bluuebunny/crossref_metadata_2025 huggingface dataset:
Ontology-Based Semantic Approach for Communication in Engineering Design Evaluation
Authors: Zhan Pei , Jayaram Uma , Jayaram Sankar
Published: June 2008

The primary objective of this paper is to conceptualize and develop an approach using semantics to integrate engineering applications for design evaluations. Our approach, coined OADE (Ontology-based Adaptive Design Evaluation), will have as components representation tools, ontology builders, ontology projecting tools, custom tools, and communication tools. In the proposed integration framework, ontologies in different domains will be built and integrated with the domain-specific applications. Semantics will be represented in domain-specific ontology and translated using ontology projection. The process of ontology projection calculates the similarities between concepts related to diverse viewpoints and then translates them. A design decision can thus be described using the common concepts across the diverse entities.
Nonlinear Modeling and Experimental Identification of Hemispherical Soft Pads for Robotic Manipulators
Authors: Tiezzi Paolo , Vassura Gabriele , Biagiotti Luigi , Melchiorri Claudio
Published: June 2008

In this work the dynamic contact of hemispherical indenter covered by a thick viscoelastic layer and pressed against a flat rigid surface is modelled. The goal is to investigate the dynamic behavior of robotic fingertips composed by an inner rigid structure covered by a soft layer, mimicking the human biological model. A quasi-linear model, frequently used to describe the behavior of soft and pulpy biological tissues, is adopted in order to achieve a compromise between the simplicity of classical linear models and the difficulty of nonlinear approaches. Two different materials (a polyurethane gel and a silicon rubber) have been experimentally tested in order to find the parameters of the model and to validate it. Finally, the advantage of the use of digital filters method in identification process is exploited, so that the identification becomes suitable for online process.
Study on Product Reliability Based on Fuzzy Chance Constrained Programming
Authors: Fengli Huang , Zhao Yanwei
Published: June 2008

Due to the uncertainty of parameters of product reliability design, based on the Liu’s fuzzy chance constrained theory, provides a fuzzy chance constrained programming model of product reliability design that has N subsystems and several designs can be chosen in every subsystem. On the basis of Liu’s fuzzy simulated based on genetic algorithm, an improvement has been made on checking fuzzy simulation for the fuzzy chance constrains in this paper. And it provides the steps of a fuzzy simulated based on genetic algorithm. At the end of the paper, an instance is given to prove that the improvement is reliable, and the searching space from feasible and infeasible field can converge to the optimal solution. The searching speed can also be improved.
Computational Fluid Dynamics Investigation of Cylindrical Filter Element
Authors: Al-Hajeri M. H. , Witry A.
Published: June 2008

Cylindrical or candle filters have been developed for cleaning the hot combustion gas streams upstream of the turbine in a combined cycle power plant. To obtain continues operation a periodic cleaning is necessary and the cleaning efficiency depends on the distribution of the filtration cake. Consequently uniform particle deposition on the filter element surface is desired. The flow around three filter elements in cross flow is investigated computationally using the commercial code FLUENT. Three filter elements are placed in a two-dimensional rectangle duct with fixed face velocity and varying the velocity ratio between the approach and face velocity. Particle trajectories are obtained for a number of particle diameters and different inlet (approach) velocity to face filtration velocity ratios to investigate the behavior of particles around the filter element.
A CAN-Based P2P Infrastructure for Semantic Web Services
Authors: Channa Nizamuddin , Li Shanping , Shi Wei , Peng Gang
Published: June 2008

After merger of Web Services and Semantic Web, Semantic Web Services (SWS) has received a lot of attention from researchers due to its ability of automatic Web Service discovery, execution and composition. Currently Web Service systems, which publish WSDL-described Web Services in UDDIs, cannot support SWS and UDDI has become the bottleneck of the whole system and would cause single node failure problems. Therefore, we propose a CAN-based P2P system to replace traditional UDDI, by distributing the functions of the UDDI among all the peers in the P2P network. At the same time, we design an ontology-based mechanism, guaranteeing every service would be registered on a specific peer in the CAN-based P2P network, according to the service’s ontology. By replacing the UDDI, our system improves the scalability and stability of the SWS system, and realizes an efficient ontology-based discovery of Semantic Web Services.
Finite Element Method for Dynamic Analyzing in the Underground Structure
Authors: Qi Hui , Li Wentao , Li Mingqiang
Published: June 2008

In this paper, the model of wave finite element is founded by analyzing the issue of the foundation containing channels excited by transient SH-wave in FEM. The method’s rationality and the simulation infinite territory issue are discussed. The establishment artificial boundary to satisfy the unlimited extent the request, as well as the unit division and the time integral length of stride selection problem are researched. The numerical value of the displacement of the cavity is obtained by calculating the dynamic responds of the underground U-shaped structure with ANSYS. Examples are provided to support the discussion.
Interfacing FEA and Multibody Simulation Through Component Mode Synthesis
Authors: Bayoumi Hassan N.
Published: June 2008

Many of the currently available commercial multibody systems simulation packages are limited to rigid bodies linked by joints. Accurate dynamic analysis of multibody systems might require consideration of the flexibility of some components. Finite element analysis is generally the method of choice for structural dynamic analysis. Implementation of a fully featured reliable finite element capability within well-established commercial multibody systems software is not an easy task. A practical solution is to interface commercial finite element analysis software with commercial multibody systems software. This paper describes the theory and implementation aspects of such an interface. The interface is based on the Craig-Bampton method of component mode synthesis. The power of this technique is that it presents customers of commercial multibody simulation software with a practical and reliable tool to address component flexibility. The technique has been implemented to interface two major commercial simulation packages. Two practical applications, a flexible connecting rod and a flexible hard disk drive head-stack assembly, are discussed.
Improved Current Statistic Model and Adaptive Filtering
Authors: Hu Hongtao , Jing Zhongliang
Published: June 2008

Current statistical model needs to pre-define the value of maximum accelerations of maneuvering targets. So it may be difficult to meet all maneuvering conditions. In this paper a novel adaptive algorithm for tracking maneuvering targets is proposed. The algorithm is implemented with fuzzy-controlled current statistic model adaptive filtering and unscented transformation. The Monte Carlo simulation results show that this method outperforms the conventional tracking algorithm based on current statistical model.
Application of Experimental and Finite Element Methods to Analyse the Effect of Inner Diaphragms of Automotive T-Frame
Authors: Tan CheeFai , Hj Shafie Mohd Hazani , Shamsudin Shamsul Anuar , Said Md. Radzai
Published: June 2008

The framework of the automotive body structure is comprised of thin walled section members in the form of overlapping sheet metals fastened by spot-welds. In analysing the structure of the vehicle body, it is assumed that the intersecting angles at which the members are joined together varies according to the external forces. These frame joints are subject to dynamic and static loads. Experiments and finite element analysis can determine joint rigidity. The effective design of the vehicle T-joint can maximise passenger safety and reduce the vehicle weight. Thus, these were conducted to investigate the deflection of the vehicle T-frame. This paper discuss the behaviour of the T-frame under a specific loading. In addition, a series of T-frame with inner diaphragms (baffles) at various locations in the sill member were designed in order to investigate the effect of the inner diaphragms and non-continuous closed hat section in the sill member. The results from the experimental tests were compared with the results of the finite element analysis. We demonstrated the effectiveness of the inner diaphragm in the automotive T-frame.
Disk Design Methodology for Reducing Blade Vibration in Turbine Engine Rotors
Authors: Baik Sanghum , Castanier Matthew P. , Pierre Christophe
Published: June 2008

The optimal design of the disk of a turbine engine rotor stage is examined as a means of reducing worst-case blade vibration and stress levels. The cross-sectional profile of the disk is modified in search of an optimum that achieves minimum weight while ensuring that the stresses due to centrifugal loading and vibration remain below a safe level, as defined by a Goodman diagram, even when blade mistuning is introduced. In order to predict the vibration response of a tuned or mistuned bladed disk, a reduced-order modeling technique is employed. Rotational effects are included in the reduced-order model, and a response metric based on vibration energy is used to estimate the dynamic stress level. This process enables the evaluation of a design configuration in a manner that is sufficiently rapid to enable a comprehensive design optimization process. Using two example systems, the developed design methodology is found to yield bladed disk designs that are less sensitive to blade mistuning, thus reducing maximum stress and alleviating high cycle fatigue failure concerns.
Forced Response of Translating Media With Variable Length and Tension and a Mass-Spring Termination
Authors: Chen Yan , Zhu W. D.
Published: June 2008

The lateral response of vertically translating media with variable length and tension and a mass-spring termination is determined for general initial conditions and external excitation. The translating media are modeled as a taut string and tensioned beams with pinned and fixed boundary at the upper end. In each case a spring-mass sub-system is attached at the lower end of the translating medium. The rates of change of the energies in each case are analyzed and interpreted from the control volume and system viewpoints. The models are used to predict the forced response of cable-car systems in high-speed elevators due to building sway, pulley eccentricity, and guide-rail irregularity. The optimal design of the suspension stiffness of the car is investigated. A resonance condition y(x,t) that leads to dramatically increasing vibratory energy of the cable-car system is identified.
Evaluating the Flexural Stiffness of Compliant Hinges Made With Close-Wound Helical Springs
Authors: Lotti Fabrizio , Zucchelli Andrea , Reggiani Barbara , Vassura Gabriele
Published: June 2008

Advantages and problems related to the use of compliant hinges in articulated robotic structures are briefly discussed. A novel kind of elastic joint made with close-wound helical springs is then described. It is capable of large angular displacement so that it can be conveniently applied in manipulation devices like the humanoid robot hand developed at the University of Bologna. The results of this application encourage a systematic investigation on the properties of this kind of joints, not previously described in the literature, aiming at mechanical characterization and definition of design criteria. To this purpose, the paper outlines a general investigation programme, where theoretical models, Finite Elements analysis and experiments jointly contribute to the evaluation of the hinge stiffness and to the identification of influential design parameters. Preliminary results related to evaluation of the stiffness about the principal bending axis are then examined and discussed, comparing the results obtained from experiments with those achieved by means of a simplified mathematical model and the correspondent FE analysis. An auxiliary parameter is finally introduced in order to define a general criterion for the design of spring-based hinges subjected to large deflection.
Self-Adjustable Docking Mechanism With Passive Linkage for Mobile Robot
Authors: Choi Hyun Do , Lee Kung Wun , Woo Chun-Kyu , Rew Ho Seon , Kim Soo Hyun , Kwak Yoon Keun
Published: June 2008

Autonomous mobile robot increasingly expands its functionality into various applications where the long-term autonomous capability is necessary. These applications, warehouse service, building inspection, exploration of unknown terrains and military reconnaissance, require the mobile robot to correspond with the command of remote operators or environments. To meet this requirement, automatic recharging station can be used for a robot not to be taken offline. However, the range of docking error is wide by various homing algorithms and kinds of sensors. This paper describes a new docking mechanism developed to compensate entry error of robot in homing and to maintain robust state in the process of recharging battery without actuators and sensors. The proposed mechanism is self-adjustable to position and orientation of robot and reconfigures its states by driving force of mobile robot without any active energy elements. The geometric parameters are determined to avoid mechanical interference in docking procedure and specifications of springs are obtained from optimization which maximizes the grip force with constraint induced at each docking process. The docking mechanism can compensate for ±5cm lateral offset error and ±30° orientation error of mobile robot and holds it over 20N load after docking is finished.
Free-Form Feature Representation and Comparison
Authors: Ferrari David , West Geoff , Rolfe Bernard , Cardew-Hall Michael
Published: June 2008

Knowledge Management systems have been applied to several areas in the manufacturing industry. These applications have been predominately text based, however, much of manufacturing’s information is related to geometric features. In this paper we describe a representation and content-based search method such that given a geometric specification, the knowledge of previous designs having similar feature requirements is returned. The technique uses curvature based shape index segmentation to construct an attributed graph-like descriptor for 2.5D free-form surface features, such as those found on stamped components. Efficient edit distance methods are applied for search. Experiments on a database of freeform features indicate feasible runtimes with favourable results.
Extraction of Load Information From Photoelastic Images Using Neural Networks
Authors: Dubey Venketesh N. , Grewal Gurtej S. , Claremont Denzil J.
Published: June 2008

Photoelastic materials develop colored fringes under white light when subjected to mechanical stresses which can be viewed through a polariscope. This technique has traditionally been used for stress analysis of loaded components, however, this can also be potentially used in sensing applications where the requirement may be measurement of the stimulating forces causing the generation of the fringes. This leads to inverse photoelastic problem where the developed image can be analyzed for the input forces. However, there could be infinite number of possible solutions which cannot be obtained by conventional techniques. This paper presents neural networks based approach to solve this problem. Experiments conducted to prove the principle have been verified with theoretical results and finite element analysis of the loaded specimens. The technique, if fully developed, can be implemented for any generalized case involving complex fringe patterns under different loading conditions for whole-field analysis of the stress pattern, which may find application in a variety of specialized areas including biomedical engineering and robotics.
Topology Synthesis and Classification of Low-Mobility Parallel Mechanisms
Authors: Yang Xiangdong , Yang Dongchao , Xiong Jing , Chen Ken , Yang Ting-Li
Published: June 2008

Topology synthesis of low-mobility parallel mechanisms is an important direction of mechanism research. At present, various systematic methods for topology synthesis have been proposed, and large numbers of new mechanisms that satisfy the motion requirements have been synthesized through step-by-step deducing. However, some fundamental problems are ignored. In this paper, some significant synthesis methods are compared from the aspects of the description of output character, limb structure synthesis and geometrical relationship between limbs. The commonly existent problems are analyzed, including the strict description of the output character of the moving platform and the instantaneous mechanisms in the process of topology synthesis. The limitation of existent methods is also indicated. Moreover, a classifying method for low-mobility parallel mechanisms from the viewpoint of topology synthesis is proposed. This classification has guiding effect for synthesis, analysis and application of parallel mechanisms.
Industry-Academia Computer Aided Engineering Undergraduate Research Projects
Authors: Schonning Alexandra , Cox Daniel
Published: June 2008

Florida’s First Coast Manufacturing Innovation Partnership (MIP), sponsored by the National Science Foundation (NSF), promotes collaboration between academia and local industry members by providing a shared resource center. The local industry provides the university with research opportunities for its undergraduate students in areas of mechanical engineering design, manufacturing, and analysis and the university provides the local industry with technical resources. This paper outlines how this collaborative effort is structured, what types of projects are undertaken, and what the benefits are to academia, industry, and society in general. In particular, the paper describes three computer aided engineering (CAE) projects, addresses how these industry-academia projects help achieve the goals of the MIP program, and how these projects help improve the CAE skills of the future workforce.
Spherical Bistable Micromechanism
Authors: Lusk Craig P. , Howell Larry L.
Published: June 2008

A new micromechanism, the Spherical Bistable Micromechanism (SBM), is described. The SBM has several advantageous features, which include: two stable positions that require power only in transitioning from one to the other; robustness against small disturbances; and an output link with a stable out-of-plane orientation. The SBM may be useful in applications such as 2-D optical mirror arrays or in erecting out-of-plane structures.
Aeronautical Planar Flank Milling Automation: Computing the G-Zones
Authors: Harik Ramy , Ris Gabriel
Published: June 2008

Flank milling process is commonly applied in the aeronautical industry. It consists of manufacturing mechanical parts using the side of a machinning tool. This process is relevant to be less time consuming as it delivers better surface quality. However, flank milling can only be applied on ruled surfaces. In this article, we cover flank milling application on planar surfaces, a particular ruled surface type. In recent works we presented how to extract planar surfaces milling directions by using expertise provided through our industrial application. We take this study further, where we propose a validation for the proposed milling directions. This validation requires at first a translation of the problem from 3D to 2D. Then, by applying several proposed algorithms we extract for each direction its L-Zone. An L-Zone is the term we use to identify the unmachined part area using a particular milling direction. By intersecting the different L-Zones we obtain the G-Zone that consists of the total unmachined area. Computing the G-Zone for each planar surface indicates the ability of this surface to be flank milled. The proposed study is part of an effort to automate process planning of aeronautical parts. Automating this particular trade can result in a critical reduction of time, effort and costs in aeronautical industries, mainly due to having small production batch.
The Development of Ancient Earthquake Instruments
Authors: Yan Hong-Sen , Hsiao Kuo-Hung
Published: June 2008

This paper studies sensing element designs in ancient seismometers and describes the developments of ancient earthquake instruments. A basic seismograph comprises a seismometer, a recording system, and a timing system. The major difficulty in the development of a seismograph was the design of the seismometer. And, the break through was the use of a pendulum system as a sensing element that responded to ground motion and did not move with the ground. Early seismoscopes were primarily intended to determine that an earthquake had happened. The first seismoscope invented by Zhang Heng was Hou Feng Di Dong Yi made in ancient China around the year 132 AD. The truly successful seismographs were first designed and built in the 1880s by a group of British scientists in Japan. In 1906, Boris Galitzin developed a working electromagnetic seismograph with a great sensitivity. Finally, a comparison with the recording systems of ancient seismographs is concluded.
Engineering Product Design Optimization for Retail Channel Acceptance
Authors: Williams N. , Azarm S. , Kannan P. K.
Published: June 2008

Significant recent research has focused on the marriage of consumer preferences and engineering design in order to improve profitability. The extant literature has neglected the effects of channel markets which are increasingly prevalent. At the crux of the issue is the fact that channel dominating retailers, like Wal-Mart, have the ability to unilaterally control manufacturer production decisions as gatekeepers to the consumer or market. In this paper, we propose a new methodology that accounts for this power asymmetry. A chance constrained framework is used to model retailer acceptance of possible engineering designs and accounts for the important effect on the profitability of the retailer’s assortment through a latent class estimation of demand from conjoint surveys. Our approach allows the manufacturer to optimize a product design for profitability while reliably ensuring that the product will make it to market by making the retailer more profitable with the addition of the new product. As a demonstrative example, we apply the proposed approach for product design selection in the case of an angle grinder. For this example, we analyze the market and are able to improve expected manufacturer profitability while simultaneously presenting the decision maker with tradeoffs between slotting allowances, market share, and risk of retailer acceptance.
Case-Based Reasoning for the Design of Micro-Electro-Mechanical Systems
Authors: Cobb Corie L. , Agogino Alice M.
Published: June 2008

Although Micro-Electro-Mechanical Systems (MEMS) are forming the basis for a rapidly growing industry and fields of research, many MEMS designers still rely on back-of-the-envelope calculations due to a lack of efficient computer-aided design (CAD) tools that can assist with the initial stages of design exploration. This paper introduces case-based reasoning (CBR) techniques to the design of MEMS, as part of a larger MEMS synthesis framework currently under development at UC Berkeley. Having the ability to draw upon past design knowledge is advantageous to the MEMS designer, allowing reuse and modification of previous successful designs to help deal with the complexities of a new design problem. CBR utilizes past successful MEMS designs and sub-assemblies as building blocks stored in an indexed library. Reasoning tools find cases in the library with solved problems similar to the current design problem in order to propose promising conceptual designs. This paper discusses case representation and case library design as well as the results of case retrieval studies, focusing on MEMS resonant structures. The paper recommends strategies for integrating the MEMS case library with evolutionary computation when parameter optimization over the retrieved conceptual designs is not sufficient or there are gaps of knowledge in the case library.
Synthesis of a Compensated Kick Pattern for Humanoid Robots Using Conservation Laws
Authors: Meghdari Ali , Tamaddoni Seyed Hossein , Jafari Farid
Published: June 2008

The motivation of this work is to synthesize a kicking pattern for a humanoid robot with consideration of various objectives such as retaining its balance even after the kick is done and reducing the undesired angular momentum using both hands and torso. This kick pattern is designed so that a desirable ball velocity is achieved. In this paper, the law of conservation of angular momentum is used to generate a less energy consuming trajectory. Effectiveness of the proposed method is verified using computer simulation and is tested on Sharif CEDRA humanoid robot.
A Contact Force Solution for Non-Colliding Contact Dynamics Simulation
Authors: Sharf Inna , Zhang Yuning
Published: June 2008

Rigid-body impact modeling remains an intensive area of research spurred on by new applications in robotics, biomechanics, and more generally multibody systems. By contrast, the modeling of non-colliding contact dynamics has attracted significantly less attention. The existing approaches to solve non-colliding contact problems include compliant approaches in which the contact force between objects is defined explicitly as a function of local deformation, and complementarity formulations in which unilateral constraints are employed to compute contact interactions (impulses or forces) to enforce the impenetrability of the contacting objects. In this article, the authors develop a novel approach to solve the non-colliding contact problem for objects of arbitrary geometry in contact at multiple points. Similarly to the complementarity formulation, the solution is based on rigid-body dynamics and enforces contact kinematics constraints at the acceleration level. Differently, it leads to an explicit closed-form solution for the normal forces at the contact points. Integral to the proposed formulation is the treatment of tangential contact forces, in particular the static friction. These friction forces must be calculated as a function of microslip velocity or displacement at the contact point. Numerical results are presented for three test cases: 1) a thin rod sliding down a stationary wedge; 2) a cube rotating off the stationary wedge under application of an external moment and 3) the cube and the wedge both moving under application of a moment. To ascertain validity and correctness, the solutions to frictionless and frictional scenarios obtained with the proposed formulation are compared to those generated by using a commercial simulation tool MSC ADAMS.
Heterogeneous Design Optimization From the Microstructure
Authors: Cox Jordan J. , Adams Brent L. , Fullwood David T. , Halverson Denise
Published: June 2008

Designers have for some time had powerful tools that allow optimization of geometric design using, for example, parametric design techniques. However, these optimization strategies utilize an incomplete model in the design process. An assumption often made throughout the design process is that the material properties are homogeneous. However, it is recognized that engineered materials may have significant non-homogeneity, which often manifests itself in an undesirable manner (e.g. in the heat affected zone). In an ideal world, the non-homogeneity could be used to improve a design. A designer would have full control over the heterogeneous design of a product, being enabled to optimize both the material properties and geometry concurrently. Recent developments in microstructure sensitive design (MSD) have now made the problem of optimizing over both geometry and material structure accessible. The inverse problem of designing material to achieve desired properties is being tackled. The latest techniques allow a designer to search the property closures of materials for the optimum theoretical microstructures. Furthermore, work has started in terms of linking the space of theoretical microstructures with manufacturing techniques that are currently available for manipulation of the microstructure of polycrystalline materials. This paper demonstrates how the latest available MSD tools may be applied to the design process. A curved rod is optimized to maintain certain critical physical properties, while meeting certain geometrical criteria. The result is a local reduction in radius of 20% without significant reduction in properties. While the manufacturability of this particular case study is not specifically addressed, the potential future directions for such design tools are discussed and some practicalities in terms of bridging the gap between theoretical microstructures and available materials are reviewed.
Flexible Product Platforms: Framework and Case Study
Authors: de Weck Olivier L. , Suh Eun Suk
Published: June 2008

Customization and market uncertainty require increased functional and physical bandwidth in product platforms. This paper presents a platform design process in response to such future uncertainty. The process consists of seven iterative steps and is applied to an automotive body-in-white (BIW) where 10 out of 21 components are identified as potential candidates for embedding flexibility. The method shows how to systematically pinpoint and value flexible elements in platforms. This allows increased product family profit despite uncertain variant demand and specification changes. We show how embedding flexibility suppresses change propagation and lowers switch costs, despite an increase of 34% in initial investment for equipment and tooling. Monte Carlo simulation results for 12 future scenarios reveal the value of embedding flexibility.
Variation Analysis of a Two Link Planar Manipulator Using Polynomial Chaos Theory
Authors: Voglewede Philip A. , Monti Antonello
Published: June 2008

Understanding how manufacturing variation affects manipulator fit and function is of the utmost importance. There are currently many techniques to determine these effects. Many of them for robotic manipulators only apply to the static analysis, but there is a need to determine the dynamic effects. This paper outlines how polynomial chaos theory (PCT) can be utilized to solve both the static (aka tolerance stack-up) and dynamic analyses. To show the power of the procedure, it is applied to a simple planar two link manipulator with geometric variation of the link lengths.
Designing Product Forms Using a Virtual Hand and Deformable Models
Authors: Shieh Meng-Dar , Yang Chih-Chieh
Published: June 2008

This paper presents a computer-aided conceptual design system for developing product forms. The system integrates a virtual hand, which is manipulated by the designer, with deformable models representing the product forms. Designers can use gestural input and full hand pointing in the system to discover potential new ways for product form design. In the field of industrial design, styling and ergonomics are two important factors that determine a successful product design. Traditionally, designers explore possible concepts by sketching their ideas and then using clay or foam mock-ups to test them during the early phases of product design. With our deformable modeling simulation system, we provide a useful and efficient tool for industrial designers that enable to produce product form proposals efficiently without unnecessary trial and error. Designers can input pre-scanned 3D raw data or a 3D CAD model as an initial prototype. Then, the input model is given the material’s elastic property via the construction of a volume-like mass-spring-damping system. The virtual hand in the system constantly changes gestures as the designer manipulates it with a glove-based input device. The product form will be deformed or shaped according to the amount of force exerted by the virtual hand. A mesh smoothing feature called “PN-triangle” is also used to improve the appearance of the deformed model. Finally, a physical prototype with volume and weight is generated using a rapid prototyping machine. Designers can use these mock-ups to conduct further ergonomic evaluations.
Product Optimization Incorporating Discrete Design Variables Based on Decomposition of Performance Characteristics
Authors: Yoshimura Masataka , Yoshimura Yu , Izui Kazuhiro , Nishiwaki Shinji
Published: June 2008

In order to obtain superior design solutions, the largest possible number of design alternatives, often expressed as discrete design variables, should first of all be considered, and the best design solution should then be selected from this wide set of alternative designs. Also, product designs should be initiated from the earliest possible stages, such as the conceptual and fundamental design stages, when discrete rather than continuous design variables have primacy. Although the use of discrete design variables is fundamentally important, this has implications in terms of computational demands and the accuracy of the optimized solution. This paper proposes an optimization method for product designs incorporating discrete design variables, in which hierarchical product optimization methodologies are constructed based on decomposition of characteristics and/or extraction of simpler characteristics. The optimizations are started at the lowest levels of the hierarchical optimization structure, and proceed to the higher levels. The discrete design variables are efficiently selected and optimized as smaller sub-optimization problems at the lowest hierarchical levels, while the optimum solutions for the entire problem are obtained by conventional mathematical programming methods. Practical optimization procedures for machine product optimization problems having several types of discrete design variables are constructed, and some applied examples demonstrate their effectiveness.
Function Generation With Finitely-Separated Precision Points Using Geometric Constraint Programming
Authors: Kinzel Edward C. , Schmiedeler James P. , Pennock Gordon R.
Published: June 2008

This paper explains how Geometric Constraint Programming can be applied to solve function generation problems with finitely-separated positions using a number of different mechanisms. Geometric Constraint Programming uses the sketching mode of commercial parametric computer-aided design software to create kinematic diagrams whose elements are parametrically related so that when a parameter is changed, the design is modified automatically. Geometric constraints are imposed graphically through the user interface, and the numerical solvers integrated into the software solve the relevant systems of non-linear equations without the user explicitly formulating those equations. A key advantage of using Geometric Constraint Programming for function generation is that the same approach can be applied to any mechanism, so no unique algorithms are required. Furthermore, because the implementation is relatively straightforward regardless of the chosen mechanism, the designer can quickly and easily generate solutions for a large number of precision points and/or with complex mechanisms to provide a very accurate match to the desired function. Examples of function generation with a four-bar linkage, a six-bar linkage, and a seven-bar linkage illustrate the benefits of the proposed methodology.
Optimal Linkage Design for Bicycle Power Transmission Using Symmetric Four-Bar
Authors: Nelson Carl A.
Published: June 2008

Use of a symmetric crank-rocker four-bar linkage is presented as an alternative to the standard bicycle crank. With the coupler being the driven link, a kinematic and force-transmission analysis is presented. Results of constrained nonlinear optimization for geometric synthesis show a substantial improvement in mechanical efficiency compared to the state of the art. Dead-center positions are also eliminated. Potential applications to other linear-to-rotary power transmission devices, such as internal-combustion engines, are also discussed.
On Adaptive Sampling for Single and Multi-Response Bayesian Surrogate Models
Authors: Romero David A. , Amon Cristina H. , Finger Susan
Published: June 2008

In order to reduce the time and resources devoted to design-space exploration during simulation-based design and optimization, the use of surrogate models, or metamodels, has been proposed in the literature. Key to the success of metamodeling efforts are the experimental design techniques used to generate the combinations of input variables at which the computer experiments are conducted. Several adaptive sampling techniques have been proposed to tailor the experimental designs to the specific application at hand, using the already-acquired data to guide further exploration of the input space, instead of using a fixed sampling scheme defined a priori. Though mixed results have been reported, it has been argued that adaptive sampling techniques can be more efficient, yielding better surrogate models with less sampling points. In this paper, we address the problem of adaptive sampling for single and multi-response metamodels, with a focus on Multi-stage Multi-response Bayesian Surrogate Models (MMBSM). We compare distance-optimal latin hypercube sampling, an entropy-based criterion and the maximum cross-validation variance criterion, originally proposed for one-dimensional output spaces and implemented in this paper for multi-dimensional output spaces. Our results indicate that, both for single and multi-response surrogate models, the entropy-based adaptive sampling approach leads to models that are more robust to the initial experimental design and at least as accurate (or better) when compared with other sampling techniques using the same number of sampling points.
Explicit Solutions for Linear Partial Differential Equations Using Bezier Functions
Authors: Venkataraman P.
Published: June 2008

Solutions in basic polynomial form are obtained for linear partial differential equations through the use of Bezier functions. The procedure is a direct extension of a similar technique employed for nonlinear boundary value problems defined by systems of ordinary differential equations. The Bezier functions define Bezier surfaces that are generated using a bipolynomial Bernstein basis function. The solution is identified through a standard design optimization technique. The set up is direct and involves minimizing the error in the residuals of the differential equations over the domain. No domain discretization is necessary. The procedure is not problem dependent and is adaptive through the selection of the order of the Bezier functions. Three examples: (1) the Poisson equation; (2) the one dimensional heat equation; and (3) the slender two-dimensional cantilever beam are solved. The Bezier solutions compare excellently with the analytical solutions.
Platform-Based Design and Development: Current Trends and Needs in Industry
Authors: Simpson Timothy W. , Marion Tucker , de Weck Olivier , Ho¨ltta¨-Otto Katja , Kokkolaras Michael , Shooter Steve B.
Published: June 2008

Many companies constantly struggle to find cost-effective solutions to satisfy the diverse demands of their customers. In this paper, we report on two recent industry-focused conferences that emphasized platform design, development, and deployment as a means to increase variety, shorten lead-times, and reduce development and production costs. The first conference, Platform Management for Continued Growth, was held November–December 2004 in Atlanta, Georgia, and the second, 2005 Innovations in Product Development Conference — Product Families and Platforms: From Strategic Innovation to Implementation, was held in November 2005 in Cambridge, Massachusetts. The two conferences featured presentations from academia and more than 20 companies who shared their successes and frustrations with platform design and deployment, platform-based product development, and product family planning. Our intent is to provide a summary of the common themes that we observed in these two conferences. Based on this discussion, we extrapolate upon industry’s needs in platform design, development, and deployment to stimulate and catalyze future work in this important area of research.
Numerical Methods for Propagating Imprecise Uncertainty
Authors: Bruns Morgan , Paredis Christiaan J. J.
Published: June 2008

Since engineering design requires decision making under uncertainty, the degree to which good decisions can be made depends upon the degree to which the decision maker has expressive and accurate representations of his or her uncertain beliefs. Whereas traditional decision analysis uses precise probability distributions to represent uncertain beliefs, recent research has examined the effects of relaxing this assumption of precision. A specific example of this is the theory of imprecise probability. Imprecise probabilities are more expressive than precise probabilities, but they are also more computationally expensive to propagate through mathematical models. The probability box (p-box) is an alternative representation that is both more expressive than precise probabilities, and less computationally expensive than general imprecise probabilities. In this paper, we introduce a method for propagating p-boxes through black box models. Based on two example models, a new method, called p-box convolution sampling (PCS), is compared with three other p-box propagation methods. It is found that, although PCS is less expensive than the alternatives, it is still relatively expensive and therefore only justifiable when the expected benefits are large. Several directions for further improving the efficiency of PCS are discussed.
A Topological Model for the Representation of Meshing Constraints in the Context of Finite Element Analysis
Authors: Foucault Gilles , Le´on Jean-Claude , Cuillie`re Jean-Christophe , Franc¸ois Vincent , Maranzana Roland
Published: June 2008

The preparation of Finite Element analysis models (FE models) from Computer Aided Design (CAD) models is still a difficult task since its Boundary Representation (B-Rep) is often composed of a large number of thin faces, small edges, which are much smaller than the desired element size, and are not relevant for the meshing process. Such inconsistencies often cause poor-shaped FE elements, overdensities of elements, not only slowing down the computation of the FE solution, but also producing poor simulation results. In this paper, we present a “Mesh Constraint Topology” (MCT) model with adaptation operators aiming at transforming the CAD model in a FE model which only contains meshing-relevant edges and vertices, i.e. the explicit model of data intrinsic to the meshing process. Because the topology of faces adapted for meshing could contain interior edges, the MCT is represented with adjacency graphs instead of the B-Rep data-structure. We demonstrate how graphs provide efficient schemes to qualify interior and boundary entities, and facilitate the design of adaptation operators using high-level graph operators. Application and results are presented through adaptation issues of CAD models solved using MCT adaptation operators.
FEA-Based Design of Heterogeneous Objects
Authors: Shin Ki-Hoon
Published: June 2008

Finite Element Analysis (FEA) is an important step for the design of structures or components formed by heterogeneous objects such as multi-materials, Functionally Graded Materials (FGMs), etc. The main objective of the FEA-based design of heterogeneous objects is to simultaneously optimize both geometry and material distribution over the design domain (e.g., Homogenization Design Method). However, the accuracy of the FEA-based design wholly depends on the quality of the finite element models. Therefore, there exists an increasing need for generating finite element models adaptive to both geometric complexity and material distribution. This paper introduces a method for FEA-based design of heterogeneous objects. At the design stage, a heterogeneous solid model is first created by referring to the libraries of primary materials and composition functions that are already available in the field of material science. The heterogeneous solid model is then discretized into an object model onto which appropriate material properties are mapped. Discretization converts continuous material variations inside an object into stepwise variations. Next, the object model is adaptively meshed and converted into a finite element model. The meshing algorithm first creates nodes on the iso-material curves (or surfaces) of heterogeneous solid models. Triangular (or tetrahedral) meshes are then generated inside each iso-material region formed by iso-material curves (or surfaces). FEA using commercial software is finally performed to estimate stress levels. This FEA-based design cycle is repeated until a satisfactory solution is obtained. If the design objective is satisfactory, the object model is fed to the fabrication system where a process planning is performed to create instructions for LM machines. An example (FGM pressure vessel) is shown to illustrate the entire FEA-based design cycle.
Real-Time Deformation Simulation and a Design Support System for Wire Harnesses
Authors: Hashima Masayoshi , Senta Yosuke , Sato Yuichi
Published: June 2008

The layout design for the wire harnesses cannot be performed until a mechanical prototype is completed because of the necessity to determine the route and length in consideration of deformation. This paper proposes a real-time wire harness deformation simulation method that works together with a mechanism, and a design support system that allows virtual verification of wire harness layout using a 3-D product model. Real-time deformation simulation includes mechanical simulation calculating kinematics and harness shape simulation using a Bezier curve. The design support system allows interactive verification of exact length, maximum curvature and collision by simulating the behavior of a mechanism and a wire harness.
Representation of the Variable Chain Mechanisms With Sequential Movement
Authors: Huang Hsing-Hui
Published: June 2008

A mechanism that encounters a certain change in the number of links or degree of freedom during operation will also result the variation of the topological structure in every stage. Since the mechanisms with variable chain in different stages during operation have different topologies, but the applications of this kind of mechanisms are very extensively. And this also result the complications of representation of the topology thoroughly. Mechanisms with variable chain now always been represented by graph according to the topology of each stage, but hardly represent by using a formula. We would like to propose an approach to develop the function for representing the mechanism with variable chain that focus on the sequential movement, and help the representation of the operation not only by the graph but also by the function. According to the operation of the mechanisms with variable chain, the movement of the mechanisms can be classified into parallel system movement and sequential system movement. Parallel movement mechanisms are the mechanisms operate more than one links in the same time when giving an input; and when we give an input that can operate just only one link and effect and transfer the movement of the next one step by step, we can call this kind of mechanisms as sequential mechanisms. In this work we apply composite function for represent the movement of each stage, and also verified the representation by applying it on the existed examples.