bluuebunny/crossref_metadata_2025 huggingface dataset:
Numerical Solution of Multiphysics Large Deflection Plates for Ionic Polymeric Artificial Muscle Applications
Authors: Michopoulos J. G.
Published: June 2008

Recent advances in the manufacturing of new materials that can by activated by multifield excitation have introduced the need for modeling their multiphysics behavior. In responding to this need the special case of electric multihygrothermoelasticity is being considered as the closest multiphysics theory for modeling the behavior electro-hygrothermo-elasto-active materials utilized in artificial muscle applications. Furthermore, the system of governing partial differential equations describing the state evolution of large deflection plates made from such materials is derived as a twodimensional specialization of the above mentioned theory. These electro-hygro-thermally modified Von-Karman nonlinear equations are solved numerically through an adaptive finite element approach and preliminary results are presented for the case of a rectangular ionic polymeric material plate under various boundary conditions. Finally, various issues associated with the regimes of applicability of this theory and approach are also presented.
Shell or Plate Idealization on a Polyhedral Model for Finite Element Analyses
Authors: Drieux G. , Le´on J.-C. , Fine L.
Published: June 2008

Very often, geometric transformations are required to adapt the geometry of a component to the requirements and hypotheses of a structural model in order to generate a Finite Element (FE) mesh suitable for modeling some physical phenomenon. This co-called idealization process is usually time consuming. This paper introduces a new set of operators to perform this preparation phase. The operators proposed are based on a polyhedral representation of the component to enable structural analyses to be integrated at various stages of the design process without requiring a model issued from a CAD system. The operators fit into an approach where geometrical criteria and mechanical ones are distinguished. Here, a first set of geometric operators is described and mechanical criteria are highlighted to set their relative positions. Two distinct stages are set up in applying geometric operators: firstly, candidate areas reflecting plate or shell morphology are identified and transformed into open surfaces ; secondly, the connections between the shell or plate elements are addressed through mechanical and geometrical criteria to allow the analyst to express the hypotheses he (resp. she) requires. Across these stages, the continuity and integrity of the model is always preserved, which enables a wide variety of treatment of the connections between the plate or shell elements, as it is often required when modeling structures. Finally, examples are provided to illustrate the efficiency and the potential of the approach proposed.
An Information-Driven FEA Model Generation Approach for Chip Package Applications
Authors: Zeng Sai , Peak Russell , Matsuki Ryuichi , Xiao Angran , Wilson Miyako , Fulton Robert E.
Published: June 2008

In the electronic chip package development process, Finite Element Analysis (FEA) modeling is widely used as a virtual prototyping technology to achieve good designs. Due to the complexity and variability in materials, geometric shapes, and connectivity configurations, etc. in a chip package, FEA modeling is a tedious and time-consuming activity. Typically finite element modeling takes hours or even days to complete an analysis for a single chip package design. The Multirepresentation Architecture (MRA) is presented as a framework to facilitate automatic transformations of design models into analysis models through four stepping-stone information representations: (1) analyzable product models (APM), (2) context-based analysis models (CBAM), (3) analysis building blocks (ABBs), and (4) solution method models (SMMs). The ABB models describe theoretical physical systems while SMMs represent the ABB models in solution technique-specific form, such as FEA. In this paper, we present an information-driven FEA modeling approach facilitating the mapping between ABBs and SMMs by first decomposing the geometry into meshable bodies and subsequently generating vendor-specific SMMs. To demonstrate this FEA modeling approach, a chip package thermomechanical analysis example is given. The informationdriven FEA modeling approach is shown to be an effective and efficient method for capturing engineering information in chip package products, as well as decreasing FEA modeling time.
Finite Element Analysis of Effect of Planar Anisotropy on Springback in Plane Strain Bending
Authors: Raju D. V. , Ravi Kumar D.
Published: June 2008

In this paper, springback has been determined experimentally in plane strain sheet bending for a sheet with high planar anisotropy at different orientations to the rolling direction. Springback was predicted by analysis of plane strain bending using the Finite Element Method (FEM). The mechanical properties of sheet metal (at different angles to rolling direction) and anisotropic parameters were determined from uniaxial tension tests and were used as the input for FEM analysis. Analytical calculations were also carried out to predict springback at different orientations. Comparison of the results showed that FEM predictions are closer to experimental results than the analytical calculations. The present work is expected to provide more insight into understanding of the effect of anisotropy on springback in sheet bending operations and provide information which can be useful for manufacturers of sheet metal components (involving bending) to choose the optimum orientation of bend axis so as to get the desired quality after forming.
Improving Spot Weld Models in Structural Dynamics
Authors: Palmonella Matteo , Friswell Michael I. , Mares Cristinel , Mottershead John E.
Published: June 2008

This paper gives an overview of the finite element modelling of spot welds for the analysis of the dynamic response of structures. In particular models for dynamic analysis that use coarse meshes and equivalent parameters are considered. A major requirement for these models is their accuracy in predicting the dynamic behaviour of spot welded structures despite the low number of degrees of freedom. Three different models of spot welds are investigated [1–3] and for each model physical parameters have to be assigned based on engineering insight. The aim of the present paper is to improve the accuracy of these three models by searching for the optimum values of the parameters characterising the spot weld models using experimental data. For this purpose a benchmark structure has been analysed, consisting of a thin walled hat section beam made of two plates welded together by twenty spot welds. The predicted natural frequencies and modes of the benchmark structure have been compared to the experimental modes. Updating of the finite element models has been performed and the accuracy of the three models has been significantly improved.
Knowledge Management System for Problem Solving: Integration of Document Information and Formalized Knowledge
Authors: Yoshioka Masaharu , Shamoto Yasuhiro
Published: June 2008

In engineering activities various types of problems have to be solved. Most of these problems are routine problems and some are complicated problems for which it is difficult to formalize all the problem-solving processes. We propose a knowledge management system for supporting these problem solving processes. One example is using information applicable to new and complicated problems that has resulted from solving similar problems in the past. In addition, in such complicated problem solving processes, most of the decomposed sub-problems can be handled as routine problems. In this paper, we propose use of formalized knowledge and document information that represents the history of problem-solving processes to support the solution of both types of problem. For that purpose, we propose the Documentation Management system for Problem Solving (DMaPS), which supports a user solving a problem by document processing. In this support process, the system retrieves related documents for the user’s problems using formalized knowledge and information retrieval techniques. After retrieving related documents, the user modifies them to fit their problem. The modified information is associated with the formalized knowledge and is stored as documents for future reuse.
Requirement-Driven Design Processes With Integrated Knowledge Structures
Authors: Sunnersjo¨ Staffan , Rask Ingvar , Amen Rafael
Published: June 2008

Customer requirements provide objectives and constraints for all phases of the product development process. For complex system products with a high degree of customization, it is no mean task to ensure that the right persons at the right time have ready access to the selected requirement specifications that they should adhere to and strive to satisfy. In the present work a systematic sequence of development phases associated with computer implemented information structures for requirements, functions and systems have been studied at three companies with widely different products and business scenarios. Although individual adaptations are required, the overall processes for requirement decomposition and propagation appear surprisingly similar. To fully exploit the potential of such information systems, many companies would benefit from also including knowledge structures in their product models. Fundamental product and process knowledge often evolves slowly over time, can be gradually upgraded and be reused many times. It also constitutes one of the company’s most valuable assets and should be carefully maintained and enhanced. In the work presented here a few different approaches to integrating knowledge structures into the total product information structure have been developed and exemplified for the three companies studied.
Experiences in Designing Highly Adaptable Expertise Finder Systems
Authors: Hughes Gareth , Crowder Richard
Published: June 2008

A strategy or method for identifying an expert is at the core of any Expertise Finder system. The strategy used must reflect the social requirements of the organisation and its assets, culture and technology. An Expertise Finder strategy must attempt to emulate the steps a member of that organisation would do to find the answer to their questions. Our collaboration with a large manufacturing enterprise has helped us evolve an approach to building Expertise Finder systems. Our approach contains the required flexibility to cope with the mix of technological, social and legacy factors that make each deployment of an Expertise Finder system very different to any other. The component based design allows a deployer to customise the basic system to utilise their relevant technical resources and then to build a unique strategy algorithm to produce a valid set of recommendations. The design produces challenging questions of how to produce a procedure for designing, deploying and evaluating the Expertise Finder strategy. This paper discusses the evolution of this design strategy and summarises our experiences to date.
Information Modeling for Integrated Product Design, Process Planning and System Design for Powertrain Machining
Authors: Li Jianming , Subramanian Samba , Swisher Steve , Yip-Hoi Derek
Published: June 2008

To shorten product development lifecycles for machined powertrain components, it is necessary to develop technologies around integrated product design, process planning and system design. This integration should enable information once created to be readily available across all activities of the lifecycle. A key to achieving this is the creation of an information model for capturing and relating this information. This model should be comprehensive and easily navigable to enable, for instance, manufacturing engineers to trace tasks on the stations in a machining line to specific surfaces on in-process states of the workpiece. Also of importance are strategies that specify how instances of this model are created and how it is to be maintained. This paper presents information models created specifically for powertrain machining. These models have been implemented as a database within a framework for integrated product design, process planning and system design. An XML (eXtensible Markup Language) application based on the model has also been developed to standardize interfaces and facilitate communication within product development teams and with suppliers.
ppXML: Towards Generic and Extensible Modelling of Platform Products
Authors: Huang G. Q. , Bin S. , Mak K. L.
Published: June 2008

ppXML is an information infrastructure that enables and facilitates meaningful information and knowledge management within and interoperability between web services (applications) for Platform Product Development (PPD) — a formidable approach to agile product development (APD) for mass customization (MC). There are four folds of meanings in ppXML. Firstly, ppXML represents a set of constructs that are consistent with concepts and methods of Platform Product Development for Mass Customization. Secondly, derived from XML (eXtensible Markup Language) as a sublanguage, ppXML is a standard and yet extensible modeling language dedicated to the modelling of products and product platforms for PPD web services. Thirdly, ppXML serves as a product platform repository and a PPD web service registry, together with a set of online facilities for data representation and transformation between different components and parties involved in the web services. Finally, ppXML is a proof-of-theconcept online PPD portal, incorporating some essential web-based Decision Support Systems (DSS) for product platform development and product platform customization. This paper presents an overview of ppXML together with its background and underlying philosophy.
An Agent Based Framework to Automatically Generate 3D CAD Models of Customer Specified Products
Authors: Siddique Zahed , Boddu Karunakar Reddy
Published: June 2008

To survive in today’s volatile market, companies are striving to deliver greater quality, more customization, faster response, more innovative designs and lower prices. The new shift in the current market has introduced the concept of mass customization. One of the aspects of mass customization is to provide customers with products that are manufactured to their needs and requirements. To provide such a support requires better integration of customer with different stages of design and manufacturing. Expansion of the Internet provides an opportunity for such an integration, which will need to link design and manufacturing of the company with the customer. In current approaches, customer usually specifies the options and gets the price or simple pictures of the object. In this paper a system is presented, where customer options and size parameters are gathered using the Internet and is used to automatically generate 3D CAD model of the product and then display the 3D model to the customer for feedback. Development of a framework to generate 3D models from user input will require maintaining explicit correspondence among various types of product information from a module perspective. The Internet based system presented in this paper uses templates to automatically generate 3D CAD models of components, assemble them into products and then export VRML files that are displayed to the customer.
XML-Based Integration of Design, Analysis and Manufacturing
Authors: Wang Lidong , Ting Kwun-Lon , Kosa Martha
Published: June 2008

The integration of design, analysis and manufacturing is a challenging issue in product development. Much research focuses on creating data exchange standards such as STL, IGES, EDI, and STEP etc. However, these standards are not ideal in data exchange and communication via the Web. In this paper, a unified framework based on XML was created to integrate design, analysis, and manufacturing. The structures of DTDs and XML files of geometric design, finite element analysis and NC machining were developed. Key technologies of supporting the XML-based integration and information communication, such as DOM, SAX and SOAP etc. were discussed. XML-based integration will shorten the development cycle, save costs in product development, and finally improve the competitive capability in the global competition of product development.
Extensible Semantics for Representing Electromechanical Assemblies
Authors: Kopena Joseph , Regli William C.
Published: June 2008

Many representations exist for describing engineering artifacts. These representations come from a wide variety of work in many research areas with differing backgrounds and purposes. No unified representation has emerged combining aspects of existing schemes with an ability to easily grow and be extended over time. In this work we demonstrate the application of methods from the knowledge representation community to the domain of engineering artifacts, in particular electromechanical assemblies. We use conceptual graphs as a formal, cleanly extensible representation form. Aspects of several existing results are combined to create a unified representation and demonstrate the approach. We also discuss translation of the conceptual graphs to the DARPA Agent Markup Language (DAML) in order to utilize and cooperate with efforts to develop ontologies for this domain.
ERMM: An Engineering Requirements Management Method
Authors: Becker Beverly , Wang Nanxin
Published: June 2008

Automotive product development is a lengthy and complex process. There exists a large body of various requirements, standards, and regulations, which need to be followed by all engineering activities throughout the entire vehicle development process. The underlying relationships between these requirements are very complicated. Although most of engineering requirements can be found in various engineering databases, it is the lack of the underlying relationship between the requirements and their association with the design that makes it extremely difficult for even experienced engineers to follow the requirements in their dayto-day work. This paper introduces an Engineering Requirements Management Method (ERMM) that captures these interrelationships and associations using a matrix-based representation. A case study with a real automotive component is also presented.
Enhancing Virtual Product Representations for Advanced Design Repository Systems
Authors: Bohm Matt R. , Stone Robert B. , Szykman Simon
Published: June 2008

This paper describes the transformation of an existing set of heterogeneous product knowledge into a coherent design repository that supports product information archival, storage and reuse. Existing product information was analyzed and compared against desired outputs to ascertain what information management structure was needed to produce design resources pertinent to the design process. Several test products were cataloged to determine what information was essential without being redundant in representation. This set allowed for the creation of a novel single application point of entry for product information that maintains data consistency and allows information be easily exported. The exported information takes on many forms that are valuable to the design process such as a bill of materials and component function matrix. Enabling technologies include commercial software, XML (eXtensible Markup Language) data, XSL (eXtensible Stylesheet Language) transformation sheets and HTML (HyperText Markup Language). Through this process researchers at the University of Missouri – Rolla (UMR) have been able to dramatically improve the way in which artifact data is gathered, recorded and used.
Knowledge-Based Concurrent Product Development Process Management System and Its Implementation
Authors: Zhong Peisi , Zeng Qingliang , Liu Mei , Liu Dazhi
Published: June 2008

Concurrent engineering is a systematic approach to integrate concurrent design and its related processes. Its objective is to shorten the product development cycle, improve the product quality and reduce the product cost. Product development process management is one of the key enabled technologies for the implementation of concurrent engineering. The main purpose of the study on knowledge-based concurrent product development process management is to explore the theory and methods on process modeling, monitoring, analysis, reengineering and so on, and to integrate the knowledge processing into the lifecycle of the product development including mainly the acquisition and usage of design history and domain knowledge. Modeling the product development process is the first step of product development process management. A method for the knowledge-based multi-view process modeling is present. The rule-based mechanism for process implementation is discussed. The method for acquisition of design history and domain knowledge is presented. The multi-agent based architecture of knowledgebased concurrent product development process management system is developed and used successfully during the life cycle of a new type of railway rolling stock development in a Chinese enterprise, QQHR Railway Rolling Stock Company.
Systematic Design Method for Information Modeling in CAD/CAE
Authors: Zeng Sai , Kim Edward J. , Mocko Gregory M. , Xiao Angran , Peak Russell , Mistree Farrokh
Published: June 2008

As engineering systems are increasingly becoming more complex, the need for information models is growing accordingly. Extensive research is currently underway to develop engineering data management capabilities and to understand the role of information as a systems integrator. In order to develop information models more effectively, a systematic methodology is needed to better manage data and develop information models. In the area of CAD/CAE/CAM applications, an information gap exists between design models and analysis models. To this end, a multi-representational architecture (MRA) is presented to facilitate the transformation of information from design models to various support analysis models. In this paper, our primary focus is on ABBs (Analysis Building Blocks) for solid mechanics and thermal systems that generate FEA (Finite Element Analysis) SMMs (Solution Method Models) to obtain their results. Our focus in this paper is to investigate the effectiveness of the Pahl and Beitz methodology in developing the ABB information model. The Pahl and Beitz design methodology is intended for physical product design applications. Three of the four phases of the Pahl and Beitz methodology are examined and modified to facilitate development of the ABB information model. The augmentations of these phases are presented in this paper. The results of the development of concepts of ABB information model using the Pahl and Beitz methodology support the use of systematic design methodologies for the development of information models. The emphasis of this work is on the methodology used to develop the ABB information model rather than the technical result of the ABB model.
Utility Integration of WECS Technologies: Relevant Issues and Major Concerns
Authors: Sharaf-Eldeen Y. I. , Sullivan R. L.
Published: June 2008

A comprehensive review of major publications on WECS-utility integration studies has been carried out. Outlines of various modeling and simulation methods used for including WECS plants into the generation mix of electric utility systems are presented. Issues and concerns of the utility industry relevant to the integration of WECS, including planning, cost, operations, reliability, dynamic interactions, etc. are also outlined.
Non-Heating Sterilization Method by High Pressure Carbon Dioxide
Authors: Lee S. , Chen Q. , Amano R. S.
Published: June 2008

The compressed CO2 was supplied from the CO2 cylinder to the steel vessel containing yeast-water mixture until the pressure inside the steel vessel reached a desired pressure level. The steel vessel was kept at the prescribed pressure level during the treatment period. After the treatment, the pressure inside the vessel was released to the atmospheric pressure within the evacuation time by controlling the relief control valve. The sterilization effect was evaluated by vial counting the treated sample taken from the steel vessel. Several experiments have been performed varying each factor such as the total treatment time, the evacuation time and the applied pressure. As a result, it was verified that these factors are strongly related to the sterilization effect. In addition, it was observed that increase of the treatment time can enhance the concentration rate of CO2 in the mixture. Furthermore, it was concluded that CO2 penetrated into each yeast cell was rapidly expanded by fast depressurizing. Also, the experimental results showed that when treatment time is longer, the pressure becomes higher, and the evacuation time is shorter, thus, a better sterilizing effect was obtained. Contrary to the results above, both the treatment time and the evacuation time rarely affected sterilization effect under supercritical condition. By adopting Supercritical condition, a desirable result could be achieved with shorter treatment and longer evacuation time. Thus, as long as supercritical condition is adopted for test, either fast evacuation time or long treatment time is not essential any more.
A Web-Based Product Structure Manager to Support Collaborative Assembly Modeling
Authors: Chen Li , Wang Tingjin , Song Zhijie
Published: June 2008

Collaborative CAD systems enabling collaboration in CAD among distributed designers are gaining more and more attention. Yet, such systems, especially in support of collaborative assembly modeling, are hardly achievable. In an effort to bridge this gap, we are dedicated to developing a collaborative CAD system with aim at 3D assembly modeling. As part of this effort, this paper addresses one function module of the system, a Web-based Product Structure Manager, that enables Collaborative Product Structure Management (CPSM) in collaborative assembly modeling. In particular, CPSM facilitates product data sharing among distributed designers and supports collaboration in product structure creation and modification. A bench clamp assembly is used as an example for the illustration of the Product Structure Manager in support of collaborative assembly modeling.
Distributed Management, Monitoring and Control of Manufacturing Shop Floors
Authors: Shen Weiming , Wang Lihui , Lang Sherman , Wong Brian , Hao Qi
Published: June 2008

This paper presents some results of our research on distributed management, monitoring and control of manufacturing shop floors using the Internet, Web and agent technologies. Two new concepts are proposed and developed: iShopFloor on the application of Distributed Artificial Intelligence to the shop floor for distributed intelligent manufacturing process planning, scheduling, sensing and control; eShopFloor on the development of a Web based collaborative environment for remote monitoring, control, diagnostics and maintenance of manufacturing devices (e.g., machines, robots) in the shop floor. Prototype implementation details are presented and key implementation issues are discussed.
Integrating Producibility and Product Performance Tools Within a Web-Service Environment
Authors: Beiter Kurt A. , Ishii Kosuke
Published: June 2008

This paper describes the integration of a producibility and product performance tool in a web service environment. First, we provide a background on web services and a review of product development environments that utilize a service-based architecture. Next, the paper describes the implementation of two services—a process capability database coupled with an aircraft engine fuel nozzle performance model. Discussions close addressing the challenges faced in the current software services development environment.
Exploration of Evolutionary Path Planning of Part Handling in Sheet Metal Bending
Authors: Liao Xiaoyun , Wang G. Gary
Published: June 2008

While the bending sequence planning has been intensively studied, design of the motion path of a sheet metal part in the bending operation tends to be ignored by researchers. Because during the bending operation, the space for maneuvering a sheet metal part is very small, collisions between the part and bending tools are likely to occur. When a robot is used to handle the part, the role of an automatic path-planning tool becomes more significant. In this study, an evolutionary pathplanning approach for robot-assisted handling of sheet metal parts in bending is proposed and implemented. The proposed approach globally searches the motion path space to identify feasible paths. Collision detection algorithms based on segment intersection are used to check the feasibility of the generated paths. This method can automatically design feasible handling operations for a robot. A simulation example on a simple “V” shaped part demonstrates that the approach is efficient and practical.
A Systematic Approach for Developing Nonlinear Control Systems With Fuzzy Logic
Authors: Edwards Dean B. , Feeley Joseph J. , Okamoto Akira
Published: June 2008

In this paper we present a method for systematically developing nonlinear control systems that provide superior performance to conventional linear control systems. The approach uses the results of linear analysis as a starting point for designing and optimizing a nonlinear control system. A linear equivalent fuzzy logic control system is constructed to give the same performance as the “best” linear control system. The fuzzy logic control system is subsequently modified to improve performance by making an optimal nonlinear system. The method is illustrated by designing a nonlinear fuzzy logic control system for a headbox used for papermaking. A discrete linear quadratic regulator (DLQR) is first designed for this system. A nonlinear fuzzy logic control system is subsequently developed from the DLQR controller. The performance of these two control systems is then compared.
Substitution of Hydraulic for Pneumatic IC Engine Valve Control System
Authors: Sullivan Paul , Petersen Harry
Published: June 2008

Research into computer control of the operation of the engine intake and exhaust valves is continuing at Minnesota State University in Mankato to further the goals of improved gas mileage and reduced emissions from IC (internal combustion) engines. A major source of energy-wasting pumping losses can be reduced by controlling valve timing and duration, combined with the elimination of the throttle, while promoting more efficient combustion. An ideal system would allow complete variable computer control of valve lift and timing during all portions of the stroke cycles. Our first paper reported earlier Senior Design Project work, in which a spark ignition internal combustion engine was modified to allow computer control of the engine’s valves. These projects replaced the mechanically operated intake and exhaust valves with pneumatically operated valves controlled by computer in the form of a Programmable Logic Controller. The valves controlled by the solenoids switched compressed air to pneumatic cylinders that operated the existing poppet intake and exhaust valves on the engine. It was found that the use of compressible air was unsatisfactory for the higher RPMs due to the inability of the system to operate the valves quickly enough. Hydraulic operation could theoretically allow more accurate valve control at higher engine speeds. A follow-up research team found out that putting computer-controlled hydraulic valve actuation into operation on a real IC engine introduces other problems, however. We had hoped to present preliminary data from tests of the new hydraulic system, but inadequate hydraulic pressure plus equipment purchase order problems and hydraulic component failures allowed only limited testing using external power by the end of the semester. While we could not get the engine to run under its own power, the analysis pointed the way to future improvements. This paper summarizes the background and pneumatic valve results of the first paper, and discusses the operational issues and problems, and presents the analysis of the follow-up research into the use of hydraulic valve actuation.
A Framework for Efficient and More Realistic Haptics Applications
Authors: Luciano Cristian , Banerjee Pat , DeFanti Thomas , Mehrotra Sanjay
Published: June 2008

This paper describes the development of a generic framework for implementing realistic cross-platform haptic virtual reality applications. Currently, freely available Software Development Kits (SDKs) deal with a single Haptic Interaction Point (HIP), i.e. the tip of the haptic probe. However, many applications as path planning, virtual assembly, medical or dental simulations, as well as scientific exploration require object-object interactions, meaning any part of the complex 3D object attached to the probe collides with the other objects in the virtual scene. Collision detections and penetration depths between 3D objects must be quickly computed to generate forces to be displayed by the haptic device. In these circumstances, implementation of haptic applications is very challenging when the numbers, stiffness and/or complexity of objects in the scene are considerable, mainly because of high update rates needed to avoid instabilities of the system. The proposed framework meets this high requirement and provides a high-performance test bed for further research in algorithms for collision detection and generation of haptic forces.
Integration of Immersive Environment and RULA for Real-Time Study of Workplace Related Musculoskeletal Disorders in the Upper Limb
Authors: Shaikh Imtiyaz , Kim YoungJun , Jayaram Sankar , Jayaram Uma , Choi Hongsoo
Published: June 2008

The assessment of musculoskeletal disorders prevalent among industrial workers involved in manual tasks is a difficult and time-consuming process. This paper presents the integration of the rapid upper limb assessment (RULA) algorithm, a well-established ergonomic tool, with a virtual assembly tool (VADE), to facilitate the identification of potential upper limb injuries in assembly processes and identification of potential solutions. In this context, a parametric human model was embedded into the virtual assembly system. The posture of the worker is analyzed continuously (at each frame) in real-time, as he/she performs the task. This allows the engineer to try out different postures and assembly processes quickly to identify the best work environment set-up. One pilot study is presented in this paper to demonstrate the application of this concept. This pilot study (conducted jointly with an industry partner) clearly illustrates the validity and utility of this method in identifying and reducing manual assembly process related musculoskeletal stresses.
The Optimum Assignment of the Enthalpy Rise of the Heater
Authors: Chen Gang , Lu Xiaofeng , Amano R. S.
Published: June 2008

“Energy saving” and “environment protection” have been becoming key issues in the field of energy. A thermal power unit has a regenerative process, regardless the unit is reheating or non-reheating system, when the feedwater temperature and the stages of the regenerative cycle keep constant, there must have an optimum enthalpy rise assignment of the heater, which the turbine efficiency is the highest [1,3] .The optimum feedwater temperature is based on the optimum enthalpy assignment. However, at present, there is no better method to solve this problem. This paper presents a simple and effective method for the achievement of enthalpy rise of the heater. Industries can use this technology as a guide to achieve the enthalpy rise of the heater and improve the turbine efficiency and save the energy. The method is based on the theory of equivalent condensing steam loss investigated by the authors.
Robust Design Using Preference Aggregation Methods
Authors: Dai Zhihuang , Scott Michael J. , Mourelatos Zissimos P.
Published: June 2008

Robust design is a methodology for improving the quality of a product or process by minimizing the effect of variations in the inputs without eliminating the causes of those variations. In robust design, the best design is obtained by solving a multicriteria optimization problem, trading off the nominal performance against the minimization of the variation of the performance measure. Because these methods often combine the two criteria with a weighted sum or another fixed aggregation strategy, which are known to miss Pareto points, they may fail to obtain a desired design. To overcome this inadequacy, a more comprehensive preference aggregation method is combined into robust design. Two examples are presented to illustrate the effectiveness of the proposed method.
Non-Gradient Based Parameter Sensitivity Estimation for Robust Design Optimization
Authors: Gunawan S. , Azarm S.
Published: June 2008

We present a method for estimating the parameter sensitivity of a design alternative for use in robust design optimization. The method is non-gradient based: it is applicable even when the objective function of an optimization problem is non-differentiable and/or discontinuous with respect to the parameters. Also, the method does not require a presumed probability distribution for parameters, and is still valid when parameter variations are large. The sensitivity estimate is developed based on the concept that associated with each design alternative there is a region in the parameter variation space whose properties can be used to predict that design’s sensitivity. Our method estimates such a region using a worst-case scenario analysis and uses that estimate in a bi-level robust optimization approach. We present a numerical and an engineering example to demonstrate the applications of our method.
Production Cost Modeling to Support Product Family Design Optimization
Authors: Park Jaeil , Simpson Timothy W.
Published: June 2008

Product family design involves carefully balancing the commonality of the product platform with the distinctiveness of the individual products in the family. While a variety of optimization methods have been developed to help designers determine the best design variable settings for the product platform and individual products within the family, production costs are thought to be an important criterion to choose the best platform among candidate platform designs. Thus, it is prerequisite to have an appropriate production cost model to be able to estimate the production costs incurred by having common and variant components within a product family. In this paper, we propose a production cost model based on a production cost framework associated with the manufacturing activities. The production cost model can be easily integrated within optimization frameworks to support a Decision-Based Design approach for product family design. As an example, the production cost model is utilized to estimate the production costs of a family of cordless power screwdrivers.
Product Family and Platform Portfolio Optimization
Authors: de Weck Olivier L. , Suh Eun Suk , Chang David
Published: June 2008

In this paper, a methodology is presented to determine the optimum number of product platforms to maximize overall product family profit with simplifying assumptions. This methodology is attempting to aid various manufacturing industries who are seeking ways to reduce product family manufacturing costs and development times through implementation of platform strategies. The methodology is based on a target market segment analysis, market leader’s performance vs. price position, and a two-level optimization approach for platform and variant designs. The proposed methodology is demonstrated for a hypothetical automotive vehicle family that attempts to serve seven different vehicle market segments. It is found that the use of three distinct platforms maximizes overall profit by pursuing primarily a horizontal leveraging strategy.
Layered Manufacturing by Electrophotographic Printing
Authors: Kumar Ashok V. , Dutta Anirban
Published: June 2008

A layered manufacturing technique that uses electrophotography is described where powder is picked up and deposited using a charged photoconducting surface and deposited layer by layer on a build platform. A test bed was designed and constructed to study the application of electrophotography to layered manufacturing. The test bed can precisely deposit powder in the desired shape on each layer. The feasibility of printing powder layer by layer was demonstrated. The electric field required to transfer the powder on to the platform (or onto previously printed layers) was studied. It was found that corona charging the top layer of the part is necessary to continue printing powder as the part height increases.
Development of Knowledge Based System to Facilitate Design of On-Board Car Safety Systems
Authors: Ben Ahmed Walid , Bigand Michel , Mekhilef Mounib , Page Yves
Published: June 2008

The development of on-board car safety systems requires an accidentology knowledge base for the development of new functionalities as well as their improvement and evaluation. The Knowledge Discovery in accident Database (KDD) is one of the approaches allowing the construction of this knowledge base. However, considering the complexity of the accident data and the variety of their sources (biomechanics, psychology, mechanics, ergonomics, etc.), the analytical methods of the KDD (clustering, classification, association rules etc.) should be combined with expert approaches. Indeed, there is background knowledge in accidentology which exists in the minds of accidentologist experts and which is not formalized in the accident database. The aim of this paper is to develop a Knowledge Representation Model (KRM) intended to incorporate this knowledge in the KDD process. The KRM is implemented in a knowledge-based system, which provides an expert classification of the attributes characterizing an accident. This expert classification provides an efficient tool for data preparation in a KDD process. Our method consists of combining the modeling systemic approach of complex systems and the modeling cognitive approach KOD (Knowledge Oriented Design) in knowledge engineering.
A Design Alternatives Assessment and Management Approach
Authors: Nowak Pierre , Eynard Benoiˆt , Roucoules Lionel
Published: June 2008

One of the objectives of concurrent engineering has been to integrate more and more knowledge as soon as possible during the product development process. In such a method and owing to designer creativity, new design solutions are carried out. Design alternatives then appear; the differences can be relative to the functions, the technology, the materials or the manufacturing process as well. This paper presents some first specifications in modelling those design alternatives. Much more design solutions can then be kept in designers’ mind instead of focusing on the a priori best solution. The final solution is therefore chosen depending on every point of view involved in the design process. First of all this work aimed at defining the new knowledge that have to be taken into account in the product modelling in order to support the design alternatives management. Those new model elements must currently be integrated or linked with already-known product and design process models. The alternatives modelling has secondly been tested on very simple design examples. Afterwards, the design of a surgical simulator has been carried out that pointed out the real benefits and the feasibility of the alternatives modelling.
Design Optimization of Vehicle Structures for Crashworthiness Using Equivalent Mechanism Approximations
Authors: Hamza Karim , Saitou Kazuhiro
Published: June 2008

Passenger vehicle crashworthiness is one of the essential vehicle attributes. According to National Highway Traffic Safety Administration (NHTSA), there were over six million vehicle crashes in the United States in the year 2000, which claimed the lives of more than forty thousand persons. Vehicle crashworthiness is difficult to satisfy in a manner appeasing to other design decisions about the vehicle. This paper aims at developing a novel methodology for crashworthiness optimization of vehicle structures. Based on observations of the manner of structural deformation, the authors propose the abstraction of the actual vehicle structure, which is to be represented as a linkage mechanism having special nonlinear springs at the joints. The special springs are chosen to allow the motion of the mechanism to capture the overall motion of the actual vehicle structure. It thus becomes possible to optimize the mechanism, which is an easier task than directly optimizing the vehicle structure. A realization of the optimized mechanism is then performed to obtain an equivalent structure, and then direct optimization of the realized structure is performed for further tuning. The study presented shows the success of the proposed approach in finding better designs than direct optimization while using comparatively less computational resources.
The Effect of Tempering (Artificial Aging) on the Crashworthiness Performance of Mass-Efficient Extruded Aluminum Structures
Authors: Mayer Robert R. , Peterson Brian , Mishra Raj , Sachdev Anil
Published: June 2008

The effect of tempering (artificial aging) on the axial crush strength of four cell extruded rectangular aluminum alloy (AA) 6061 and 6063 tubes is developed in this report. Increasing the aging time from the press quenched condition increases the flow strength of the material and also increases the axial energy absorbed up to a point when the material showed fracture. Good predictions were made between experimental, theoretical, and numerical mean crush loads for various tempers of AA6061 and AA6063, except in the cases where a large amount of fracture was present. A recommended temper time of three hours was obtained for AA6063, with an increase in mean crush load of 60%. A recommended temper time of six hours was obtained for AA6061 with an increase in mean crush load of 40%. These results will be useful in future aluminum automotive body projects, both for their predictive capability, and for the temper recommendations.
Bayesian Approximation-Assisted Optimization Applied to Crashworthiness Design of a Pickup Truck
Authors: Farhang-Mehr A. , Azarm S. , Diaz A. , Ravisekar A.
Published: June 2008

Direct application of most optimization techniques, especially Multi-Objective Evolutionary Algorithms (MOEAs) that require many response evaluations, is computationally prohibitive for most real-world engineering simulations. In this paper, an approximation-assisted approach to multi-objective optimization of computationally expensive response functions is presented. We employ a Bayesian approach, referred to as Sequential MAXimum Entropy Design (SMAXED), for design of experiments and global approximation of an expensive finite-element model, i.e., crash event simulation of front end of a pick-up truck. The approximation model is optimized using a multi-objective genetic algorithm. It is shown that while the approach dramatically reduces the computational costs, it also finds a good estimate to the Pareto-optimal solution set for such a complex problem.
Topology Optimization of Heat-Resistant Structures
Authors: Diaz Alejandro R. , Benard Andre
Published: June 2008

The standard problem of finding the optimal layout of structural material associated with maximum stiffness is expanded to include consideration of thermal criteria. The problem is posed as a three-phase layout problem where the phases include an insulating or fire retardant material and an unknown distribution of heat sources, in addition to the structural material. The model used is simple, yet results suggest that the introduction of measures to control the temperature in the structure when subjected to significant heat transfer rates can result in layouts that differ substantially from solutions where thermal issues are ignored.