokh
Published: June 2008

In this paper, we propose a standardized computer-based engineering framework to support distributed product realization. The requirements for a standardized distributed product realization framework are developed based on the Open Engineering Systems paradigm. Existing computer frameworks are evaluated against the requirements and the missing features are identified. Our efforts towards development of such a framework — eXtensible Distributed Product Realization (X-DPR) environment are discussed. X-DPR is flexible and applicable to general industrial product realization processes. It is used to integrate distributed, collaborative product realization activities over the Internet. We trace the development of the framework based on design requirements. Features of X-DPR are implemented to satisfy each requirement. X-DPR is compared to existing engineering frameworks based on the required features. Limitations and future work are presented.
The Collaboration Abstraction Layer for Distributed CAD Development
Authors: Zhou H. , Lu Y. Q. , Li W. D. , Lin S. , Fuh J. Y. H. , Wong Y. S. , Qiu Z. M.
Published: June 2008

In order to speed up the development of distributed CAD (DCAD) software applications and offer the end-users a friendly environment for collaborative design, Collaboration Abstraction Layer (CAL) is proposed. CAL aims to develop a pluggable software module that can be embedded into standalone CAD applications. Through summarizing and abstracting out the common characteristics of distributed CAD software, a set of foundation/helper classes for the important collaborative functionalities are enclosed in CAL, which include a 3D streaming service, a collaborative design management service, a constraint checking/solving service and a file versioning/baseline service. The 3D streaming service incorporates a geometrical simplification algorithm that supports selective refinement on level of details (LOD) model and a compact data structure represented in an XML format. The collaborative management service effectively schedules and manages a co-design job. The constraint checking/solving service, which composes of a design task dispatch interface, a collision detection algorithm, and an assembly constraint algorithm, coordinates designing and assembling based on constraints. The CAD file versioning/baseline service is to manage the history record of the CAD files and the milestones in the collaborative development process. By simulating the real collaborative design process, CAL designs a new collaboration mechanism which is different from most collaboration products in market. For the future potential development, CAL is built on an open-sourced software toolkit. It is coded to interfaces and kernel libraries so as to provide an immutable API for commonly used collaborative CAD functions. CAL enables rapid development of DCAD software, and minimizes application complexity by packaging the needed technology. Moreover, CAL is intending to be a partner to the current CAD software, not competitor, making it an ideal tool for future distributed CAD system development.
Interactive Reduct Evolutional Computation for Aesthetic Design
Authors: Yanagisawa Hideyoshi , Fukuda Shuichi
Published: June 2008

We propose a method to evolve designs based on a user’s personal preferences. The method works through an interaction between the user and a computer system. The objective of the method is to help a customer set design parameters by simple evaluation of displayed samples. An important feature of this method is that the design attributes which a user pays more attention to (favored features) are estimated with Reduct in Rough Sets Theory and are reflected while refining the design. New design candidates are generated by the user’s evaluation of design samples generated at random. While values of attributes estimated as favored features are fixed in the refined samples, the others are generated at random. This interaction continues until the samples converge to a satisfactory design. Thus, this efficient design process evaluates a personal and subjective feature. This method is applied to design a 3D cylinder model such as a cup or a vase. This method is then compared with an Interactive GA.
Bone Surgery Simulation With Virtual Reality
Authors: Peng Xiaobo , Chi Xiaoyi , Ochoa Jorge A. , Leu Ming C.
Published: June 2008

Precise bone preparation is a key element for the successful long-term fixation of orthopaedic implants. Initial stability leading to reduced micromotion and direct apposition of the bone against the implant are mainly responsible for proper load transfer and bone remodeling. The fit and fill of the implant is created by shaping and sizing a cavity within the bone to accommodate the implant, which is usually accomplished by standard machining operations such as broaching, milling and drilling. This paper presents our initial study of developing a bone drilling simulation system, with the goal of guiding a novice surgeon to practice the bone drilling operation. A virtual reality approach is taken to provide force feedback, in order to make the simulation system more intuitive and interactive. Octree is used to organize and manipulate the volumetric data representing the bone model. Adaptive surface rendering is chosen as the graphics display algorithm. Multithreading is used to address the different update rates required in the real-time graphic and haptic displays.
Numerical Modeling of Flexible Components for Assembly Path Planning Using a Virtual Reality Environment
Authors: Mikchevitch A. , Le´on J.-C. , Gouskov A.
Published: June 2008

The aspects of adequate simulation of the flexible parts for path planning during the Assembly/Disassembly (A/D) operation simulation are discussed in this paper. An interactive system forming two complementary levels and incorporating mechanical models of flexible part is described. The approach proposed will be used as a basis to the simulation of flexible parts into a Virtual Reality (VR) environment for the A/D evaluation. First of all, the study of current assembly path planning systems is performed. Secondly, as an issue of the problems discussed, a new system integrating real-time and interactive mechanical simulation approaches is proposed. Finally, an example of the interactive mechanical behavior model applicable to flexible rods used into an A/D path planning context is presented. Numerical modeling focuses on typical boundary conditions. The present approach is considered as a proposal for a methodology used with VR environments during the product design process.
CAD Model Assembly Hierarchy Reorganization for Application in Virtual Assembly: A Hybrid Approach Using the CAD System and a Visualization Tool
Authors: Kim YoungJun , Jayaram Uma , Jayaram Sankar , Jandhyala Venkata K. , Mitsui Tatsuki
Published: June 2008

The hierarchy of assembly components in a CAD assembly model is rarely a true representation of the sequence of assembly of these components during manufacturing. Thus, any assembly planning or evaluation software system needs to re-order and re-group the various components of the CAD assembly model to reflect the sequence of component assembly. Although all parametric CAD systems allow reorganization of the assembly tree, it is a difficult and timeconsuming process due to the relationships and constraints between the various components. We propose an alternative hybrid method that couples the CAD system and a visualization tool that supports reorganization, while preserving data, to allow fast and easy rearranging of the assembly hierarchy. Also, after the reorganization, polygonal representations of the new sub-assemblies are created and the original constraints are also transformed in a consistent manner. As a next logical step, we compare the time required to rearrange the assembly hierarchy using both methods — the CAD system alone and the hybrid system. A statistical analysis using three treatment factors indicates that if the number of components is more than 15, then it is more efficient to use the hybrid method over the CAD system. The overarching goal was to allow fast and efficient creation of different assembly hierarchies to allow the corresponding assembly sequences to be verified in a virtual assembly application that derives its models and constraints from the assembly hierarchy in the CAD system. We have implemented the method to allow the successful reorganization and virtual assembly verification of many industry models, some with several hundred components, provided by various industry partners.
A Cross-Evaluation Matrix (CEM) Rating Based Approach to Pareto Efficient Frontier and Design Alternatives Enumeration
Authors: Krishnamurthy Anand , Krishnamurthy Sundar
Published: June 2008

This paper introduces a novel cross-evaluation matrix (CEM) rating based approach for the development of Pareto efficient frontiers and the finding of discrete sets of globally non-inferior design sets. This work, based on concepts from data envelopment analysis (DEA), can facilitate the enumeration of design candidates in a multi-criteria formulation. In addition, it is expected that the resulting design sets will provide the basis for the establishment of a value system and subsequent preference based rank ordering of expected outcomes in the single-criterion formulation. A unique feature of this cross-evaluation matrix approach is its ability to handle problems without requiring a priori tradeoff formulation or multiattribute model development. As such, its application does not require assignment of a set of a priori weight constants as in many well-established Pareto-optimal generating methods, nor does it need any a priori information of the global minimum or maximum of the attribute functions. Recognizing that the enumeration of multiple discrete solution alternatives can be best achieved in a parallel computation environment, the implementation in this work is executed with the aid of a genetic algorithm strategy. The effectiveness of the integrated approach in yielding Pareto-optimal candidate design sets under different scenarios are studied in the context of illustrative examples, including two engineering case studies, and the results are discussed.
An Indicator Response Surface-Based Monte Carlo Method for Efficient Component and System Reliability Analysis
Authors: Zou Tong , Mourelatos Zissimos P. , Mahadevan Sankaran , Tu Jian
Published: June 2008

Reliability analysis methods are commonly used in engineering design, in order to meet reliability and quality measures. An accurate and efficient computational method is presented for reliability analysis of engineering systems at both the component and system levels. The method can easily handle implicit, highly nonlinear limit-state functions, with correlated or non-correlated random variables, which are described by any probabilistic distribution. It is based on a constructed response surface of an indicator function, which determines the “failure” and “safe” regions, according to the performance function. A Monte Carlo simulation (MCS) calculates the probability of failure based on a response surface of the indicator function, instead of the computationally expensive limit-state function. The Cross-Validated Moving Least Squares (CVMLS) method is used to construct the response surface of the indicator function, based on an Optimum Symmetric Latin Hypercube (OSLH) sampling technique. A number of numerical examples highlight the superior accuracy and efficiency of the proposed method over commonly used reliability methods.
Structural Durability Design Optimization and Its Reliability Assessment
Authors: Choi Kyung K. , Youn Byeng D. , Tang Jun
Published: June 2008

Mechanical fatigue subject to external and inertia transient loads in the service life of mechanical systems often leads a structural failure due to accumulated damage. Structural durability analysis that predicts the fatigue life of mechanical components subject to dynamic stresses and strains is a compute intensive multidisciplinary simulation process, since it requires an integration of several computer-aided engineering tools and large amount of data communication and computation. Uncertainties in geometric dimensions due to manufacturing tolerances cause the indeterministic nature of fatigue life of the mechanical component. Due to the fact that uncertainty propagation to structural fatigue under transient dynamic loading is not only numerically complicate but also extremely expensive, it is a challenging task to develop structural durability-based design optimization process and reliability analysis to ascertain whether the optimal design is reliable. The objective of this paper is development of an integrated CAD-based computer-aided engineering process to effectively carry out the design optimization for a structural durability, yielding a durable and cost-effectively manufacturable product. In addition, a reliability analysis is executed to assess the reliability for the deterministic optimal design.
Incorporating Epistemic Uncertainty in Robust Design
Authors: Dai Zhihuang , Scott Michael J. , Mourelatos Zissimos P.
Published: June 2008

There are two sorts of uncertainty inherent in engineering design, random uncertainty and epistemic uncertainty. Random, or stochastic, uncertainty deals with the randomness or predictability of an event. It is well understood, easily modelled using classical probability, and ideal for such uncertainties as variations in manufacturing processes or material properties. Epistemic uncertainty deals with our lack of knowledge, our lack of information, and our own and others’ subjectivity concerning design parameters. While there are many methods to incorporate random uncertainty in a design process, there are fewer that consider epistemic uncertainty. There are fewer still that attempt to incorporate both sorts of uncertainty, and those that do usually attempt to model both sorts using the same uncertainty model. Two methods, a range method and a fuzzy sets approach, are proposed to achieve designs that are robust to both epistemic uncertainty and random uncertainty. Both methods incorporate preference aggregation methods to achieve more appropriate trade-offs between performance and variability when considering both sorts of uncertainty. The proposed models for epistemic uncertainty are combined with existing models for stochastic uncertainty in a two-step process. An illustrative example incorporating subjectivity concerning design parameters is presented.
WirePATH Rapid Tooling Process and Supporting Software Development
Authors: Lee Alexander , Brink James , Anderson David , Ramani Karthik
Published: June 2008

Recent developments in Computer Aided Design (CAD) have drastically reduced overall design cycle time and cost. In this paper, wirePATH, a new method for rapid direct tooling, is presented. By using specialized interactive segmentation computer software and wire electrical discharge machining (wire EDM), wirePATH can reduce manufacturing time and cost for injection molds, casting patterns, and dies. Compared to other conventional-mold making methods, wirePATH can reduce fabrication time by as much as 40 to 70%. Wirepath can use a combination of wire EDM and other processes. Our method provides a new means to produce a greater variety in products by changing only portions of the tooling. Segments allow a part of a mold to be replaced to accommodate design changes and repair. WirePATH enables new applications of wire EDM to more complex shapes by bridging the gaps between CAD, our method, wire EDM and conventional manufacturing processes.
Structural Topology Design Optimization for Controlled Crash Behavior
Authors: Soto Ciro A.
Published: June 2008

This paper presents a methodology to perform structural topology design optimization for crashworthiness considering a prescribed and safe structural behavior through the dynamic equilibrium equation. This implementation, called here controlled crash behavior, or CCB, is very useful for design engineers in the automotive industry since it allows them to ‘prescribe’ a structural behavior of the vehicle at given locations of interest. The methodology is based on previous work from the author where the optimum topology is determined using a heuristic (optimality) criterion to attain a design with prescribed levels of plastic strains and stresses. The paper includes a simple beam example to demonstrate the CCB approach. Results are consistent with the formulation of the optimization problem.
Knowledge Management: A Concept Review
Authors: Mekhilef Mounib , Deshayes Philippe
Published: June 2008

The reality of the Knowledge Management (KM) joins in a multiplicity of ends and situations. In the scientific literature, KM seems to appear as a sort of more or less unified and more or less generative “field of research” of specialists’ community. Nevertheless, a detailed analysis of the scientific production relative to the Knowledge Management shows essentially that the management of knowledge and competence became a preoccupation in a big part of sciences and techniques. This is translated by a big number of actors (university, consultant, industrial, etc.) constituting a community of preoccupations. It deals also with a profusion of publications, various networks and a rising offer of specialized trainings. However, the big variety of points of view and interpretations which join to the knowledge and competence management calls up to a lot of caution as for any other scientific discipline, and invites to understand the senses which are given to them. Indeed, no fundamental scientific result appeared really: literature supplies only approaches which hold more feeling than it is important, or very pragmatic applications, sending back mostly to particular cases of companies.
A Knowledge-Supported System for Engineering Change Impact Analysis
Authors: Ma Sha , Song Bin , Lu Wen Feng , Zhu Cheng Feng
Published: June 2008

Engineering changes are inevitable in a product development life cycle. The requests for engineering changes can be due to new customer requirements, emergence of new technology, market feedback, or variations of components and raw materials. Each change generates a level of impact on costs, time to market, tasks and schedules of related processes, and product components. Change management tools available today focus on the management of document and process changes. Assessments of change impact are typically based on the “rule of thumb”. Our research has developed a methodology and related techniques to quantify and analyze the impact of engineering changes to enable faster and more accurate decision-making in engineering change management. Reported in this paper are investigations of industrial requirements and fundamental issues of change impact analysis as well as related research and techniques. A framework for a knowledge-supported change impact analysis system is proposed. Three critical issues of system implementation, namely integrated design information model, change plan generator and impact estimation algorithms, are addressed. Finally the benefits and future work are discussed.
Parametric Design Sensitivity Analysis of High Frequency Structural-Acoustic Problems Using Energy Finite Element Method
Authors: Choi Kyung K. , Dong Jun , Vlahopoulos Nickolas , Wang Aimin , Zhang Weiguo
Published: June 2008

A design sensitivity analysis of high frequency structural-acoustic problem is formulated and presented. The Energy Finite Element Method (EFEM) is used to predict the structural-acoustic responses in high frequency range, where the coupling between the structural and acoustic domain are modeled by using radiation efficiency. The continuum design sensitivity formulation is derived from the governing equation of EFEM and the discrete method is applied in the variation of the structural-acoustic coupling matrix. The direct differentiation and adjoint variable method are both developed for the sensitivity analysis, where the difficulty of the adjoint variable method is overcome by solving a transposed system equation. Parametric design variables such as panel thickness and material damping are considered for sensitivity analysis, and the numerical sensitivity results show excellent agreement comparing with the finite difference results.
Computer Model Validation in Vehicle Crash Safety Design
Authors: Gu Lei , Yang R. J.
Published: June 2008

This paper describes the framework of nonlinear finite element model validation for vehicle crash simulation. Several methods were developed to quantify transient time-domain data (functional data). The concept of correlation index was proposed to determine the degree to which a model is an accurate representation of the real world from the perspective of the intended uses of the model. The methodologies developed in this paper can also be used for CAE model updating, parameter tuning, and model calibration.
A New Global Optimization Method for Simultaneous Computation on Expensive Black-Box Functions
Authors: Wang Liqun , Shan Songqing , Wang G. Gary
Published: June 2008

The presence of black-box functions in engineering design, which are usually computation-intensive, demands efficient global optimization methods. This work proposes a new global optimization method for black-box functions. The global optimization method is based on a novel mode-pursuing sampling (MPS) method which systematically generates more sample points in the neighborhood of the function mode while statistically covers the entire search space. Quadratic regression is performed to detect the region containing the global optimum. The sampling and detection process iterates until the global optimum is obtained. Through intensive testing, this method is found to be effective, efficient, robust, and applicable to both continuous and discontinuous functions. It supports simultaneous computation and applies to both unconstrained and constrained optimization problems. Because it does not call any existing global optimization tool, it can be used as a standalone global optimization method for inexpensive problems as well. Limitation of the method is also identified and discussed.
Multidimensional Solution Clustering and Its Application to the Coolant Passage Optimization of a Turbine Blade
Authors: Jeong Min Joong , Dennis Brian H. , Yoshimura Shinobu
Published: June 2008

Data clustering methods can be a useful tool for engineering design that is based on numerical optimization. The clustering method is an effective way of producing representative designs, or clusters, from a large set of potential designs. These methods have recently been applied to the clustering of Pareto-optimal solutions from multi-objective optimization. The results presented here focus on the application of clustering to single objective optimization results. In the case of single objective optimization, the method is used to determine the clusters in a set of quasi-optimal feasible solutions generated by an optimizer. A data clustering procedure based on an evolutionary method is briefly described. The number of clusters is determined automatically and need not be known a priori. The method is demonstrated by application to the results of a turbine blade coolant passage shape optimization problem. The solutions are transformed to a lower-dimensional space for better understanding of their variance and character. Engineering information, such as the shapes and locations of the internal passages, is supported by the visualization of clustered solutions. The clustering, transformation, and visualization methods presented in this study might be applicable to the increasing interpretation demands of design optimization.