bluuebunny/crossref_metadata_2025 huggingface dataset:
Embedded Real-Time Linux for Cable Robot Control
Authors: Proctor Frederick M. , Shackleford William P.
Published: June 2008

Linux is a version of the Unix operating system distributed according to the open source model. Programmers are free to adapt the source code for their purposes, but are required to make their modifications or enhancements available as open source software as well. This model has fostered the widespread adoption of Linux for typical Unix server and workstation roles, and also in more arcane applications such as embedded or real-time computing. Embedded applications typically run in small physical and computing footprints, usually without fragile peripherals like hard disk drives. Special configurations are required to support these limited environments. Real-time applications require guarantees that tasks will execute within their deadlines, something not possible in general with the normal Linux scheduler. Real-time extensions to Linux enable deterministic scheduling, at task periods at tens of microseconds. This paper describes embedded and real-time Linux, and an application for distributed control of a Stewart Platform cable robot. Special Linux configuration requirements are detailed, and the architecture for teleoperated control of the cable robot is presented, with emphasis on the resolved-rate control of the suspended platform.
An Approach for Generating Variational Geometry of a Pattern of Holes With Composite Positional Tolerances
Authors: Liu Y. S. , Gao S. M.
Published: June 2008

In most present CAD systems, the accurate geometry representation of a part is given but the tolerance is just a text attribute without semantics. It hampers the integration of CAD/CAM. In last two decades, much research has been conducted on computer aided tolerancing. And many approaches to generation of variational geometry for various kinds of features have been given. However how to generate the variational geometry of a pattern of holes (POH) is not well studied yet although a POH is one of the most widely-used features in mechanical design. Based on DOF, an approach is proposed for generating variational geometry of a POH with composite positional tolerance in this paper. First, the limitation conditions for variations of a POH are given. Second, the mathematical models of translational and rotational variations are systematically derived. Then the algorithm for generating variational geometry of a POH is given. At last the proposed approach has been implemented with Visual C++ based on the geometric modeling kernel ACIS5.0.
Applying Universal Linking of Engineering Objects in the Automotive Industry: Practical Aspects, Benefits, and Prototypes
Authors: Zimmermann Johann U. , Haasis Siegmar , van Houten Fred J. A. M.
Published: June 2008

The bi-directional communication of CAD programs with subsequent applications such as process planning remains a key challenge in design-for-the-lifecycle. While it seems sensible that individual applications use their own collection of feature types and thereby allow users to have their specific perspective of the product, it is still difficult to automatically close the gap between the variety of applications. Universal Linking of Engineering Objects (ULEO) targets this concern. It is general enough to facilitate informational integration of the applications along the process chain. This paper examines a number of scenarios for exploiting ULEO’s benefits in the field of automotive development and reports on the associated prototypical software implementations. Principle alternatives and technical aspects relevant for applying ULEO are discussed in some detail beforehand.
Conceptual Design of Tool Storage Based on the Divergent Tree Method
Authors: Zhao Yanwei , Wang Wanliang , Zhang Yingli , Wang Zhengchu
Published: June 2008

The divergent tree method was adopted in this paper, and an illustrative example of tool storage design in the machining center was given to describe the divergent thinking in the conceptual design process of mechanical products. Firstly general divergent tree method was applied to get various schemes of storage, then the primary schemes were achieved by using the measure of known characteristics, finally the excellent degree appraisal approach was applied to find out the optimum one. In addition, an intelligent computer aided conceptual design system of tool storage based on the divergent tree method and excellent degree appraisal approach was demonstrated in this paper.
Comparison of Gradient and Non Gradient Based Methods for Crash Optimisation
Authors: Morelle Patrick , Remouchamps Alain
Published: June 2008

The BOSS Quattro system (developed by Samtech s.a.) is an open architecture allowing to run various optimisation engines including gradient based methods (SQP, GCMMA, Conlin, MDAQ, ...), DOE and Response Surfaces, and Genetic Algorithms. This system has been used and various optimisation strategies compared for the resolution of non linear optimisation problems including crash worthiness and airbags opening simulation. Thanks to BOSS Quattro open architecture, using neutral or specific drivers so to read information from models, software like MADIMO, Pam Crash, LS-Dyna, but also NASTRAN, SAMCEF and Abaqus can been used in order to model the non linear behaviour of the optimised vehicles. One or several models were used and computation distributed by BOSS parallel architecture on network of workstations. Direct parallel mode can be used, or the tasks distributed on the network through a Task Manager like for example LSF. As a first example, the optimisation of a stiffened box is performed using one (dynamic) then two models (static but elasto-plastic/dynamic). The external software used are NASTRAN and ABAQUS. A second example deals with the optimisation of a Golf crash model using MADIMO to represent a sequence of events including opening of air bags. Mixed optimisation is performed using as design variables : the time to open a given airbag (continuous) or the type of wheel configuration (pure discrete variable). Constraints are related to safety of the passenger (sternum invasion, various criteria related to accelerations).
Performance Optimization of Extrusion Blow Molded Parts Using Fuzzy Neural-Taguchi Method and Genetic Algorithm
Authors: Yu Jyh-Cheng , Hung Tsung-Ren , Thibault Francis
Published: June 2008

This paper presents a soft computing strategy to determine the optimal die gap parison programming of extrusion blow molding process. The design objective is to minimize part weight subject to stress constraints. The finite-element software, BlowSim, is used to simulate the parison extrusion and the blow molding processes. However, the simulations are time consuming, and minimizing the number of simulation becomes an important issue. The proposed strategy, Fuzzy Neural-Taguchi and Genetic Algorithm (FUNTGA), first establishes a back propagation network using Taguchi’s experimental array to predict the relationship between design variables and response. Genetic algorithm is then applied to search for the optimum design of parison programming. As the number of training samples is greatly reduced due to the use of orthogonal arrays, the prediction accuracy of the neural network model is closely related to the distance between sampling points and the evolved designs. The Reliability Distance is proposed and introduced to genetic algorithm using fuzzy rules to modify the fitness function and thus improve search efficiency. This study uses ANSYS to find the stress distribution of blown parts under loads. The comparison of results demonstrates the effectiveness of the proposed strategy.
An Evolutionary Clustering Approach to Pareto Solutions in Multiobjective Optimization
Authors: Jeong Min Joong , Yoshimura Sinobu
Published: June 2008

Pareto solutions in multiobjective optimization are very problematic to measuring the characteristics of solutions for engineering design because of their considerable variety in function space and parameter space. To overcome these situations, a clustering-based interpretation process for Pareto solutions is considered. For better competitive clustering algorithm, we propose an evolutionary clustering algorithm — ECA. The ECA requires less computational effort, and overcomes local optimum of the K-means clustering algorithm and its related algorithms. Effectiveness of the method is examined in detail through the comparison with other algorithms.
Computer-Aided Analysis of Free Transverse-Vibration of Stepped Beams
Authors: Abhary Kazem , Nourbakhsh Ahmad
Published: June 2008

This method simulates a stepped beam by substructuring it into its n spans and treating each of which as a uniform continuous beam, clamped to its adjacent spans. Thus, at each step of the stepped beam, the two adjacent spans have identical displacements, slopes, bending moments and shearing forces. Theoretically speaking, these boundary conditions along with those of the extreme ends (total of 4n), when applied to the vibration equation of corresponding spans, generate a set of 4n simultaneous equations whose solution generates the natural frequencies of the stepped beam, as well as the constants of the vibration equation of all spans. The mathematical algorithm furnished herein degenerates the above-mentioned 4n simultaneous equations into groups of four at a time and solves them one after the other. The algorithm is programmed in VISUAL C++, and its accuracy is justified via application to a five-span stepped-beam.
Human Modelling: A Constraint-Based Feature Modelling Approach
Authors: Chang Terry K. K. , Ho Brian C. H. , Yuen M. M. F.
Published: June 2008

Constraint-based feature modelling is a promising approach for object modelling. During the feature creation and modification, the relationships between features are well described and maintained. This eliminates the tedious work for constructing a complex feature-based model and provides an efficient method for shape modification. However, most of the feature representation schemes cover only the regular object domain. The application in sculpture object domain has been put aside. In this paper, the constraint-based feature modelling approach for sculpture object such as human body will be introduced.
Analysis of Loads and Stresses for a Sewing Needle
Authors: Huang Yuan Mao
Published: June 2008

This study analyzes the loads of a needle by using singularity functions and determines the Von-Mises stresses to predict the failure modes of needles by using a personal computer. After principal stresses are calculated from the bending stress, compressive stress and shear stress, predicted failure modes of needles based on the Von-Mises stress coincide with practical existing failure modes reported by a manufacturer. These calculated stresses are also compared with the results obtained by using the software ABAQUS in the mainframe, and the deviation between the results calculated by these two methods is also investigated. Using this methodology can obtain loads, stresses and failure modes of a needle with acceptable accuracy while reducing the cost of using the commercial software in the mainframe.
Cross Model Shape Reuse: Copying and Pasting of Freeform Features
Authors: Wang Chengsheng , Vergeest Joris S. M. , Horva´th Imre , Dumitrescu Raluca , Wiegers Tjamme , Song Yu
Published: June 2008

This paper provides a systematic approach for copying and pasting of freeform features among existing models of design. Freeform feature as complex high-level shape entity enables a fast creation and modification of a geometric model in the context of both mechanical and aesthetic design. Copying and pasting of freeform feature can enhance not only the rapid shaping of the geometric model itself, but also the inheriting of design knowledge built in existing designs. In this paper definitions of freeform feature are reviewed and consummated. An analysis of parametric and topological relevancy of freeform feature is given in terms of copying operation and an elaboration of the reconstruction of freeform feature in a new geometric model regarding to pasting operation is presented. The reuse of freeform feature is discussed, and related algorithms are presented in detail.
A Stochastic Optimization Application for Vehicle Structures
Authors: Fu Yan , Wang Steve C. , Diwekar Urmila M. , Sahin Kemal H.
Published: June 2008

With the continuous improvement of powerful computers, vehicle structural designs have been addressed using computational methods, resulting in more efficient development of new vehicles. Most simulation-based optimization generates deterministic optimal designs without considering variability effects in modeling, simulation, and/or manufacturing. This paper presents an application of a new stochastic optimization method for vehicle side impact design. Nonlinear response surface models are employed for approximations of the side impact related test performance functions to conduct this study. The main goal is to maintain or enhance the vehicle side impact test performance while minimizing the vehicle weight under various uncertainties. The new algorithm alleviates the computational burden of excessive model evaluations by estimating the objective and constraint functions during the optimization process through a reweighting method. The efficiency and accuracy of this algorithm is presented through an actual vehicle safety design problem.
A Web Enabled Process for Accessing Customized Parametric Designs
Authors: Flores Rogelio , Jensen C. Greg , Shelley Jon
Published: June 2008

Parametric design facilitates mass customization, concurrent engineering, optimization, and other product development integration processes used during preliminary and detailed design stages. Automated methods for regenerating and accessing parametric models can significantly reduce the time-to-market of new products. Applications that automate this process have inherent limitations based on the available features in commercial CAD systems. New technologies such as the component technology, used in conjunction with parametric and Internet-based design can eliminate current limitations of CAD applications based on Application Programming Interfaces. Joint educational/industrial examples will be used to illustrate where limitations have been reached with custom CAD applications built on commercial systems lacking the component technology. Furthermore, the CAD Services framework for the development of CAD and Computer-aided Manufacturing/Engineering (CAM/CAE) applications using the component technology will be discussed.
Decomposition-Based Assembly Synthesis Based on Structural Stiffness Considerations
Authors: Lyu Naesung , Saitou Kazuhiro
Published: June 2008

This paper presents a method for systematically decomposes product geometry into a set of components considering the structural stiffness of the end product. A structure is represented a graph of its topology, and the optimal decomposition is obtained by combining FEM analyses with a Genetic Algorithm. As a case study, the side frame of a passenger car is decomposed for the minimum distortion of the front door panel geometry, where spot-welded joints are modeled as torsional springs. First, the rates of the torsional springs are treated as constant values obtained in the literature. Second, they are treated as design variables within realistic bounds. By allowing the change in the joint rates, it is demonstrated that the optimal decomposition can achieve the smaller distortion with less amount of joint stiffness (hence less welding spots), than the optimal decomposition with the typical joint rates available in the literature.
Control, Design and Error Variables in Decomposition of Design Optimization Problems
Authors: Escanaverino Jose Martinez , Llamos Soriz Jose A. , Garcia Toll Alejandra , Ortiz Cardenas Tania
Published: June 2008

A method for the rational choice of control, design and error variables in optimization problems is devised, based on the reduction of the maximum matching of the problem graph to the Dulmage-Mendelsohn canonical form. The method allows the designer to find with minimum effort appropriate sets of control, design and error variables that lead to an ultimate decomposition in design optimization problems of any dimension. In design automation, this procedure is useful as a rationale to plan manual interventions, where designers guide the process according to domain-specific knowledge. The proposed technique is rigorous and intuitive, thanks to the application of sound graph-theoretic concepts. A real-life example of mechanical engineering design shows the applicability of the method.
Adaptive-Agent Based Simulation Model to Study Diffusion of Eco-Innovation Strategies
Authors: Rai Rahul , Allada Venkat
Published: June 2008

The objective of this paper is to understand and study sustainable product development using a systems approach. This paper focuses on the development of the “Factor X” model to study diffusion of eco-innovation strategies. The concept of “Factor X” is qualitatively similar to the concepts of eco-efficiency and dematerialization with an added quantitative edge. It focuses on reducing the environmental impact of economic activities in quantitative terms such as reducing environmental impacts by a factor of 4 or factor of 10, etc. In the real world, artifacts interact with each other to form a web structure (known as artifact system (AS)), which has its own laws of evolution. We have implemented the “Factor X” framework through an adaptive agent based simulation (AABS) model to study the implications of different AS scenarios (achieved by setting system defining parameters) on the propagation and extent of diffusion of eco-innovation strategies.
A Quantitative Approach for Designing Multiple Product Platforms for an Evolving Portfolio of Products
Authors: Seepersad Carolyn Conner , Mistree Farrokh , Allen Janet K.
Published: June 2008

Product variety can be provided more efficiently and effectively by creating families of products based on product platforms. One of the major advantages of the development of product platforms is the facilitation of an overall product development strategy, and an important factor in product development is the evolution of a family of products, including addition and retirement of products as well as changing demand and associated production quantities. In this paper, we present a quantitative approach for designing multiple product platforms for an evolving family of products. The approach is based on the utility-based compromise Decision Support Problem—a multi-objective decision support model with an objective function derived from utility theory. With this approach, a designer can model and consider multiple factors that influence the embodiment of product platforms as well as non-deterministic evolution of a portfolio of products serviced by the product platforms. We apply this approach to an example study of a family of absorption chillers, designed for a variable marketplace. Our emphasis is on the approach rather than the results, per se.
Platform Selection Under Performance Loss Constraints in Optimal Design of Product Families
Authors: Fellini Ryan , Kokkolaras Michael , Papalambros Panos Y. , Perez-Duarte Alexis
Published: June 2008

Designing a family of product variants that share some components usually entails a performance loss relative to the individually optimized variants due to the commonality constraints. Choosing components for sharing may depend on what performance losses can be tolerated. This article presents a methodology for making commonality decisions while controlling individual performance losses. Previous work focused on evaluating individual performance losses due to pre-specified sharing. Trade-offs were identified for different platforms (i.e., the sets of components shared among products) by means of Pareto sets. In the present work an optimal design problem is formulated to choose product components to be shared without exceeding a user-specified performance loss tolerance. This enables the designer to control trade-offs and obtain optimal product family designs for different levels of performance losses in an attempt to maximize commonality. A family of automotive side frames is used to demonstrate the approach.
Inverse Parametric Modeling From Independently Generated Product Data Sets
Authors: Huang Zhengdong , Yip-Hoi Derek
Published: June 2008

Parametric modeling has become a widely accepted mechanism for generating data set variants for product families. These data sets that include geometric models and feature-based process plans are created by specifying values for parameters within feasible ranges specified as constraints in the definition. The ranges denote the extent or envelope of the product family. Increasingly, with globalization the inverse problem is becoming important. This takes independently generated product data sets that on observation belong to the same product family and creates a parametric model for that family. This problem is also of relevance to large companies where independent design teams may work on product variants without much collaboration only to attempt consolidation later on to optimize the design of manufacturing processes and systems. In this paper we present a methodology for generating a feature-based part family parametric model through merging independently generated product data sets. We assume that these data sets are feature-based with relationships such as precedences captured using graphs. Since there are typically numerous ways in which these data sets can be merged, we formulate this as an optimization problem and solve using the A* algorithm. The parameter ranges generated by this approach will be used to design appropriate Reconfigurable Machine Tools (RMTs) and systems (RMS) for manufacturing the resulting part family.
GA-Based Multi-Objective Fuzzy Matter-Element Optimization
Authors: Zhao Yanwei , Hua Ertian , Zhang Guoxian , Jin Fangshun
Published: June 2008

The solving strategy of GA-Based Multi-objective Fuzzy Matter-Element optimization is put forward in this paper to the kind of characters of product optimization such as multi-objective, fuzzy nature, indeterminacy, etc. Firstly, the model of multi-objective fuzzy matter-element optimization is created in this paper, and then it defines the matter-element weightily and changes solving multi-objective optimization into solving dependent function K(x) of the single objective optimization according to the optimization criterion. In addition, modified adaptive macro genetic algorithms (MAMGA) are adopted to solve the optimization problem. It emphatically modifies crossover and mutation operator. By the comparing MAMGA with adaptive macro genetic algorithms (AMGA), not only the optimization is a little better than the latter, but also it reaches the extent to which the effective iteration generation is 62.2% of simple genetic algorithms (SGA). Lastly, three optimization methods, namely fuzzy matter-element optimization, linearity weighted method and fuzzy optimization, are also compared. It certifies that this method is feasible and valid.
Parameter Sensitivity in System Identification of Parallel Mechanisms
Authors: Wiens Gloria J.
Published: June 2008

This paper presents a study on the sensitivity of the dynamics of parallel kinematic mechanisms (PKMs) and their effects on the system identification of inertial parameters. Comparing the sensitivity of the individual terms in the equations of motion, a delineation of areas prone to convergence errors in the presence of measurement noise and design parameter variations can be characterized. The design parameter variations evaluated were the strut masses, platform mass, joint location errors and friction. Comparative observations are made using sample trajectory based characterizations. Detailed results are presented for the University of Florida Special 6-6 PKM.
A New Symbolic Method to Determine Base Inertia Parameters for General Spatial Mechanisms
Authors: Chen Kaiyu , Beale David G.
Published: June 2008

Symbolic estimation of base inertia parameters is attractive. All published symbolic methods, however, are complicated and can only be applied to rotational joints and translational joints. This paper presents a new simple symbolic method to determine base inertia parameters for general mechanisms that include spherical joints and universal joints. The concepts of mass transfer and moment of inertia transfer are successfully extended to spatial joints and four propositions are developed based on the concepts. With the four propositions, a set of symbolic base parameters can be determined directly from the inspection of the joint configurations of general mechanisms. The determination of symbolic base inertia parameters of a spatial four bar mechanism is presented as an application example.
Development of an Interactive Web-Based Support System for Gear Design
Authors: Aziz El-Sayed , Chassapis C.
Published: June 2008

The Internet and World Wide Web (WWW) are now evolving as an important communication technology and a major information resource provider for industry. This paper discusses the development and implementation of a knowledge-based gear design and manufacturing system over the Internet to create new integrated design and manufacturing environments. By providing access to an interactive web-based support system, any designer with a WWW browser becomes a potential user of this on-line design system. Once connected, the designer follows the system instructions and submits the necessary input data on the appropriate web pages. The server receives a request from a client and invokes a CGI (Common Gateway Interface) program that processes the information provided through the user Interface. The CGI parses the data and has the ability to remotely run the knowledge-based gear design system that integrates knowledge about all aspects of gear design and manufacturing and provides powerful reasoning and decision-making capabilities for reducing the time between gear tooth creation, detailed design and manufacturing process specification via the Internet. When the execution is completed, full specifications definition, geometry, kinematic-loads and stresses are determined through Finite Element Analysis (FEA) within ANSYS, VRML models of the gear pair and gearbox assembly including gears, shafts, bearings and housing are exported according to the designer requests and sent back to designer on the web browser. To accomplish this, a combination of HTML, JavaScript, VRML, CGI Script and C++ is used. Finally, an example on spur gear design utilizing a parallel gearbox design model configuration is discussed.
Configurable and Extensible System for Experimenting With Design Optimization
Authors: Dickinson John K.
Published: June 2008

This paper outlines the need and describes the design of a modular software library and configurable and extensible framework built to support research into developing design automation techniques and methods for use during the early stages of design. Simple examples are provided to illustrate the extensibility and configurability of the complete system and a brief comparison of features is made with other existing systems. Lastly, a few preliminary results are provided to demonstrate the early potential of the system.
Hybrid Approach for Containment Problems
Authors: Yu Chan , Manoochehri Souran
Published: June 2008

A hybrid method combining a genetic algorithms based containment algorithm with a complex mating algorithm is presented. The approach uses mating between a pair of objects as means to accelerate the packaging process. In this study, mating between two objects has been defined as positioning one object relative to others by merging common features that are assigned through mating conditions between them. A constrained move set is derived from the mating condition that allows the transformation of a component in each mating pair to be fully or partially constrained with respect to the other. By using mating in the packaging, the number of components to be placed can be reduced significantly and overall speed of the packaging process can also be improved. The hybrid method uses a genetic algorithm to search mating pairs and global positions of selected objects. The mating pair is mated first by a simple mating condition which is derived from geometric features of mating objects. If a proper mating is not obtained, the complex mating algorithm finds an optimal mating condition using Quasi-Newton method.
New Concepts in Graphic Visualization of Objective Functions
Authors: Simionescu Petru-Aurelian , Beale David G.
Published: June 2008

A method of inspecting the design space of multivariable objective functions is proposed. By scanning 1 or 2 of the variables at a constant step while partially minimizing or maximizing the function with respect to the remaining variables, sets of points are generated that can be fiarther used in producing 2D or 3D diagrams. A number of examples are given for showing the usefialness of the method in studying the design space of objective functions and of the constraint activity. All graphs are produced with an in-house program that allows generation of logarithmically spaced level-curve diagrams and accurately truncating fimction surfaces over the z-axis at specified heights.
Uncertainty Analysis Using a Constraint Reliability Index
Authors: Lakshmipathy Ramesh , Krishnamurty Sundar
Published: June 2008

This work proposes an uncertainty metric to capture and encode parametric uncertainty information that will enable engineering decision analyst to combine and compute probabilities of expected outcomes through mathematical constructs of joint probability functions. Its integration in a mechanical design system can be expected to facilitate simulation-based design under uncertainty. Specifically, the proposed technique helps to study the impact of the probabilistic nature of the input design or state variables and by applying the concept of failure probability aims to generate the corresponding probabilistic information of the output performance function. This work is based on evaluating a series of probabilities that the output cannot exceed a certain value for a given perturbed value of the design point. In this context, this paper reviews the First Order Second Moment (FOSM) reliability theory where the random parameters influencing the design appear only through their means and co-variances. Building on these works, an alternate approach is presented taking into account the fact that the system output is all the more influenced by functional constraints in the system, which if ignored can lead to inaccurate or irrelevant error estimation and could seriously affect subsequent posterior decision analysis. This work includes a reliable and efficient error estimation procedure to identify design points that violate boundary conditions through methodical constraint evaluations and subsequent adjusting of output estimation values. The proposed method is illustrated with the aid of a constrained optimization case study and an I-beam design problem.
Math-Based Performance Evaluation of an Experimental Car: Frontal Impact Crashworthiness
Authors: Mayer Robert R. , Lin Chin-Hsu , Wang J. T.
Published: June 2008

This study used finite element models to assess potential benefits of selected unconventional features, implemented in an experimental car, for vehicle crashworthiness in frontal impact. These safety features include: structural energy-absorbing bumper, hood lockdown with optimized hood and extendable bumper. The A-pillar intrusion and the effective acceleration of the vehicle were used as the parameters for measuring frontal impact crashworthiness performance.
Investigation of Variation and Uncertainty in Six-Sigma
Authors: Kazmer David , Hatch David , Zhu Liang
Published: June 2008

Six Sigma is a widely used moniker to represent a set of design and manufacturing techniques, the aggregate of which should effectively improve quality and lower cost. Six Sigma implies that six standard deviations of performance should be maintained between the performance mean and the closest specification limit. When multiple performance attributes must be satisfied, aggregation techniques may be applied for evaluation and optimization. This paper evaluates two common aggregation techniques, the multi-process capability index and the process desirability index, and investigates their appropriateness relative to variation and uncertainty. These methods are applied to a data set for DVD manufacturing generated according to a Central Composite Design for 6 processing variables and 8 quality attributes. The results indicate that both indices may lead to erroneous design and manufacturing decisions with poor estimation of quality and cost.
An Automated Process Planning System Based on Genetic Algorithm and Simulated Annealing
Authors: Ma G. H. , Zhang F. , Zhang Y. F. , Nee A. Y. C.
Published: June 2008

The paper presents the development of a computer-aided process planning (CAPP) system based on Genetic Algorithm (GA) and Simulated Annealing (SA). The system employs an optimization modeling method that generates all the feasible operation-method alternatives. It also provides flexible optimization criteria that will satisfy the various needs from different job-shops and/or job-batches. Two search algorithms based on GA and SA respectively have been developed to solve the problem effectively. Also, the system provides manufacturability analysis function, which gives designers and job shop operators helpful information about the manufacturing.
A Case Study in Extended Value Engineering
Authors: Anderson R. , Sturges R.
Published: June 2008

Extended value engineering techniques provide an efficient, systematic approach to expose unnecessary costs, spur innovation, and direct efforts toward product and process improvement. Extended value engineering involves the comprehensive application of function diagramming, cost/cycle analysis, process diagramming, and competitive cost comparison. The application of these techniques to a mining equipment manufacturer, specifically to an ore haulage vehicle, is described in terms of cost reduction and manufacturing process improvement.
Tolerance Specification for Cost Reduction
Authors: Zhu Jianmin , Ting Kwun-Lon
Published: June 2008

The paper presents a novel optimal tolerance specification technique to minimize product cost. By introducing the properties of order statistics and the theory of tolerance limit to the traditional simulation method, a n dimensional tolerance search problem is transformed into a two dimensional one. The established tolerance limit inference method has the advantages of high efficiency for computation, robust for any distribution, and guaranteed confidence level compared with other tolerance specification methods. In addition, to obtain the optimal product cost, unlike most cost analysis models, the production yield level in the analysis is treated as an optimal variable instead of a constant. The approach is demonstrated by examples.
Matching Minimum Strain Energy Curves to B-Spline Curves for Thick Layer Manufacturing
Authors: Kooijman Adrie , Vergeest Joris S. M.
Published: June 2008

One of the key issues of thick layer manufacturing is matching the shape of the flexible cutting blade to the local surface curvature of the model to be created. In this paper we explore a method to find the best matching minimum strain energy (MSE) curve for a given B-spline curve. For this purpose we developed software to a) generate a dataset containing MSE curves for a range of settings of the cutting tool and b) find the best matching curve from this MSE dataset to the given target curve. Both the MSE and the target curves are represented as point sets, the target curves having a considerable higher point density than the curves in the MSE dataset. The best matching MSE curve is defined as the curve with the minimum directed Hausdorff distance to the target curve. It is found that despite the relative low density of the dataset, for several practical domains of target curve shape, a satisfying match can be found. Numerical results concerning the matching accuracy are presented.
Adaptive Ruled Layer Approximation and Slicing for 3D Rapid Prototyping
Authors: Koc Bahattin , Lee Yuan-Shin
Published: June 2008

This paper presents a new method of generating adaptive ruled layers for rapid prototyping of 3D complex parts. To increase the accuracy and reduce the build time, an adaptive ruled layer approximation of the Stereolithography (STL) models for rapid prototyping processes is presented. Surface errors are analyzed to find the maximum errors at different layers of RP parts. By finding the RP surface errors, adaptive ruled layers are generated from the STL models. Using the constructed ruled layers of the STL models, multi-axis material removal process is integrated with the traditional rapid prototyping process to achieve better surface accuracy and to reduce the total build time.
Simplified Method of Calculating Assembly Time
Authors: Prusak Zbigniew
Published: June 2008

This paper presents a simplified method for functional evaluation of parts and subsequent combination and elimination of parts with redundant and unnecessary functions. The method uses a simple spreadsheet-based tool that has proven to be an effective aid during design review and brainstorming sessions. Also presented is a simple method of initial assessment of manual assembly times. The assessment is performed by taking into account basic factors influencing part recognition, handling, manual assembly workspace and putting the parts together. Usefulness of both tools has been initially tested on a wide range of assembly configurations, from a variety of simple consumer goods to aerospace components. Both tools can also be presented as checklists thus having a ready-to-use cookbook appearance, which was particularly valued by manufacturing engineers making quick on-the-floor assessments.
Accessibility Driven Spatial Partitioning for Generating Sacrificial Multi-Piece Molds
Authors: Huang Jun , Gupta Satyandra K.
Published: June 2008

This paper describes an algorithm based on accessibility-driven partitioning approach to the design of sacrificial multi-piece molds. We construct gross shape of the mold by subtracting the part model from the mold enclosure and analyze its accessibility. The gross mold shape is partitioned using accessibility information. Each partitioning improves accessibility and we produce a set of mold components that are accessible and therefore can be produced using milling and drilling operations. Our approach has the following advantages. First, by using multi-piece molds we can create geometrically complex objects that are impossible to create using traditional two-piece molds. Second, we make use of sacrificial molds. Therefore, using multi-piece sacrificial molds, we can create parts that pose disassembly problems for permanent molds. Third, mold design steps are significantly automated in our methodology. Therefore, we can create the functional part from the CAD model of the part in a matter of hours and so our approach can be used in small batch manufacturing environments.
Modeling the Impact of Embedding Passives on Manufacturing System Performance
Authors: Chincholkar Mandar M. , Herrmann Jeffrey W.
Published: June 2008

With the miniaturization of electronic products, reducing the size of the printed circuit board that forms the backbone of the product is paramount. Embedding passive components, which otherwise occupy valuable “real estate” atop the printed circuit board, into the printed circuit board substrate itself is one way of achieving this objective. This first part of this paper examines the techniques and advantages of embedding passives. Embedding passives also affects manufacturing system performance, due to a change in the processing sequence and changes to the processing times at resources. The latter portion of this paper describes a design for production tool for understanding the impact of embedding passives on the performance of a manufacturing system.
Biomimetic Concept Generation Applied to Design for Remanufacture
Authors: Hacco E. , Shu L. H.
Published: June 2008

This paper applies a biomimetic design method to generate concepts for design that facilitates remanufacture. Biomimetic design fully or partially imitates or evokes some biological phenomenon. A method for identifying and using biological analogies for engineering problems was introduced in an earlier paper. This initial method was tested on an example in design for remanufacture. Here, the method is further developed and used to find more biomimetic solutions for the same problem in design for remanufacture. While the example problem is in remanufacture, the method can be used to develop biomimetic concepts for engineering design in general. The paper first summarizes previous efforts in developing and testing the biomimetic concept generation technique. Next described are the differences in the method that are used for this paper, including the increased importance of strategies to help identify promising analogies. Results of applying the modified method to design for remanufacture are documented.
Using Compliant Mechanisms to Improve Manufacturability in MEMS
Authors: Clements Kemeny Deanne , Howell Larry L. , Magleby Spencer P.
Published: June 2008

Micro-electro-mechanical systems (MEMS) consist of micro mechanisms integrated with electrical components. MEMS are often fabricated using a layered manufacturing approach with polysilicon. Because of certain challenges and constraints inherent in the manufacturing methods for MEMS, compliant mechanism technology is beneficial in designing these micro devices. This paper examines the interaction of compliant mechanisms (CMs) and MEMS in three areas: (1) the characteristics of CMs that make them attractive to use in MEMS, (2) the challenges presented to the use of CMs due to the manufacturing processes inherent in MEMS, and (3) performance-related design challenges with CMs and MEMS. These are critical areas of design when considering manufacturability in MEMS.
A Step Towards Automated Design of Multi-Piece Sacrificial Molds
Authors: Dhaliwal Savinder , Gupta Satyandra K. , Huang Jun , Kumar Malay
Published: June 2008

This paper describes a feature-based approach for design of multi-piece sacrificial molds. Our mold design algorithm consists of the following three steps. First, the desired gross mold shape is formed based on the feature-based description of the part geometry. Second, if the desired gross mold shape is not machinable as a single piece, the gross mold shape is decomposed into simpler geometric components to make sure that each component is manufacturable using 3-axis CNC machining. The decomposition is performed to ensure that each component is accessible to end-milling tools, and decomposed components can be assembled together to form the gross mold shape. Finally, assembly features are added to mold components to facilitate assembly of mold components and eliminate unnecessary degree of freedoms from the final mold assembly. We expect that our decomposition algorithm will provide a step towards the necessary foundations for automating the design of multi-piece mold and therefore will help in significantly reducing the mold design and manufacturing lead-time.
Some Problems of Design for Nano-Manufacturing: Present and Future Aspects
Authors: Bzymek Zbigniew M. , Jordan Eric
Published: June 2008

This presentation contains introductory information about the possibility of Design for Manufacturing (DFM) of nanomachines and nanomechanisms. Some consideration was also given to the Computer-Aided Design (CAD) of mechanical nanosystems. It was written with two goals in mind: first, in order to promote discussion and a deeper understanding of nanomanufacturing problems and to shed some light on these “nano” challenges. The object of the second goal was to assist manufacturing engineers in facing and understanding the problems, methods, and procedures for the Design For Manufacturing (DFM) of nanomachines.
Destructive Modeling by Volume Decomposition and Its Applications
Authors: Woo Yoonhwan , Lee Sang Hun
Published: June 2008

Adding simple volumes, which are often called primitives, is a natural way to construct complex solid models. Conversely, cell-based volume decomposition is the existing method to decompose a complex solid model into simpler volumes that are often the primitives used to create the model. One problem of this volume decomposition is that it generates a large number of cells, many of which are unnecessary for the decomposition. In this paper, a volume decomposition method that improves the performance by avoiding generating the unnecessary cells is presented. Some possible applications are also presented to attest the usefulness of this volume decomposition method.
Image Registration for Multimodal Inspection of Mechanical Parts
Authors: Wu Yanyan , Gong Chunhe
Published: June 2008

Image registration is the process of aligning the corresponding features of images in the same coordinate system. Multimodal registration has been widely used in medical imaging and geographic imaging. However, it has not been broadly applied in the inspection imaging of mechanical parts. Multimodal registration can improve inspection accuracy and quality by combining complementary inspection data from different inspection methods, or “modalities”. The research focus of this work is to develop a computational algorithm to register a CMM point cloud with a CT image in the 2-D (planar) domain. Dealing with outliers is the major concern for achieving required registration accuracy. Targeting solving this problem, a new registration metric is proposed in this work, which makes application of the traditional ICP (Iterative Closest Point) algorithm robust, by optimizing the search for closest points.
Automation of Process Planning for Rough Boring of Turned Components With Monotonic Internal Primary Features
Authors: Motipalli V. V. Satish K. , Krishnaswami Prakash
Published: June 2008

This paper describes a novel method for automated process planning from bar stock for rough boring of turned components with monotonic internal geometry. By focussing on a well-defined but substantial part family, we are able to achieve complete automation of all aspects of the process plan, including operations sequencing, parameter selection, NC code generation, etc. Thus, it becomes possible to go from design to NC code in a fully automated fashion. The focus on a tightly defined part family also results in very simple but robust automation algorithms. This is in contrast to much of the reported work on automated process planning, which generally target diverse part families, leading to complex algorithms that fall short of complete design-to-NC automation.
A New Strategy for Automating the Generation of Product Family Members and Artifacts Applied to an Aerospace Application
Authors: Roach Gregory M. , Cox Jordan J. , Young Jared M.
Published: June 2008

A major challenge in industry today is to reduce the cost and cycle time in product development while maintaining enough flexibility to adapt to changing markets. Businesses are requiring more and more flexibility in order to produce custom goods at low cost. A new strategy called the Product Design Generator is presented to provide flexible product platforms through an automated design process where product variation is built into the product development process and is achieved through scalable and in some instances modular parametric models for a given product platform embodiment. A case study of web-based Product Design Generator is presented. The axial turbine disk Product Design Generator demonstrated cycle time reduction from 500 man hours to 15 minutes. This new product development strategy has demonstrated the potential to provide engineers the ability to study more potential design solutions, reduce the number of opportunities to introduce error in the product development process, and allows companies to apply a consistent design process across the organization.