bluuebunny/crossref_metadata_2025 huggingface dataset:
Assessing Maintenance Cost for Design or Re-Design of Complex Machinery
Authors: Butler Alley , Baldwin Dan , Kashyap Mohit
Published: June 2008

Maintenance costs are often significant for complex machinery, and organizations that are able to accurately assess maintenance costs for complex machinery can design or re-design the machinery to reduce maintenance expenses. This paper provides a review of relevant reliability theory to provide a background for model construction. The maintenance cost model is then developed from a probabilistic perspective, with a hierarchical breakdown of the complex machinery, and with consideration of the time value of money. A framework for the cost model is offered in which the cost of repair and preventative maintenance is considered along with the downtime costs for repair or preventative maintenance. As a proof of concept, maintenance costs for Ship Service Gas Turbine Generators (SSGTG) are developed from the Navy’s OARS (Open Architecture Retrieval System) data. Problems with data quality and heuristic adjustment of the data are discussed, recognizing that work is ongoing to improve the quality of the Navy’s maintenance data. Cognition Corporation’s Cost Advantage software is used for the modeling effort, providing an ability to focus on maintenance cost at any level of detail and to obtain cost roll up, as needed. Conclusions are drawn with respect to the modeling of maintenance costs for complex machinery.
A Rule Level Knowledge Management System for Knowledge Based Engineering Applications
Authors: Fan I.-S. , Li G. , Lagos-Hernandez M. , Bermell-Garci´a P. , Twelves M.
Published: June 2008

This paper reports on a system that has been developed to facilitate the structure and reuse of engineering rules (ERs) in Knowledge-Based Engineering (KBE) systems. The proposed structure for rule elements supports the traceability of knowledge sources as well as where the knowledge elements are used in KBE applications. This forms the infrastructure to systematically manage the use and reuse of knowledge and control the version and update of the rules when new knowledge is gained. Representing product knowledge in rules is a way to capture the know-why of the design by modelling the decisions involved in the design process. KBE has been used as the mechanism to deploy this knowledge. Although the KBE technology can support the management of this knowledge, the maintenance of the knowledge is often a neglected task. This leads to a number of practical difficulties in the large scale rollout of KBE applications. To design an improved KBE rules maintenance system, the research team developed a generic representation to unify the off-line storage of the IF, COND and CASE statements used in the ICAD Design Language. Additional data fields are defined to maintain the traceability of the origin and use of rules. This is implemented in a Microsoft Access database. The integration of this off-line rule repository with the ICAD KBE system is achieved and validated in an industrial application. The data structure defined and the implementation system is detailed in this paper.
Modeling and Analysis of Vehicle Transmissions in Modelica/Dymola Environment
Authors: Zhang Y. , Zou Z. , Chen X. , Zhang X. , Tobler W.
Published: June 2008

This paper presents a systematic model for the analysis of vehicle automatic transmissions. The characteristics of powertrain components are formulated either based on experimental data or by models in the Modelica/Dymola library. The integrated vehicle model is used to simulate the shift dynamics of vehicle transmissions and the overall vehicle performance under various operation conditions. Transient variables such as clutch apply pressure, transmission output torque, shift time, etc., and their influence on shift quality are quantitatively analyzed for various transmission shift processes based on model simulation. The simulation results demonstrate the effectiveness of the powertrain model as an analysis and calibration tool for the development of powertrain control systems.
Design Decision-Making in the Early Stages of Collaborative Engineering
Authors: Kimura I. , Grote K.-H.
Published: June 2008

Design activities are a series of decision-making, and important decision-making takes place often early in product development. However, uncertainty and imprecision exist in such design stages and make decision-making extremely difficult. Furthermore, as collaborative engineering emerges, it is hard to coordinate every project participant because of the differences in locations, disciplines, cultures and languages. In the early design cycle, therefore, two factors might improve to reach optimal decisions—making communication in a project team smoother and allowing all the members to evaluate designs with uncertainty and aggregate pieces of these evaluations as a whole. To address these two, the Internet-based collaboration tools, RP, VP and fuzzy analysis should be introduced to product development. In this study, these tools are analyzed and structured in product development so that decision-making in difficult situations is eased and product cost and quality are improved while time-to-market is shortened.
Identifying Variable Effects on the Dimensional Quality of Compliant Assembly, Using Computer Experiments
Authors: Dahlstro¨m Stefan , Hu S. Jack , So¨derberg Rikard
Published: June 2008

Compliant sheet metal assemblies are often used as support structures in automobiles, airplanes and appliances. These structures not only provide a metrology frame for other modules to be assembled, but also give the product its aesthetic form. For this reason, the dimension quality of the assemblies is a very important factor to control, in order to make sure that the product will function as planned and continuously keep the product cost low. The assembly is influenced by variations in the component parts and the assembly processes. Tolerance analysis, as conducted in most industries today, is normally based on the assumption of rigid parts and is thus not always valid for sheet metal assemblies, due to their compliance. This paper will present a method, based on finite element analysis (FEA) and design of computer experiments, of identifying the influence of input variables on the final geometry variation of the assembly. The influence and the interactions among the input variables are analyzed with a response model that has been constructed, using the simulation results. This response model could be used to identify the important variables that need to be controlled in assembly. An example application is included, in order to demonstrate the simulation model and response model construction. Analysis of the results from the simulations can facilitate the design of the assembly process, in order to control the dimensional quality of the product.
Reconstructing Freeform Surface With Parameterized Features
Authors: Song Y. , Vergeest J. S. M. , Horva´th I.
Published: June 2008

Reconstruction of freeform surfaces is a state-of-the-art topic in reverse engineering. In this paper, a method of reconstructing freeform faces with parameterized freeform features is proposed. By their definitions in 3-Dimensional (3-D) space, freeform feature templates are analyzed and parameterized by high-level parameters first. The proposed parameterization provides both interactive user control and automatic feature extraction. With such freeform features, the designer can reason about and operate high-level entities in freeform surfaces than basic geometric constituents. An optimization function based on Hausdorff-like shape distance measuring method is proposed and applied as the similarity measuring method between the digitalized model surface and the parameterized feature template according to different kinds of features. Considering the fitting procedure between digitalized model surface data and the freeform feature templates, optimizing strategies were studied and the influence of parameters in each feature representation was qualified especially for shape elimination features. The proposed method was tested by numerical experiments based on ACIS® and Open Inventor®, fitting errors were analyzed as well.
Analysis and Design of a Four-Bar Linkage Type of Vibratory Parts Feeder Driven by Piezoelectric Actuator
Authors: Ting Yung , Shin Min-Sheng , Chang Hong-Yuan
Published: June 2008

In this article, vibratory parts feeder widely used in industrial automation with the structure of a symmetric four-bar linkage mechanism driven by piezoelectric actuator is investigated. The dynamic modeling and simulation of the system as well as the driving controller are developed. Experiment is carried out to measure the practical acceleration and force of the vibratory platform. In comparison the experimental result with the analytical result, both outcomes are quite matched, which indicates their good accuracy. Driving control circuitry with feedback design is instrumental to provide steady output performance. Finally, optimum design to improve the transport speed and keep the parts in order is discussed.
Autogenetic Design Theory: An Approach to Optimise Both the Design Process and the Product
Authors: Vajna Sa´ndor , Clement Steffen , Jordan Andre´
Published: June 2008

The paper presents a new approach aiming at modeling and supporting the design activity as the substantial activity within the product development process. The Autogenetic Design Theory facilitates the integration of intuition, creativity and artificial intelligence into the conventional design process. To this end, a phase-like allocation of the design process is assumed as the essential structure and an evolutionary algorithm is integrated as the core facilitating purposeful searching and combining. Hence, the flow of the design process can be influenced as all requirements can be included and, on the other hand, intuition and creativity are ensured through the evolutionary algorithm. The example of the shift fork, which was described in the paper, shows how ADT can support variant design. Next steps will include the application of the ADT to the other types of design. The optimisation of the shift fork was the first step towards a computer-based implementation of the ADT.
Lifecycle-Based Product Design Using Global Optimization Methods Based on Hierarchical Genotype Representation of Alternatives and Constraints
Authors: Yoshimura Masataka , Izui Kazuhiro , Fukatani Kazuma
Published: June 2008

Development of products that thoroughly integrate lifecycle design factors requires the simultaneous clarification and evaluation of numerous design elements. When such product development problems are treated as design optimization problems, these elements are expressed by decision variables, constraint functions and objective functions. The existence of complex relationships among such design elements increases the difficulty of formulating the problem model and conducting straightforward searches for optimal solutions. This study presents a method for representing design alternatives that have subordinate relationships, using hierarchical genotypes. Constraint relationships of alternatives are clarified using constraint matrices which are also transformed to hierarchical genotypes. Furthermore, the efficiency of different genotype structures is compared using numerical experimentations. Based on the experimental results, a procedure for constructing optimal hierarchical genotypes is proposed.
Computational Geometric Modeling and Unfolding of 3-D Folded Structures
Authors: Liu Wei , Tai Kang
Published: June 2008

Due to environmental considerations, corrugated paperboard folded into appropriate 3-D structural shapes are increasingly being used as packaging cushions, as a substitute for those traditionally made of polymer foams. However, since paperboards are manufactured in the form of sheets, 3-D structures have to be created from these boards by folding. The design of the necessary flat layout pattern of a board that can be folded into a reasonably complex and intricate shape is a process requiring a lot of costly trial-and-error and creativity on the part of the designer. This paper describes a methodology developed to aid the designer by automatically and systematically generating many possible flat layouts that can be folded into a specified 3-D folded structure. The key to such a method is a computer representation of the topology/connectivity of the faces of the 3-D folded structure by a graph-theoretic model, and an algorithm to operate on this model to unfold and generate the geometry of the planar layout. The procedure is implemented on a computer and resulting flat layout designs have been generated for four example structures. Some of the issues concerning the types of folded structures that can and cannot be easily unfolded and the types of layouts that can and cannot be generated by the current methodology are discussed.
Reconfiguration of Kinematic Structure for Changing Motion Requirement Based on Reusability Evaluation in Lie Algebra
Authors: Tokunaga Hitoshi , Matsuki Norio , Imamura Satoshi , Tanaka Fumiki , Kishinami Takeshi
Published: June 2008

This paper presents a new method for adapting the existing manufacturing system for a requirement change, such as the change of a required motion task, by modifying its kinematic structure from the viewpoint of the degrees of freedom of the end effecter of the mechanism. In a previous report, the authors formulated the kinematic structure and motion task using Lie algebra. In this report, using these representations and their inclusion relations, the authors propose a method for evaluating the reusability of a kinematic structure for a newly specified motion task, and then propose a method for reconfiguring the mechanism in Lie algebra according to the result of the reusability evaluation. Finally, in order to evaluate the usefulness of the proposed method, it is applied to a kinematic design example of a mechanism.
Informing Design Using Data Mining Methods
Authors: Giess M. D. , Culley S. J. , Shepherd A.
Published: June 2008

Manufacturing processes produce a considerable amount of data as dimensions are measured, tests are performed and assembly checks are undertaken. Predominantly these data are used to inform and help improve the associated manufacturing processes and procedures. A variety of Knowledge Discovery techniques [1] have been introduced in the engineering field, most typically in areas with large quantities of data [2]. This paper describes research into the use of such techniques in the manufacture and assembly of large complex engineering products, an area which is characterised by low volume of data and dispersed databases. The developed methodology seeks to incorporate various approaches, with emphasis on using extracted knowledge to inform the implementation of subsequent techniques. This investigation centres on discovering and quantifying relationships between the various balance and vibration tests performed throughout assembly of gas turbine rotors, and to highlight critical parameters. Current assembly practices do not use forward prediction of test performance, and the first stages of this project aim to produce a model to enable this. The scope of this model will then be extended to feed this knowledge back to be used in the design and manufacture of future components.
Computational Recognition of Functional Parameters of Surfaces for the Kinematic Design of Window Regulator Systems
Authors: Fanghella Pietro , Galliani Guido , Mezzadra Matteo
Published: June 2008

The paper deals with the choice of the motion parameters for a window regulator system. This problem is affected by aesthetic, geometric and functional constraints. A geometric formulation of the topic is discussed in the first part of the paper: types of surfaces suitable to define proper motion parameter are systematically listed. Then, computational procedures for the best fit of given points to some of such surfaces are discussed in details. They are applied to two numerical examples, one of known mathematical properties, the second taken from a real design problem. In the second part of the paper further design constraints are introduced and the consequent computational procedures described. Finally three different design solutions for the real problem are presented and evaluated from an engineering point of view.
Finite Element Analysis in 3D Using the Penalty Boundary Method
Authors: Clark Brett W. , Anderson David C.
Published: June 2008

Traditional methods for applying boundary conditions in finite element analysis require the mesh to conform to the geometry boundaries. This in turn requires complex meshing algorithms for automated mesh generation from CAD geometry, particularly when using quadrilateral and hexahedral elements. The 3D extension of the penalty boundary method (PBM) is presented as a method that significantly reduces the time required generating finite element models because the mesh is not required to conform to the CAD geometry. The PBM employs penalty methods to apply boundary conditions on a simple, regular mesh. The PBM also eliminates discretization error because boundary conditions are applied using CAD geometry directly rather than an approximation of the geometry.
Counting Degrees of Freedom for Developable Be´zier Surface Design
Authors: Chu Chih-Hsing
Published: June 2008

This paper investigates the number of degrees of freedom for geometric design of developable Be´zier surfaces. The conditions for developability are derived geometrically from the de Casteljau algorithm and expressed as a set of equations that must be fulfilled by the Be´zier control points. This set of equations enables us to infer important properties of developable Be´zier patches that characterize the patch design and simplify its solution process. With one boundary curve freely specified in 3D space, five more degrees of freedom are available for the second boundary curve of the same degree. Imposing parametric or geometric continuities across the boundary of two adjacent developable Be´zier patches results in a composite developable Be´zier surface that has fewer degrees of freedom. This work provides the foundation for a systematic implementation of a computer-aided design system for developable Be´zier surfaces.
Multiattribute Decision Making Using Hypothetical Equivalents
Authors: See Tung-King , Lewis Kemper
Published: June 2008

In this paper, the problem of selecting from among a set of alternatives using multiple, potentially conflicting criteria is discussed. A number of approaches are commonly used to make these types of decisions in engineering design, including pair-wise comparisons, ranking methods, rating methods, weighted sum approaches, and strength of preferences methods. In this paper, we first demonstrate the theoretical and practical flaws with a number of these commonly employed methods. We then present a method based on the concept of hypothetical equivalents and expand the method to include hypothetical inequivalents. We demonstrate the strengths and weaknesses of the various decision making approaches using an aircraft selection problem. The design of a research laboratory is used to demonstrate the method of hypothetical equivalents further.
A Customer-Based Expected Utility Metric for Product Design Selection
Authors: Besharati B. , Azarm S. , Farhang-Mehr A.
Published: June 2008

The ability to select a design alternative, from a set of feasible alternatives, that is likely to meet customers’ and designer’s preferences and also account for uncertainties is vital to the success of a product design process. This paper presents a new metric, a Customer-based Expected Utility (CEU) metric, for product design selection that accounts for a range of attribute levels (i.e., the customer range) within which customers make purchase decisions. The metric also accounts for designer’s preferences and uncertainty in achieving a desired attribute level (or a combination of attribute levels). The application of the CEU metric is demonstrated by rank-ordering a set of design alternatives for a cordless power tool. Using this metric, design alternatives that fall outside the customer range will yield a relatively low CEU value, while among those that fall in the customer range, the alternatives with a higher value of the designer’s utility yield a higher value of the CEU metric.
A Grammar-Based Approach to Sheet Metal Design
Authors: Soman Aditya , Campbell Matthew
Published: June 2008

This paper involves the development, implementation and testing of a geometric representation scheme for building feasible sheet metal components. The approach taken here is based on prior shape grammar methods for engineering design. A series of seventeen grammar rules have been developed to represent a variety of cutting and bending operations that can be applied to sheet metal to construct feasible shapes. The implemented system has benefits as both a user interaction tool or as the basis for a computational design synthesis approach for designing sheet metal components. An example of a real component is shown as well as the method for invoking the sheet metal grammar to create this component.
A Knowledge-Based Approach to Spur Gear Fabrication in Precision Forging Process
Authors: Aziz El-Sayed , Chassapis C.
Published: June 2008

Designing forged gears with constrained involute tooth profile is a time-consuming activity with high costs due to the complexity in the plastic deformation, machine limitations, and trial-error iterative methods used to design dies and develop process conditions. Recently, knowledge-based systems are proving to be a powerful tool and a great potential for developing intelligent design support systems to improve quality of products and reduce costs by eliminating or minimizing many of the trail-error iterations involved in process design. This paper describes research work in developing a knowledge-based gear design and manufacturing system that assists des igners to reduce the time needed to design precision forged solid gears and provide detailed process specification along with the required process model implemented in it. The system integrates knowledge about all aspects of gear design and manufacturing and provides powerful reasoning and decision-making capabilities for reducing the time between detailed design and final production. Once the user specifies the basic design requirements, the system automatically carries out geometric calculations and strength analysis according to American Gear Manufacturers Association (AGMA) standards, power rating and Finite Element Analysis (FEA) based techniques. With a successful power rating achieved, the system automatically feeds input parameters into the GEARFORGING program and carries out process planning for the gear forging process. Estimation of the number of preforming stages required, generation of detail die drawings, geometric parameters, and estimation of forging load and energy requirements of the process are calculated based on available material design databases, knowledge-based rules and feature-level calculations. The system generates the whole forging process from the billet to the final gear product. The results have been compared with those available in the current literature and good agreement has been demonstrated.
Computer Implementation of an Improved Kutzbach-Gru¨bler Mobility Criterion
Authors: Aguilera Daniel , Rico Jose´ Mari´a , Gallardo Jaime
Published: June 2008

Recent results have shown that the application of group theory to the Euclidean group, E(3), and its subgroups yields a new and improved mobility criterion. Unlike the well known Kutzbach-Gru¨bler criterion, this improved mobility criterion yields correct results for both trivial and exceptional linkages. Unfortunately, this improved mobility criterion requires a little bit more than counting links and kinematic pairs. An important advance was made when it was proved that the improved mobility criterion, originally stated in a language of group theory and subsets and subgroups of the Euclidean group, E(3), can be translated into a language of the Lie algebra, e(3), of the Euclidean group, E(3), and its vector subspaces and its subalgebras. The language of the Lie algebra, e(3), is far simpler than the nonlinear language of the Euclidean group, E(3). Still, the computations required for the improved mobility criterion are more involved than those required for the Kutzbach-Gru¨bler criterion, and it might preclude the employment of the improved mobility criterion in prospective tasks such as the number synthesis of parallel and modular manipulators. This contribution dispels these doubts by showing that the improved criterion can be easily implemented by a simple computer program. Several examples are included.
Design of Hierarchic Platforms for Customizable Products
Authors: Hernandez Gabriel , Allen Janet K. , Mistree Farrokh
Published: June 2008

The objective in product platform design is to synthesize a set of components that will be shared by a number of product variants considering potential sacrifices in individual product performance that result from parts sharing. A good platform strategy should allow us to specify different levels of commonality for the various features and components of the product family in order to reduce the impact of commonality on performance. In this paper, we formulate the design of platforms for customizable products as a problem of optimization of access in a geometric space. This approach allows us to develop systematically hierarchic product platforms with multiple levels of commonality. We illustrate the proposed approach with a case example: the design of a product platform for a line of customizable electric motors.
Optimal Design Decisions in Product Portfolio Valuation
Authors: Georgiopoulos Panayotis , Fellini Ryan , Sasena Michael , Papalambros Panos Y.
Published: June 2008

Product portfolio valuation is a core business milestone in a firm’s product development process: Determine what will be the final value to the firm derived from allocating assets into an appropriate product mix. Optimal engineering design typically deals with determining the best product based on technological (and, occasionally, cost) requirements. Linking technological with business decisions allows the firm to follow a product valuation process that directly considers not only what assets to invest but also what are the appropriate physical properties of these assets. Thus, optimal designs are determined within a business context that maximizes the firm’s value. The article demonstrates how this integration can be accomplished analytically using a simple example in automotive product development.
A Genetic Algorithm Based Method for Product Family Design Optimization
Authors: D’Souza Brayan S. , Simpson Timothy W.
Published: June 2008

Increased commonality in a family of products can simplify manufacturing and reduce the associated costs and lead-times. There is a tradeoff, however, between commonality and individual product performance within a product family, and in this paper we introduce a genetic algorithm based method to help find an acceptable balance between commonality in the product family and desired performance of the individual products in the family. The method uses Design of Experiments to help screen unimportant factors and identify factors of interest to the product family and a multiobjective genetic algorithm, the non-dominated sorting genetic algorithm, to optimize the performance of the products in the resulting family. To demonstrate implementation of the proposed method, the design of a family of three General Aviation Aircraft is presented along with a product variety tradeoff study to determine the extent of the tradeoff between commonality and individual product performance within the aircraft family. The efficiency and effectiveness of the proposed method is illustrated by comparing the family of aircraft against individually optimized designs and designs obtained from an alternate gradient-based multiobjective optimization method.
Robust Design Through the Use of a Hybrid Genetic Algorithm
Authors: Hacker Kurt , Lewis Kemper
Published: June 2008

In this paper we present a hybrid optimization approach to perform robust design. The motivation for this work is the fact that many realistic engineering systems are mutimodal in nature with multiple local optima, and moreover may have one or more uncertain design parameters. The approach that is presented utilizes both local and global optimization algorithms to find good design points more efficiently than either could alone. The mean and variance of the objective function at a design point is calculated using Monte Carlo simulation and is used to drive the optimization process. To demonstrate the usefulness of this approach a case study is considered involving the design of a beam with dimensional uncertainty.
Nonlinear Kinematic Tolerance Analysis of Planar Higher Pairs
Authors: Kyung Min-Ho , Sacks Elisha
Published: June 2008

This paper presents a nonlinear kinematic tolerance analysis algorithm for higher pairs based on configuration space construction. The input is a pair of planar parts whose profiles consist of line and circle segments. Each part translates along a planar axis or rotates around an orthogonal axis. The part shapes and motion axes are parameterized by a vector of tolerance parameters with range limits. The algorithm constructs a generalized configuration space, called a contact zone, that bounds the worst-case kinematic variation over the tolerance parameter range. The zone specifies the variation of the pair at every configuration and in every operating mode. It reveals qualitative changes in kinematic function, such as jamming, that can be caused by parameter variations. Case studies show that the algorithm is more accurate and detects more failure modes than a prior algorithm that computes a linear approximation of the contact zone.
An Extensive Simplex Method Mapping the Global Feasibility
Authors: Zhu Liang , Kazmer David
Published: June 2008

Understanding the global feasibility of engineering decision-making problems is fundamental to the synthesis of rational engineering decisions. An Extensive Simplex Method is presented to solve the global feasibility for a linear decision model relating multiple decision variables to multiple performance measures, and constrained by corresponding limits. The developed algorithm effectively traverses all extreme points in the feasible space and establishes the graph structure reflecting the active constraints and their connectivity. The algorithm demarcates basic and nonbasic variables at each extreme point, which is exploited to traverse the active constraints and merge the degenerate extreme points. Finally, a random model generator is presented with the capability to control the matrix sparseness and the model degeneracy for an arbitrary number of decision variables and performance measures. The results indicate that all these model properties are significant factors affect the total number of extreme points, their connected graph, and the global feasibility.
Development of an Automatic Design and Optimization System for Industrial Silencers
Authors: Wong Lee Ming , Wang G. Gary , Friesen Charles , Foo Ken How , Pang Lucas
Published: June 2008

Current Computer Aided Design (CAD) technologies offer parametric design functions to allow users to easily change products’ configurations, shape and dimensions without reconstructing the entire product model. A programming tool that often comes with most CAD packages enables a designer to better control the parametric interface. However, these two functions focus on rapid production of computer models, which usually takes place after the product design is completed. The product design process, which has more significant influence on product life-cycle costs, is not fully supported. This paper proposes a systematic method in which a product design can be finalized and optimized through the interactions between 3-D solid modeling and customized cost / performance analysis. The entire optimal design process and generation of design deliverables is fully automated through interactive programming. In addition, an automatic design and optimization system for industrial silencers has been developed, which takes customers’ order from the Internet, sends the order to a CAD system, generates the optimal design, and sends back the design to the customer. The entire process takes only a few minutes. The proposition of integrating customized product life-cycle considerations with the model generation and optimization, as well as the developed silencer design system should be useful for other product designs.
Architectural Optimisation Using Real Options Theory and Dependency Structure Matrices
Authors: Sharman David M. , Yassine Ali A. , Carlile Paul
Published: June 2008

This paper outlines a methodology for optimising the multi-domain architecture of a relatively integrated system through an appropriate level of modularisation to maximise societal value created. This method is developed through the application of real options theory and the dependency structure matrix (DSM), and illustrated using a reference example of an industrial gas turbine.
Dynamic Analysis and Optimization of Tensioner in Automotive Serpentine Belt Drive Systems
Authors: Nouri Mostafa , Zu Jean W.
Published: June 2008

A design methodology is developed to achieve optimum design of tensioner in serpentine belt drive systems. System component responses to a harmonic excitation from the crankshaft are obtained analytically by using a complete multi-degree of freedom model and also in explicit expressions using an equivalent single-degree of freedom model. Sequential quadratic programming and Kuhn-Tucker methods are applied to obtain the optimum design of the system modeled as multi-degree of freedom and single-degree of freedom respectively, with the objective of minimizing the undesired vibration of system components. It is shown that system vibration behavior improves substantially by optimizing the design of tensioner device.
An Investigation of Nonlinearity of Reliability-Based Design Optimization Approaches
Authors: Choi Kyung K. , Youn Byeng D.
Published: June 2008

Deterministic optimum designs that are obtained without consideration of uncertainty could lead to unreliable designs, which call for a reliability approach to design optimization, using a Reliability-Based Design Optimization (RBDO) method. A typical RBDO process iteratively carries out a design optimization in an original random space (X-space) and reliability analysis in an independent and standard normal random space (U-space). This process requires numerous nonlinear mapping between X- and U-spaces for a various probability distributions. Therefore, the nonlinearity of RBDO problem will depend on the type of distribution of random parameters, since a transformation between X- and U-spaces introduces additional nonlinearity to reliability-based performance measures evaluated during the RBDO process. Evaluation of probabilistic constraints in RBDO can be carried out in two different ways: the Reliability Index Approach (RIA) and the Performance Measure Approach (PMA). Different reliability analysis approaches employed in RIA and PMA result in different behaviors of nonlinearity of RIA and PMA in the RBDO process. In this paper, it is shown that RIA becomes much more difficult to solve for non-normally distributed random parameters because of highly nonlinear transformations involved. However, PMA is rather independent of probability distributions because of little involvement of the nonlinear transformation.
Visualization of Multidimensional Design and Optimization Data Using Cloud Visualization
Authors: Eddy John , Lewis Kemper E.
Published: June 2008

As our ability to generate more and more data for increasingly large engineering models improves, the need for methods for managing that data becomes greater. Information management from a decision-making perspective involves being able to capture and represent significant information to a designer so that they can make effective and efficient decisions. However, most visualization techniques used in engineering, such as graphs and charts, are limited to two-dimensional representations and at most three-dimensional representations. In this paper, we present a new visualization technique to capture and represent engineering information in a multidimensional context. The new technique, Cloud Visualization, is based upon representing sets of points as clouds in both the design and performance spaces. The technique is applicable to both single and multiobjective optimization problems and the relevant issues with each type of problem are discussed. A multiobjective case study is presented to demonstrate the application and usefulness of the Cloud Visualization techniques.
Benefit Evaluation of New Technologies
Authors: Schabacker Michael
Published: June 2008

In business theory there are no suitable benefit evaluation procedures for new technologies (e.g. CAD/CAM systems, EDM/PDM systems) in product development. Another problem is the missing process orientation as well as an inadmissible mix of quantifiable and qualitative benefits (if they are not be even neglected). Hence, the results are difficult to comprehend ([Schabacker, 2001], [Bauer, 1995]).
Smart Assemblies for Robust Design: A Progress Report
Authors: Downey Kris , Parkinson Alan R. , Chase Kenneth W.
Published: June 2008

Research conducted over the past decade has resulted in a suite of methods for robust design which can be applied during different design stages. These methods focus on reducing the sensitivity of the design to variation without removing its causes. In this research we are investigating an additional and very powerful means for achieving robustness that complements the other methods developed to date. We have dubbed this area “smart assemblies.” A smart assembly has features, not otherwise required by the function of the design, which allow the design to absorb or cancel out the effects of variation. In this paper we report our results to date. We discuss the close connection between smart assembly design and exactly constrained design. We present the beginnings of a smart feature classification system, a preliminary methodology for smart assembly design, and a case study.
ModelAngelo: A Rapid Prototyping System for Polystyrene
Authors: Smaili Ahmad , Hemadeh Ramsey , Zeineddine Firas , Akle Barbar
Published: June 2008

This paper presents a new complete CAD-driven rapid prototyping system for polystyrene. ModelAngelo, as it is called, consists of six subsystems featuring hardware and software. The system utilizes a virtual 3D CAD model to produce a set of commands used to control a 5-axis CNC Machine to move a heated-wire tool into a block of polystyrene to form the desired surface. The ultimate goal of ModelAngelo is to reach the stage of “what you see is what you get”. An overview of ModelAngelo system is first presented followed by a detailed discussion of ModelAngeloSoftware. The various mechanical subsystems responsible for realizing the final product are then described. Advantages and disadvantages of several tooltip designs are discussed and the best solution is selected. The main features of the robotic arm, which carry the tooltip is also discussed in detail. Finally ModelAngelo controller that manages the interaction between software and hardware is briefly highlighted and possible applications of ModelAngelo are suggested.
Automatic Process Planning of a Multi-Axis Hybrid Manufacturing System
Authors: Ruan Jianzhong , Eiamsa-ard Kunnayut , Zhang Jun , Liou F. W.
Published: June 2008

With the integration of multi-axis layered manufacturing and material removal (machining) processes, a hybrid system has more capability and flexibility to build complicated geometry with a single setup. Process planning to integrate the two different processes is a key issue. In this paper, an algorithm of adaptive slicing for five-axis Laser Aided Manufacturing Process (LAMP) is summarized which can generate uniform- or non-uniform slices. In order to avoid interruption in the deposition process for one slice, a skeleton-based offset deposition tool-path method is used to generate continuous moving paths. A method to build a non uniform (thickness) layer which utilizes two processes is presented and an overall algorithm for integration is described. The newly developed algorithm implemented in the process planning helps the hybrid system build part more efficiently.
Computer-Aided Fixture Design Verification: Part II — Tolerance Analysis
Authors: Kang Y. , Rong Y. , Yang J. C.
Published: June 2008

Tolerance analysis is the most important issue in computer-aided fixture design (CAFD) since the primary task of fixturing is to ensure the quality of machining, and it is an important part in computer-aided fixture design verification (CAFDV). This study presents a new approach for fixture tolerance analysis that is more generalized and can be used to assign locator tolerances based on machining surface tolerance requirements. The tolerance analysis is also generalized to handle any type of fixture designs, workpieces, datum features, and machining feature tolerances. Locator tolerance assignment distributes tolerances to locators based on a sensitivity analysis.
Topology Optimization of Compliant Mechanisms Using Evolutionary Algorithm With Design Geometry Encoded as a Graph
Authors: Akhtar Shamim , Tai Kang , Prasad Jitendra
Published: June 2008

This paper describes an intuitive way of defining geometry design variables for solving structural topology optimization problems using an evolutionary algorithm (EA). The geometry representation scheme works by defining a skeleton which represents the underlying topology/connectivity of the continuum structure. As the effectiveness of any EA is highly dependent on the chromosome encoding of the design variables, the encoding used here is a graph which reflects this underlying topology so that the genetic crossover and mutation operators of the EA can recombine and preserve any desirable geometric characteristics through succeeding generations of the evolutionary process. The overall optimization procedure is applied to design a straight-line compliant mechanism : a large displacement flexural structure that generates a vertical straight line path at some point when given a horizontal straight line input displacement at another point.
Optimal Embedding in the Topology Design of Structures
Authors: Qian Zhongyan , Ananthasuresh G. K.
Published: June 2008

Extensive literature exists on the topology design of single-component structures while multi-component structural systems have received much less attention. In this paper, we present a technique for optimizing the topology of a structure that should be connected to one or more pre-designed components to maximize the stiffness of the overall assembly. We call it an embedding problem because pre-designed components are to be optimally positioned and oriented within a design region while the connecting structure’s topology is optimized simultaneously. Continuous design variables are used to vary the locations of the embedded objects smoothly along with the topology of the connecting structure in order to apply gradient-based optimization algorithms. A new material interpolation function on the basis of normal distribution function is used for this purpose. Optimality criteria method combined with the steepest descent method is used to minimize mean compliance to obtain the stiffest structure for a given volume of material. As a special case of this method, topology optimization of multi-component structural systems is also considered. Illustrative examples are presented.
Compliant Mechanism Design With Non-Linear Materials Using Topology Optimization
Authors: Jung Daeyoon , Gea Hae Chang
Published: June 2008

In this paper, compliant mechanism design with non-linear materials using topology optimization is presented. A general displacement functional with non-linear material model is used in the topology optimization formulation. Sensitivity analysis of this displacement functional is derived from the adjoint method. Optimal compliant mechanism examples for maximizing the mechanical advantage are presented and the effect of nonlinear material on the optimal design are considered.
Modeling of Hydraulic Hose Paths
Authors: Chipperfield Kurt A. , Vance Judy M.
Published: June 2008

Hydraulic hoses are key components used to transfer power in heavy industrial machinery. The routing of these hoses is currently performed late in the product design process because no accurate physical models of the hoses exist that allow designers to predict the path the hoses will follow when installed in the machine. Designers must either guess the path the hose will take based on prior experience or wait until the first product prototype is built in order to experiment with the hose routes. This paper describes the use of ADAMS, a commercially available dynamic modeling package, to predict hose paths. The hose path model was verified by comparing the predicted paths to the paths of real hoses.
Impact of Fixture Design Sheet Metal Assembly Variation
Authors: Camelio Jaime A. , Hu S. Jack , Ceglarek Dariusz J.
Published: June 2008

This paper presents a new fixture design methodology for sheet metal assembly processes. The proposed approach focuses on the impact of fixture position on the dimensional quality of sheet metal parts after assembly, considering part and tooling variation and assembly springback. The optimization algorithm combines finite element analysis and nonlinear programming methods to find the optimal fixture position such that the assembly variation is minimized. The optimal fixture design methodology enables to significantly reduce the assembly variation in the presence of part and tooling variation. A case study is presented to demonstrate the design procedure.
Tolerance Analysis of a Three-Hinge Door System
Authors: Zhang Xianmin , Erdman Arthur G. , Zhang Hong
Published: June 2008

Tolerance analysis for assembly of a three co-linear hinges door system is studied in this paper. An analysis model is developed, in which the typical alignment errors between the pins and cylinders are included. The successful assembly conditions are presented. Simulations are carried out based on the models and the Monte Carlo method that predict successful assembly. Analysis results show that the positioning error, the distance between the axis of the pin and surface of the leaf, the thickness of the leaf and the depth of the mortise are the top 3 sensitive input variables in the system.
Process Design for the Automation of Online-Consolidation Composite Fiber Placement
Authors: Sturges Robert H. , Moutran Serge , Abbott Mark W. , Lee Munki
Published: June 2008

The paper discusses three design aspects for the automation of online-consolidation composite fiber placement. This work includes a thermal study for the design of the end-effector heat source. A 6-dof robot articulates the end-effector for the appropriate tow placement. A new method is introduced to place the task in the workspace and to define dimensional characteristics for the products. A compliance model is then developed to insure the most accurate path planning in the absence of external position feedback means.
Forging a Geometric Link Between Function-Based Design and DfM
Authors: Verma Manish , Dong Hui , Wood William H.
Published: June 2008

Design for Manufacture (DfM) tends to explore only a small space of possible designs toward improving manufacturability. By focusing primarily on detailed geometry, DfM tends to recommend incremental changes. This paper presents a methodology that begins at the conceptual design stage, applying functional modeling to the generation of design configurations. These functional abstractions are merged with real part geometry toward generating potentially manufacturable design skeletons. The direct connection from function to manufacturable form afforded by this method allows the designer to make better-informed design decisions at the earliest stages of the design process.