bluuebunny/crossref_metadata_2025 huggingface dataset:
Shape Similarity Matching With Octree Representations
Authors: Zhang Jingsheng , Smith Shana
Published: June 2008

Shape matching is one of the fundamental problems in content-based 3D shape retrieval. Since there are typically a large number of possible matches in a shape database, there is a crucial need to perform shape matching efficiently. As a result, shapes must be reduced into a simpler shape representation, and computational complexity is one of the most important criteria for evaluating 3D shape representations. To meet the need, the investigators have implemented a new effective and efficient approach for 3D shape matching, which uses a simplified octree representation of 3D mesh models. The simplified octree representation was developed to improve time and space efficiency over prior representations. In addition, octree representations are rapidly becoming the standard file format for delivering 3D content across the Internet. The proposed approach stores octree information in XML files, rather than using a new data file type, to facilitate comparing models over the Internet. New methods for normalizing models, generating octrees, and comparing models were developed. The proposed approach allows users to efficiently exchange shape information and compare models over the Internet, in standardized data and data file formats, without transferring exact model files. The proposed approach is the first step in a project which will build a complete 3D model database and data retrieval system, which can be incorporated with other data mining techniques.
Augmented Reality E-Commerce Assistant System: Designing While Shopping
Authors: Lu Yuzhu , Smith Shana
Published: June 2008

Traditional electronic commerce (e-commerce) is facing a bottleneck because it cannot provide enough direct information about products to online consumers. The technology presented in this paper shows how Augmented Reality (AR) can be used to overcome the bottleneck and enhance e-commerce systems. The study also considers some key implementation issues. An AR e-commerce assistant system was developed, as an Internet plugin, which can be used on different kinds of computers and handheld devices when using the User-Centered Design method. Finally, a usability experiment was designed and a pilot test was also conducted, to compare the AR e-commerce assistant with traditional e-commerce and Virtual Reality (VR) e-commerce systems, and to verify that the AR e-commerce approach can be used to provide more direct information to online consumers. Results show that an AR e-commerce e-commerce system can provide more direct information about products than traditional or VR e-commerce systems.
Review of Metamodeling Techniques in Support of Engineering Design Optimization
Authors: Wang G. Gary , Shan S.
Published: June 2008

Computation-intensive design problems are becoming increasingly common in manufacturing industries. The computation burden is often caused by expensive analysis and simulation processes in order to reach a comparable level of accuracy as physical testing data. To address such a challenge, approximation or metamodeling techniques are often used. Metamodeling techniques have been developed from many different disciplines including statistics, mathematics, computer science, and various engineering disciplines. These metamodels are initially developed as “surrogates” of the expensive simulation process in order to improve the overall computation efficiency. They are then found to be a valuable tool to support a wide scope of activities in modern engineering design, especially design optimization. This work reviews the state-of-the-art metamodel-based techniques from a practitioner’s perspective according to the role of metamodeling in supporting design optimization, including model approximation, design space exploration, problem formulation, and solving various types of optimization problems. Challenges and future development of metamodeling in support of engineering design is also analyzed and discussed.
Exploiting Shape Similarity in Engineering Analysis
Authors: Gopalakrishnan Sankara Hari , Suresh Krishnan
Published: June 2008

Engineering analysis methods, such as the finite element method, are employed extensively to optimize complex engineering designs, but their success in conceptual product development is rather limited since numerous designs must be analyzed to cover the design space, and unfortunately, modern analysis methods can be tedious and time consuming in such scenarios. We propose here a novel analysis methodology for conceptual design wherein, given the simulation results and performance of one of the designs, one predicts upper and lower bounds on the performance of geometrically similar designs. The methodology rests on sound mathematical principles such as adjoint theory of boundary value problems, and is partly motivated by recent work on shape similarity exploitation in manufacturing wherein the cost of manufacturing a new part is estimated by retrieving the manufacturing costs of geometrically similar parts.
Design of Sub-Centimetre Underactuated Compliant Grippers
Authors: Boudreault Eric , Gosselin Cle´ment M.
Published: June 2008

This paper proposes a methodology for the design of a sub-centimetre underactuated compliant gripper. The gripper is optimized in order to maintain a proper force distribution on the phalanges and to avoid the deformation of soft objects. In order to keep the design simple and to limit the complexity of the control, each finger is based on a planar five-bar linkage. The five-bar mechanism is a well known and efficient underactuated mechanism. In this work, the revolute joints are replaced by flexible hinges in order to allow the miniaturization of the mechanism and make it easy to clean and sterilize. The behaviour of the prototypes built shows the effectiveness of the proposed method.
Optimal Design With Non-Normally Distributed Random Parameters, Conditional Probability, and Joint Constraint Reliabilities: A Case Study in Vehicle Emissions Regulations to Achieve Ambient Air Quality Standards
Authors: Chan Kuei-Yuan , Skerlos Steven J. , Papalambros Panos Y.
Published: June 2008

Making appropriate environmental policy decisions requires considering various sources of uncertainty. An air pollution example is formulated as a design optimization problem with probabilistic constraints, also referred to as reliability-based design optimization (RBDO). Environmental applications with a large number of constraints and significant model complexity present special challenges. In this paper an efficient active set strategy is integrated with a reliability contour surface approach to solve probabilistic problems with non-normal variable probability distributions. Discrete random parameters, which result in Bayesian probability, are also present and they are incorporated using delta function approximations. Joint constraint reliability that considers satisfying all regulatory constraints is also discussed. A demonstration example of setting the optimal vehicle speed limit while maintaining high reliability for CO and NOx standards of a residential area near two highway systems is included.
Haptic Cobot Exoskeleton: Concepts and Mechanism Design
Authors: Bosscher Paul , LaFay Eric
Published: June 2008

This paper presents a concept for a new type of haptic exoskeleton: REACH, the Robotic Exoskeleton with Advanced Cobot Haptics. This exoskeleton is the first ever concept for integrating cobot technology into a wearable exoskeleton device. This exoskeleton represents a significant improvement in haptic exoskeleton technology by providing high-performance haptic feedback to a user’s whole arm while at the same time guaranteeing the user’s safety. The overall design concept is presented, including the use of a spherical 3RRR parallel mechanism to implement the shoulder joint. The detailed design of the shoulder joint mechanism is then presented. The kinematic parameters of the shoulder joint are selected such that its range of motion matches the motion of a user’s shoulder while also avoiding collisions. In addition, to avoid singularities and maximize dexterity the mechanism design is optimized using the inverse condition number of the Jacobian matrix.
An Improved Genetic Algorithm for the Optimization of Composite Structures
Authors: Gantovnik Vladimir , Fadel Georges , Gu¨rdal Zafer
Published: June 2008

This paper describes a new approach for reducing the number of the fitness and constraint function evaluations required by a genetic algorithm (GA) for optimization problems with mixed continuous and discrete design variables. The proposed modification improves the efficiency of the memory constructed in terms of the continuous variables. The work presents the algorithmic implementation of the proposed memory scheme and demonstrates the efficiency of the proposed multivariate approximation procedure for the weight optimization of a segmented open cross section composite beam subjected to axial tension load. Results are generated to demonstrate the advantages of the proposed improvements to a standard genetic algorithm.
A Testbed to Support Collaboration Among Distributed Designers for Reverse Engineering, Re-Engineering and Fast Manufacturing
Authors: Siddique Zahed , Chang Kuang-Hua , Chen Zhiqiang , Edke Mangesh
Published: June 2008

This paper presents development of a testbed to support collaboration among a set of distributed engineers to reverse, re-engineer, and fast manufacture (RRF) components for aging aircrafts. This testbed allows a geographically distributed team to work on a design task both synchronously and asynchronously. Commercial off-the-shelf (COTS) software tools and equipment that support the RRF process have been identified, evaluated, and tested. An integration framework has also been developed and employed to create an RRF testbed. This testbed constructed using COTS software and equipment supports three major engineering tasks: the reverse engineering that supports recovering of technical data from worn sample parts, re-engineering that alters design for better performance or lower cost, and fast prototyping that incorporates advanced manufacturing technologies to produce functional or physical prototype of the part in small quantity in a short turnaround time. Traditional reverse engineering projects are ad-hoc, usually takes relatively long time to generate solid models from physical parts. The developed testbed utilizes commercial software to accomplish reverse engineering, re-engineer and fast manufacture using a systematic approach. A number of examples obtained from logistics centers have been employed to illustrate and demonstrate the capabilities established in the RRF testbed.
Optimum Disassembly Process With Genetic Algorithms for a Compressor
Authors: Huang Yuan Mao , Liao Yu-Chung
Published: June 2008

This study presents an optimum disassembly process with genetic algorithms. The disassembly sequence matrix including the interference matrix, the special connection relation and the contact matrix of a product are used to study the disassembly process. The genetic algorithms are utilized for the multi-objective function formed by the instability function, tool change function, disassembly direction function and inconvenient function due to the gravity to obtain the optimum disassembly process. The disassembly processes of a compressor are investigated and improved, and a redesigned compressor is recommended.
Improved Head Restraint Design for Safety and Compliance
Authors: Parkinson Matthew B. , Reed Matthew P.
Published: June 2008

The National Highway Traffic Safety Administration (NHTSA) recently revised Federal Motor Vehicle Safety Standard (FMVSS) 202, which governs head restraints. The new standard, known as FMVSS 202a, establishes for the first time in the U.S. a requirement for the fore-aft position of the head restraint. The fore-aft distance between the head restraint and headform representing a midsize male occupant must not exceed 55 mm when measured with the seat back angle set to 25 degrees. The goal of the rule change is to reduce the incidence of whiplash-associated disorders caused by rear impacts. Moving the head restraint closer to the head prior to impact decreases the amount of relative motion between the occupants’ heads and torsos and is believed to decrease the risk of soft-tissue neck injury. As manufacturers phase in seats that meet the new criterion, some vehicle models are producing complaints from drivers that the head restraint causes discomfort by interfering with their preferred head position, forcing them to select a more reclined seat back angle than they would prefer. To address this issue, an analysis of driver head locations relative to the seat was conducted using a new optimization-based framework for vehicle interior optimization. The approach uses simulations with thousands of virtual occupants to quantity distributions of postural variables of interest. In this case, the analysis showed that smaller-stature occupants are disproportionately likely to experience head-position interference from a head restraint that is rigidly affixed to the seat back. Using an analysis approach that considers both postural and anthropometric variability, design guidelines for the kinematics of an articulated head restraint are proposed. Such a restraint would provide optimal head restraint positioning across occupant sizes while minimizing interference.
Design of Compliant Mechanisms for Minimizing Input Power in Dynamic Applications
Authors: Tantanawat Tanakorn , Kota Sridhar
Published: June 2008

In this paper, we investigate power flow in compliant mechanisms that are employed in dynamic applications. More specifically, we identify various elements of the energy storage and transfer between the input, external load, and the strain energy stored within the compliant transmission. The goal is to design complaint mechanisms for dynamic applications by exploiting the inherent energy storage capability of compliant mechanisms in the most effective manner. We present a detailed case study on a flapping mechanism in which we compare the peak input power requirement in a rigid-body mechanism with attached springs versus a distributed compliant mechanism. Through this case study, we present two different approaches, (1) generative-load exploitation and (2) reactance cancellation, to describe the role of stored elastic energy in reducing the required input power. In contrast to a conventional mechanism with a spring, stress and strain in a compliant mechanism are more uniformly distributed. The entire mechanism stores energy rather than just a spring, providing more energy storage per unit mass. We propose a compliant flapping mechanism and its evaluation using nonlinear transient analysis. The input power requirement of the proposed compliant flapping mechanism is found to be 48% and 10% less than those of the four-bar flapping mechanism without and with a spring, respectively. The results show that a compliant mechanism can be a better alternative to a rigid-body mechanism with attached springs.
Synthesis of Planar, Shape-Changing Rigid-Body Mechanisms
Authors: Korte Brian M. , Murray Andrew P. , Schmiedeler James P.
Published: June 2008

This paper presents a procedure to synthesize planar linkages, composed of rigid links and revolute joints, capable of approximating a shape change defined by a set of curves. These “morphing curves” differ from each other by a combination of rigid-body displacement and shape change. Rigid link geometry is determined through analysis of piecewise linear curves to achieve shape-change approximation, and increasing the number of links improves the approximation. A mechanism is determined through connecting the rigid links into a single chain and adding dyads to eliminate degrees of freedom. The procedure is applied to two open-chain examples.
An Incremental Review Process for Requirements Verification
Authors: Lee David E.
Published: June 2008

An incremental review process for verification of requirements associated with spacecraft is described. Rather than wait for a final, cumulative top-down systems-level review to verify all requirements prior to pre-shipment of a spacecraft, a process has been developed that incrementally verifies requirements at multiple levels of allocation and builds a cumulative collection of verification data products. By reviewing and verifying requirements as early as possible, risks associated with verification are exposed and retired throughout design development and into early integration and test. Verification products such as detailed analyses and end item data packages are generated by the technical experts supporting the spacecraft development effort and are assessed against pertinent requirements to ensure their completeness for verification documentation purposes. The products submitted and approved for verification are tracked and stored in common access areas online to enable verification efforts to proceed across a flight program at multiple levels — subsystems, spacecraft, space segment and system — simultaneously. Thus, changes in personnel and staffing levels during the life of a flight program are managed by enabling assessment expertise to assess verification materials as soon as they are available — instead of waiting potentially for years to be reviewed and perhaps impacting spacecraft shipment and the launch schedule. Details of the Incremental Verification Review (IVR) process are discussed and application of the process to a flight program is presented.
Estimation of Target Selling Price in New Product Development
Authors: Minis Ioannis , Kourounis Taxiarchis C.
Published: June 2008

This paper proposes a systematic way of estimating the target selling price of a new product, at the early design stages of its development. The main objective of the method is to establish a robust price estimate strictly according to the market perspective. Based on concepts inspired by House of Quality, the proposed method uses the customer requirements (CR), as well as the perceived satisfaction of each CR, and estimates the selling price based on the price of competitive products. Using this price estimate and subtracting profit and overheads, the product target cost (material and labor) can be estimated, providing a critical input to the new product development team. The research focuses on simple assemblies, an area in which target costing is not yet widely used.
Hinged Beam Elements for the Topology Design of Compliant Mechanisms Using the Ground Structure Approach
Authors: Ramrkahyani Deepak S. , Frecker Mary I. , Lesieutre George A.
Published: June 2008

The design obtained from a topology optimization problem can largely depend on the type of the ground structure used. A new type of ground structure containing hinged beam elements is described in this paper that reduces the dependence of the optimal design on the ground structure. Apart from the beam and truss elements that have traditionally been used, two new types of elements are introduced: 1) a beam with a hinge on one end and a solid connection on the other end, 2) beam element with hinges on both ends. These elements are particularly useful when applied to a compliant mechanism design using a truss/beam type ground structure. A couple of compliant mechanism problems are solved to demonstrate the effectiveness of these elements.
Design of a 1.0mm Multifunctional Forceps-Scissors Instrument for Minimally Invasive Surgery
Authors: Aguirre Milton E. , Frecker Mary
Published: June 2008

A multifunctional forceps-scissors instrument is designed for minimally invasive surgery. The device is a compliant mechanism capable of both grasping and cutting. The focus of the paper is on the design optimization and a detailed finite element analysis of the compliant mechanism. One-half of the symmetric compliant mechanism is modeled as a cantilever beam of rectangular cross-section undergoing large deformation. The optimization problem is solved graphically where all feasible designs (i.e., those that satisfy the stress and geometric constraints) are displayed on performance space plots. Using this method it is easy to visualize the performance space and to select a suitable design; however, it is found that it is not possible to simultaneously maximize free deflection and blocked force in the forceps or scissors modes. A detailed finite element analysis was conducted using ANSYS to model the multiple loading conditions. A prototype instrument, fabricated from stainless steel using wire EDM with the precision of +/- 2 μm, has been tested for comparison of actual and predicted results.
An Analysis of Product Development Process Configurations Where an a Posteriori FE Criterion Improves Simulation Models Consistency
Authors: Ferrandes Rosalinda , Leon Jean-Claude , Marin Philippe , Giannini Franca
Published: June 2008

A mechanical behavioural analysis can be useful at different stages of the product development process, and there are different scenarios where a FE (Finite Element) analysis can support the design phase. Unfortunately, preparing a model suitable for the FE analysis and solving a FE problem are time expensive and need a considerable involvement of simulation experts. In this paper, we analyze several scenarios of product development process, where an a posteriori criterion allows exploiting some existing FE analysis results. Their common denominator stands in the evaluation of the impact of the component shape modifications on the accuracy of existing FE results, by means of an a posteriori FE error indicator. It is computed using the stress and strain fields over the component. This indicator is targeted to determine whether a shape sub-domain has some influence over pre-existing FE analysis results, i.e. whether an accurate FE analysis needs to use a model including this sub-domain. Here, we will describe the input and output parameters of our a posteriori indicator and what are the requirements for its incorporation in the different scenarios. Each of the proposed scenarios will be analyzed and illustrated to identify its potentials and requirements.
Designing Design Processes for Integrated Materials and Products Realization: A Multifunctional Energetic Structural Material Example
Authors: Panchal Jitesh H. , Choi Hae-Jin , Allen Janet K. , McDowell David L. , Mistree Farrokh
Published: June 2008

We present an approach for the integrated design of materials, products, and design processes. The approach is based on the use of reusable interaction patterns to model design processes, and the consideration of design process decisions using the value of information metrics. The approach is presented using a multifunctional energetic structural materials (MESM) design example. The design objectives in the example include sufficient strength and energy release capabilities. The design is carried out by using simulation models at different scales that model different aspects of the system. Preliminary results from the application of the approach to the MESM design problem are discussed. In this paper, we show that the integrated design of materials and products can be carried out more efficiently by considering the design of design processes.
Solid Powder Heating Process With Vaporization Modeling in the Warm-Up Stage of Process Chamber
Authors: Zheng Yunhan , Amano R. S.
Published: June 2008

Part accuracy and quality in rapid prototyping process using solid powder in the part cake are typically dependent upon thermal system and powder properties. The part cake is a rectangular mild steel cylinder with movable part plate piston. For maximum thermal stress reduction in the part-building process, about 1.27 cm or 2.54 cm initial solid powder was uniformly laid in the part cake. The powder was then warmed to a certain temperature before sintering. The amount of moisture present in the solid powder will have significant impact on the required warm-up time. In the moisture vaporization process, solid powder temperature in the computational cell will remain at 100°C until the moisture mass fraction reaches zero. The warm-up time of the cell will increase as the moisture content of the powder increases. Reference data has yet to be published on warm-up times, therefore machine operators will find variances in warm-up times. To better predict the warm-up time for the solid powder heating process with moisture vaporization in the warm-up stage of the part cake, a vaporization code model was developed that can also simulate the heating process with vaporization for any solid particle mixed with any liquid agent.
Description Logic Representation of Finite Element Analysis Models for Automated Retrieval
Authors: Udoyen Nsikan , Rosen David W.
Published: June 2008

Adaptive reuse of archived parametric finite element analysis (FEA) models to model similar, new problems is an important part of the process of learning to apply the finite element method to specific domains. Retrieval of relevant archived models and supporting documents from electronic repositories is difficult when a modeler is unable to describe information needs precisely in a query using keywords. The use of description logic concepts to describe archived models and build expandable classification hierarchies to facilitate retrieval is proposed and illustrated. A domain-independent retrieval algorithm based on the traversal of description logic concept hierarchies is introduced. Its usefulness is asserted by: • showing that intent behind FEA models can be represented precisely using a fairly inexpressive description logic; • showing that standard description logic inference supports retrieval of FEA models based on a modelers’ intent.
A Bayesian Approach to Reliability-Based Optimization With Incomplete Information
Authors: Gunawan Subroto , Papalambros Panos Y.
Published: June 2008

In engineering design, information regarding the uncertain variables or parameters is usually in the form of finite samples. Existing methods in optimal design under uncertainty cannot handle this form of incomplete information; they have to either discard some valuable information or postulate existence of additional information. In this article, we present a reliability-based optimization method that is applicable when information of the uncertain variables or parameters is in the form of both finite samples and probability distributions. The method adopts a Bayesian Binomial inference technique to estimate reliability, and uses this estimate to maximize the confidence that the design will meet or exceed a target reliability. The method produces a set of Pareto trade-off designs instead of a single design, reflecting the levels of confidence about a design’s reliability given certain incomplete information. As a demonstration, we apply the method to design an optimal piston-ring/cylinder-liner assembly under surface roughness uncertainty.
Investigation of Compliant Ortho-Planar Springs for Rotational Applications
Authors: Rasmussen Nathan O. , Todd Robert H. , Howell Larry L. , Magleby Spencer P.
Published: June 2008

This paper explores the feasibility of using compliant-ortho-planar springs (COPS) for rotational applications. The primary motivation is the application of COPS to a rubber v-belt continuously variable transmission (CVT). Although stresses and stress concentrations are important for the design of a COPS, this paper will focus on the behavior of a COPS resulting specifically from its rotation. This paper focuses on issues related to stress stiffening and lateral instability. Both phenomena are a direct result of the inertial loads a COPS would experience in a rotating environment. The results show how stress stiffening and lateral buckling are influenced by design parameters. Conclusions and recommendations for further research are presented.
Pseudo-Rigid-Body Model Chain Algorithm: Part 1 — Introduction and Concept Development
Authors: Pauly Joby , Midha Ashok
Published: June 2008

Pseudo-rigid-body models help expedite the compliant mechanism design process by aiding the analysis and synthesis of candidate design solutions, using loop-closure techniques for rigid-body mechanisms. Presently, these models are available only for relatively simple compliant beam geometries and loading situations. The chain algorithm is an alternate method for the design and analysis of compliant mechanisms. Though more versatile, insofar as the geometry and loading are concerned, it is not possible to implement this technique in analysis or synthesis problems involving loop-closure equations. This paper proposes the construction of a generalized “pseudo-rigid-body model chain;” it allows the use of pseudo-rigid-body models in conjunction with the chain algorithm to obtain the deformation kinematics of complex compliant members. Such a “pseudo-rigid-body model chain” would possess dual advantages of expediency of modeling through the use of pseudo-rigid-body representations of compliant segments, and the inherent flexibility of the chain algorithm to geometry and load boundary conditions. The proposed technique involves discretization of the planar continuum into initially straight, equal length compliant segments, whose deflections due to the applied load boundary conditions are then determined using appropriate pseudo-rigid-body models. Such a model could potentially be used in the solution of compliant mechanism design and analysis problems when coupled with the use of loop-closure equations.
Designing Adaptronical Components for Compensation of Static and Quasi-Static Loads
Authors: Fleischer Ju¨rgen , Kno¨del Andreas , Munzinger Christian , Weis Martin
Published: June 2008

The increasing interest in active solutions for the compensation of static and quasi-static displacements at tooling machines, like mechatronics and adaptronics for example, must be looked at with regard to high dynamics and accuracy. Mechatronical systems for the compensation of displacements allow for high manufacturing accuracy and at the same time high machine dynamics. The high system costs make an application in industrial environments impossible. Besides mechatronics the area of adaptronics shows a high potential for cost reduction and system integration with a comparable functionality. This article describes the compensation for piezoelectric transducer stacks in the static and quasi-static range in particular. The piezoelectric transducers stand out for their excellent properties as actuators such as positioning accuracy and dynamics. The multifunctional properties of piezoelectric transducers allow for the spatial and functional integration of sensor and actuator for the realization of active components. Due to a limited time constant for the use of piezoelectric transducers as sensor, static loads must be transformed into a dynamic input signal for the transducer. The interdisciplinary design of the overall system is of vital importance. It is described and discussed by the example of the realization of an adaptronic strut with controllable elongation for parallel kinematics and an adaptronic hydrostatic pressure pocket unit for an intelligent hydrostatic leveling system.
Pseudo-Rigid-Body Model Chain Algorithm: Part 2 — Equivalent Representations for Combined Load Boundary Conditions
Authors: Pauly Joby , Midha Ashok
Published: June 2008

Pseudo-rigid-body models help expedite the compliant mechanism design process by aiding the analysis and synthesis of candidate design solutions, using loop-closure techniques for rigid-body mechanisms. Presently, these models are available only for relatively simple compliant beam geometries and loading situations. The pseudo-rigid-body model chain algorithm provides reasonable approximations of the deformed shape of complex compliant members; however, it has one major limitation. The elastic deformation of each compliant segment under combined load boundary conditions is obtained by superposing the pseudo-rigid-body model displacements due to i) the force and ii) the moment loads, respectively. Hence, each segment needs to be characterized by two separate pseudo-rigid-body models in order to accurately determine its deformation kinematics. Such an idealization of compliant segments would present significant challenges when attempting to represent the pseudo-rigid-body model chain in vectorial form, as in planar vector loop-closure methods. Vectorial modeling would be possible if each flexible segment in the chain could be represented by an “equivalent pseudo-rigid-body model.” This paper proposes the concept of a rudimentary equivalent pseudo-rigid-body model to represent compliant segments with combined load boundary conditions in the pseudo-rigid-body model chain algorithm. Such a model may help overcome the difficulties confronted in the potential implementation of the pseudo-rigid-body model chain in planar vector loop-closure solution techniques.
A 3D Pseudo-Rigid-Body Model for Large Spatial Deflections of Rectangular Cantilever Beams
Authors: Rasmussen Nathan O. , Wittwer Jonathan W. , Todd Robert H. , Howell Larry L. , Magleby Spencer P.
Published: June 2008

The design of compliant mechanisms has been aided by the development of pseudo-rigid-body models to predict the motion of flexible members undergoing large displacements. Many of these models are based on the fact that the end of a cantilever beam follows a near-circular path when planar loads are applied. This paper shows that the application of 3-dimensional end-loading causes a beam to follow a near-spherical path, even for beams with non-circular cross-sections. A 3D pseudo-rigid-body model is presented that allows the motion of an end-loaded rectangular beam to be predicted using a rigid link and a spherical joint. Two sets of deflection limits for 0.5% error are presented and shown to be dependent upon the aspect ratio of the cross-section of the beam. The model has the potential for aiding in the design of spatial compliant mechanisms and analysis of planar compliant mechanisms undergoing large out-of-plane motions.
Concept Generation Algorithms for Repository-Based Early Design
Authors: Vucovich Jayson , Bhardwaj Nikhil , Ho Hoi-Hei (Terence) , Ramakrishna Manjeshwar , Thakur Mayur , Stone Robert
Published: June 2008

Modern product and engineering design research explores methods for formally generating design concepts from stored knowledge. We discuss a design methodology which utilizes archived design knowledge gained from product dissection to aid novice designers in developing new product designs. In this design paradigm, new designs are developed as a model of the product’s intended functionality, rather than a model of actual, physical components. This paper formulates an algorithm to automatically generate a set of components to instantiate such a functional model using archived design knowledge, which maps components to the functions they can satisfy and provides precedents for which components can be connected. In order to avoid generating an exponential number of instantiations, component failure data is leveraged to develop a dynamic programming algorithm. In addition, a method which uses this information to train a Hidden Markov Model is also developed. This Hidden Markov Model is consulted to generate a set of instantiations with low failure rates while avoiding exponential runtime.
Multiobjective Optimization for Integrated Tolerance Allocation and Fixture Layout Design in Multistation Assembly
Authors: Li Zhijun , Kokkolaras Michael , Izquierdo Luis E. , Hu S. Jack , Papalambros Panos Y.
Published: June 2008

Cost and product quality are significant attributes in manufacturing processes, such as multistation assembly. We use multiobjective optimization for integrated tolerance allocation and fixture layout design to address their interaction and to quantify tradeoffs among cost, product quality, and assembly process robustness. Design decisions relate to product tolerances, assembly process tolerances, and fixture locating positions. A nested optimization strategy is adopted, and the proposed methodology is demonstrated using a vehicle side frame assembly example. The obtained results provide evidence for the existence of tradeoffs, based on which we can identify critical quality and budget requirements.
A Method to Improve Platform Leveraging in a Market Segmentation Grid for an Existing Product Line
Authors: Farrell Ronald S. , Simpson Timothy W.
Published: June 2008

This paper describes a method for improving commonality in a highly customized low volume product line whose members were originally developed one-at-a-time to meet specific customer requirements. Rather than focusing on redesign of the entire product line, which can often be cost prohibitive, the method is part of a strategy to redesign a limited set of component parts that have the highest potential for cost savings. The method involves a four-step process: (1) determine an optimal component solution for each member artifact of an existing market segment grid, (2) test the feasibility of using each optimal component as a platform for the other artifacts, (3) formulate an optimization problem around the feasibility statistics whose solution is a product platform portfolio, and (4) solve the optimization problem for the minimum number of platforms that can adequately span the existing market segment grid. The proposed method is applied to an example involving the redesign of actuator mounting yokes for an existing set of valves that are used in nuclear power plants. The method shows promise for determining a product platform mix that maximizes commonality yet meets performance requirements.
The Rhode Island Nightclub Fire: Some Calculations Related to the Evolution of Fire and Smoke
Authors: Lilley David G.
Published: June 2008

The recent fire at a Rhode Island nightclub unfortunately made it very clear that catastrophic fires still occur, and that many people still don’t realize just how quickly a seemingly simple fire can grow rapidly into an inescapable furious inferno. Discussion centers on the rapidity of fire growth in many situations, how experiments and modeling have helped to characterize the events, and how the population at large still does not appreciate the immense fire dangers. The technical and scientific information about ignition, fire spread and analysis helps us to understand the amalgamation of key features of the incident. Calculations are shown of how the fire size, total evolution of smoke, smoke generation rate, and smoke level all vary with time, for situations of various rates of fire growth.
Investigating the Segmentation of Freeform Triangulated Surfaces Using a Self-Organizing Map
Authors: MacLennan Alexander D. , West Geoff , Cardew-Hall Michael
Published: June 2008

Freeform surfaces can be used to describe manufactured objects. These surfaces can be represented as point clouds, triangulated surfaces and range images. Before these objects can be analysed in any way they need to be broken down into their constituent parts. Using this description stamped parts can be indexed and retrieved to assist in determining how to manufacture a part that has similar properties. One means of performing this task is to segment the object based upon its surface properties. Curvature can be used to describe the behaviour of a surface. In order to use these metrics a single Self-Organizing Map is used to automatically categorise surface into regions of similar curvature. The SOM is first trained using a small number of simple shapes and curvature metrics. It is then used to segment an object that is a mixture of free form surfaces and planes. The combination of these metrics, shapes and the use of a SOM allows for the representation of many types of surfaces. The shapes and curvature metrics used to train the model determine how sensitive it is to different surface descriptions. This technique is successfully applied to a complex object that combines free form surfaces and planar surfaces using robust discrete curvature metrics.
A Critical Analysis of Description Logics for Engineering Information Management
Authors: Mocko Gregory , Rosen David W.
Published: June 2008

Engineering information management (EIM), specifically the development of information models, is becoming increasingly important to facilitate the exchange of digital product information across the extended enterprise. A myriad of information models has been proposed for capturing a broad scope of design information. Recently, description logics (DLs) have received significant attention in current literature as an underlying representational formalism for developing engineering information models. In this paper, we address the question: “Why should description logics (DLs) be used for engineering information management (EIM)?” We identify the characteristics of engineering design problems and the requirements for EIM, review common information modeling formalisms, and critically evaluate the benefits of DLs over other representational formalisms. The use of DLs is illustrated for modeling engineering decision information. Finally, it is argued that DLs provides several advantages over other modeling formalism, including Semantic Data Model (SDM) and Object-Oriented Data Model (OODM), through a logic-based representation that enables reasoning to be performed for checking the consistency of the information model and providing a means for organizing the information into a hierarchical taxonomy.
SHARP: A System for Haptic Assembly and Realistic Prototyping
Authors: Seth Abhishek , Su Hai-Jun , Vance Judy M.
Published: June 2008

Virtual Reality (VR) technology holds promise as a virtual prototyping tool for mechanical assembly; however, several developmental challenges still need to be addressed before virtual prototyping applications can successfully be integrated into the product realization process. This paper describes the development of SHARP (System for Haptic Assembly & Realistic Prototyping), a portable VR interface for virtual assembly. SHARP uses physically-based modeling for simulating realistic part-to-part and hand-to-part interactions in virtual environments. A dual handed haptic interface for realistic part interaction using the PHANToM® haptic devices is presented. The capability of creating subassemblies enhances the application’s ability to handle a wide variety of assembly scenarios. Swept volumes are implemented for addressing maintainability issues and a network module is added for communicating with different VR systems at dispersed geographic locations. Support for various types of VR systems allows an easy integration of SHARP into the product realization process resulting in faster product development, faster identification of assembly and design issues and a more efficient and less costly product design process.
Accelerating the Hyperbolic Display of Complex 2D Scenes Using the GPU
Authors: Bailey Mike , Gebbie Nick
Published: June 2008

Hyperbolic geometry is a useful visualization technique for displaying a large quantity of two dimensional data simultaneously. What distinguishes this technique is that one particular area can be displayed in full detail with all other areas displayed in lesser detail. In this way, the entire scene is still on the screen so that the entire set of relationships, as well as emergency indicators, can always be seen. But, because the hyperbolic transformation equation is non-linear, it cannot be placed in the standard graphics hardware 4x4 homogeneous matrix. Thus, using the hyperbolic transformation prevents full use of the graphics pipeline hardware, and drastically reduces interactive speed. This paper discusses a way to recoup this display performance by encoding the hyperbolic transform into an OpenGL vertex shader that resides on the graphics GPU hardware. In this way, the hyperbolic transform can still be used interactively, even for very complex 2D scenes.
Design Information Support Tool (DIST): Its Development and Effectiveness Investigation
Authors: Okudan Gu¨l E. , Ogot Madara , Rao Girish
Published: June 2008

A number of software tools exist to assist the designer during the design process. These include tools for solid modeling of components, programs for simulating complex systems, for generating machining code and so on. However, a closer examination reveals that most of these tools are of use in the later stages in the design process. Even though design activity analyses showed the initial phases of design to have the maximum impact on the successful design of a product, few tools exist to support the needs of the designer during these critical stages. This paper documents the development of a design support tool (DIST) based on an analysis of a collaborative design activity. Then, results of an experiment are shared, which was designed to investigate DIST’s effectiveness during conceptual design by novice designers.
Configurable Design Matrixes for Systems Engineering Applications
Authors: Johansson Olof , Krus Petter
Published: June 2008

This paper presents a formalized approach to specify and implement design matrix support for systems engineering applications that structure large and complex product models. Design matrixes can clearly visualize the relationships between large amounts of hierarchically structured engineering objects and higher level systems engineering design objects like requirements and functions in the product model. Examples of structures that can be lied out along the X and Y axis of a design matrix are stakeholder trees, requirement trees, function-means trees, product concept trees, and implementation trees. The cells of the design matrix visualize how corresponding objects at the axes relate to each other. One benefit with configurable design matrixes is that the information content and layout of a design matrix can be specified by a user, and all software implementation effort is handled automatically by a generic software framework that is included in the engineering application. The paper provides an overview of the theory behind a formal specification language for configurable design matrixes. It gives examples of design matrix specifications and screen shoots of instances of these design matrixes generated by a prototype engineering application called FMDesign. The examples of different types of design matrixes are taken from a aircraft product model of a small business jet. A formal software specification of the design matrix specification language and the example engineering application is provided in UML class diagrams.
An Efficient Algorithm for Vehicle Crashworthiness Design Via Crash Mode Matching
Authors: Hamza Karim , Saitou Kazuhiro
Published: June 2008

This paper presents an efficient algorithm for developing vehicle structures for crashworthiness, based on the analyses of crash mode, a history of the deformation of the different structural zones during a crash event. It emulates a process called crash mode matching where structural crashworthiness is improved by manually modifying the design until its crash mode matches the one the designers deem as optimal. Given an initial design and a desired crash mode, the algorithm iteratively finds a new design whose crash mode is increasingly closer to the desired one. At each iteration, a new design is chosen as the best among the normally distributed samples near the current design, whose mean and standard deviation are adjusted by a set of fuzzy rules. Each fuzzy rule encapsulates elementary knowledge of manual crash mode matching, as a mapping from the differences between the current and desired crash modes, to the changes in mean and standard deviation for sampling a sizing parameter in a structural zone. A case study on a vehicle frontal crash demonstrated the algorithm outperformed the conventional methods both in design quality and computational time.