bluuebunny/crossref_metadata_2025 huggingface dataset:
Setting Target Product Requirements: Decision Analytic Approach
Authors: Takai Shun , Ishii Kosuke
Published: June 2008

This paper focuses on the second step of a three-step design concept selection procedure: (step 1) identification and structuring of customer needs and constraints, (step 2) setting target product requirements using decision analysis, and (step 3) design concept selection using target product requirements as selection criteria. Particularly, this paper models and analyzes a decision problem of setting target product requirements by utilizing an influence diagram and a decision tree. Once the target product requirements are identified, engineers evaluate different design concepts in terms of how each concept satisfies the target product requirements. The next generation linear particle accelerator serves as an illustrative example.
Assembleability Analysis Using GapSpace Model for 2D Mechanical Assembly
Authors: Zou Zhihua , Morse Edward P.
Published: June 2008

The most fundamental, and perhaps most important, task in tolerance analysis is to test whether or not the components with tolerances are actually able to fit together. This problem doesn’t get much explicit attention because it is implicitly included in current tolerance analysis methods. However, for complex assemblies, especially for over-constrained assemblies, the implicit assumptions of assembly may not be valid. This paper proposes an assembly model, called GapSpace, which can capture the necessary and sufficient conditions needed to execute assembleability analysis. Assembleability analyses for both nominal components and those with tolerances are presented using the GapSpace model. Both worst case and statistical analyses are performed. The model and its attendant solution methods are more suitable to GD&T tolerancing than traditional plus/minus tolerancing.
New Modules Launch Planning for Evolving Modular Product Families
Authors: Allada Venkat , Lan Jiang
Published: June 2008

This paper presents a systematic methodology to optimize the module instance configuration of an evolving product family (PF). The proposed methodology seeks to maximize the total profit of a PF for a given planning horizon by taking into account the interdependencies of modules at both the product level and the PF level. The module configuration optimization problem can be viewed as a stage-wise sequential decision process. Dynamic programming (DP) is suitable for modeling such problems. The DP-based methodology proposed in this paper breaks up the PF module instance configuration optimization problem into smaller DP optimization problems involving module groups based on the independence assumption of profit change due to the module replacement strategies. The aggregation concepts of independent module groups and module clusters are used to decrease the state space in the DP model. A module group is defined as a group of interacting modules linked by the replacement dependence relationships in a PF. A module cluster is defined as the modules within a module group that are strictly inter-dependent on each other in replacement actions. A DP model is established for each of the module groups to optimize the PF through individually optimizing the module configuration of the individual module groups. In the DP model, the time points with equal intervals during the planning horizon are considered as stages; the decision of module configuration strategies is defined as the control variable; the feasible combinations for the modules within one module group are selected as the states at each stage; and profit change (benchmarked with respect to profit without any module replacements) is treated as the contribution function that needs to be maximized. In the deterministic model, the expected change in profits and expected time of module instance availability are assumed to be deterministic. In the stochastic model, the profit change and the time of module instance availability are treated as uncertain events. The Monte Carlo method is used to simulate the total profit change distributions subjected to the uncertainties of data and module instance availabilities. We use an illustrative PF example to demonstrate how the suggested models can be used to optimize the PF architecture.
Design Evaluation of Multi-Station Assembly Processes by Using State Space Approach
Authors: Ding Yu , Ceglarek Dariusz , Shi Jianjun
Published: June 2008

This paper considers a problem of evaluating and benchmarking process design configuration in a multi-station assembly process. We focus on the unique challenges brought by the multi-station system: (1) a system level model to characterize the variation propagation in the entire process, (2) the necessity to describe the system response to variation inputs at both global (system level) and local (station level and single fixture level) scales. State space representation is employed to recursively describe the propagation of variation in such a multi-station process, incorporating process design information such as fixture locating layout at individual stations and station-to-station locating layout change. Following the sensitivity analysis in control theory, a group of hierarchical sensitivity indices is defined and expressed in terms of the system matrices in the state space model, which are determined by the given process design configuration. Implication of these indices with respect to variation control is discussed and a three-step procedure of applying the sensitivity indices to selecting a better design and prioritizing the critical station/fixture is presented. We illustrate the proposed method using the group of sensitivity indices in design evaluation of the assembly process of a SUV (Sport Utility Vehicle) side panel.
Square-IT and Plan-Merge: Decision Support Systems for High Quality Manufacturing Setup Sequences
Authors: Hayes Caroline C. , Pande Amit S.
Published: June 2008

Square-IT and Plan-Merge are software agents which assist in the process of creating manufacturing plans for small batch prismatic machined parts. Squaring is the process of generating a sequence of operations that prepares the stock so all surfaces are parallel or perpendicular to each other. Most automated process planning programs, and many machinists, perform squaring as a separate process completed prior to manufacturing the part. Although this practice simplifies planning, many opportunities for efficiency are lost when squaring and shaping the part into its final form are achieved in two completely separate plans. A far more efficient plan (i.e. fewer setups) can be achieved when squaring and feature cutting are treated as two types of operations included in a single, more globally efficient plan. Square-IT and Plan-Merge together perform this process of merging these two types of operations. The efficiency savings are dramatic. Setups can be reduced by 10 to 40 percent. Reducing set-ups also increases accuracy of the part by reducing opportunities for error. In future work we hope to adapt Square-IT and Plan-Merge so that they can be used as training tools that teach proper squaring and planning efficiency principles.
Observations on Raytheon 6 σ: The ASTOR Early Engagement
Authors: Treichler David H. , Carmichael Ronald
Published: June 2008

Raytheon Six Sigma (R6Sigma) is a six-step quality management approach and culture change effort that has proven to be highly effective. It incorporates lessons learned from the earlier efforts by Motorola, Texas Instruments, Allied Signal, General Electric, and many others. Within each of these major companies, the Six Sigma approach is a reflection of the company’s unique culture and specific industry needs. However, one criticism common to most of these programs is that the change analysis and leadership tools are engaged too late in the overall process. Building upon the lessons learned by other organizations, the paper recounts the early engagement of the Six Sigma tools, coupled with direct customer involvement, on a large-scale program by the Raytheon Company: The Airborne Stand-off Radar (ASTOR) system, which is under development for the UK Ministry of Defense (MOD). Because the ASTOR program is still years from completion, this paper cannot provide detail in terms of final lessons learned or quantified results derived from the front-end application of R6Sigma on this program. The purpose of this paper is to capture the thought processes behind (and initial stages observed during) early customer involvement and the application of R6Sigma process improvement approaches at the beginning of the program.
A Reverse Glue Approach to Automated Construction of Multi-Piece Molds
Authors: Chen Yong , Rosen David W.
Published: June 2008

Mold design can be a difficult, time-consuming process. Determining how to split a mold cavity into multiple mold pieces (e.g., core, cavity) manually can be a tedious process. This paper focuses on the mold construction step of the automated mold design process. By investigating glue operations and its relations with parting faces, an approach based on reverse glue operation is presented. The key of the reverse glue operation is to generate parting faces. A problem definition of parting face generation for a region is provided. Correspondingly, three face generating criteria are identified. Based on the parting lines of a region, our algorithms to generate the parting faces are presented. Our mold construction algorithms for two-piece molds and multi-piece molds are also presented with brief discussions. Some industrial examples are provided which illustrate the efficiency and effectiveness of our approach. We tested our mold designs by fabricating stereolithography mold inserts (a rapid tooling method) and molding parts.
Towards New Transitions Among Shape Representations
Authors: Vergeest Joris S. M. , Wang Chensheng , Song Yu , Spanjaard Sander
Published: June 2008

Four classes of shape representation are dominating nowadays in computer-supported design and modeling of products, (1) point clouds, (2) surface meshes, (3) solid/surface models and (4) design/styling models. To support applications such as high-level shape design, feature-based design, shape modeling, shape analysis, rapid prototyping, feature recognition and shape presentation, it is required that transitions among and within the four representation classes take place. Transitions from a “lower” representation class to “higher” class are far from trivial, and at the same time highly demanded for reverse design purposes. New methods and algorithms are needed to accomplish new transitions. A characterization of the four classes is presented, the most relevant transitions are reviewed and a relatively new transition, from point cloud directly to design/styling model is proposed and experimented. The importance of this transition for new methods of shape reuse and redesign is pointed out and demonstrated.
Feature-Based Part Similarity Assessment Method Using Convex Decomposition
Authors: Kim Yong Se , Jung Yong Hee , Kang Byung Gu , Rho Hyung Min
Published: June 2008

Mechanical parts are often grouped into part families based on the similarity of their shapes, to support efficient manufacturing process planning and design modification. This paper presents a similarity assessment technique to support part family classification for machined parts. It exploits the multiple feature decompositions obtained by the feature recognition method using convex decomposition. Convex decomposition provides a hierarchical volumetric representation of a part, organized in an outside-in hierarchy. It provides local accessibility directions, which supports abstract and qualitative similarity assessment. It is converted to a Form Feature Decomposition (FFD), which represents a part using form features intrinsic to the shape of the part. This supports abstract and qualitative similarity assessment using positive feature volumes. FFD is converted to Negative Feature Decomposition (NFD), which represents a part as a base component and negative machining features. This supports a detailed, quantitative similarity assessment technique that measures the similarity between machined parts and associated machining processes implied by two parts’ NFDs. Features of the NFD are organized into branch groups to capture the NFD hierarchy and feature interrelations. Branch groups of two parts’ NFDs are matched to obtain pairs, and then features within each pair of branch groups are compared, exploiting feature type, size, machining direction, and other information relevant to machining processes.
Feature Model for Surface Micro-Machined MEMS
Authors: Gao Feng , Hong Y. Steve , Sarma Radha
Published: June 2008

Lacking proper geometric design capability is one of the main factors that are impeding MEMS development. MEMS developers are suffering the cumbersome and unintuitive traditional design methodology in which the design of a new product begins with figuring out its fabrication mask layouts. As the kernel of new MEMS design methodology, a new model for MEMS devices is highly required to implement structured design strategies. This paper focuses on developing a feature model for MEMS geometric design, which enables designers to create fabrication-ready 3D models of MEMS devices in an intuitive manner. This feature model not only represents the geometric information of the devices but also provides the high level engineering means to describe the design intent, and hence, it can be used to facilitate the decision making process in design and the modification of models in subsequent stages. The separation of design and fabrication allows designers to concentrate on creative design activity without thinking of the tedious fabrication issues. The features specified according to common fabrication process aim to systematically map design intents to fabrication data. A generalized framework for MEMS feature model is presented in which the features are manipulated and managed in a declarative manner.
EMEDS: A System to Determine Ejection Layout for Rapid-Tooled Injection Molds
Authors: Jangha Sundiata K. , Rosen David W.
Published: June 2008

One of the main issues in injection molding is the amount of time required to design and fabricate a mold once a part representation has been created. Rapid tooling methods, the usage of rapid prototyping methods to fabricate molds, have been developed to speed up mold fabrication, but mold design time remains a bottleneck. The design of ejection mechanisms for rapid tools is investigated in this paper. By eliminating elements from a mold that are specific to the molded part, mold design time can be reduced. For instance, the use of a standardized ejector plate with an array of pre-drilled holes significantly reduces part specific elements from the ejector mechanism. The EMEDS system, Ejection Mechanism Design Synthesis, was developed to facilitate the rapid design and incorporation of ejection into rapid tools with standardized ejector plates. Problem formulations and solution algorithms will be presented for the two main elements of EMEDS, the Pin Composer and Pin Locator. In support of EMEDS, an analytical model of ejection force was developed and will be presented here. Application of the EMEDS system to an example illustrates the design of an ejection mechanism for an industrial part.
A Web Service Approach for Model Integration in Computational Design
Authors: Johansson Bjo¨rn , Krus Petter
Published: June 2008

When today’s engineering design process involves information generated by a wide range of computational tools it is necessary to find tools and methods to integrate this information efficiently. Recent advances in the standardization of distributed application development give new potential to deal with this issue. The programming interfaces made available for this communication are referred to as Web Services and implies a straightforward way to exchange design data between engineers, simulation tools and other distributed information resources. The paper illustrates how simulation models and tools can be deployed as web services and how functionality and design data can be exchanged between these tools and accessed from standard desktop applications. An integration framework is presented where distributed services are integrated and the computational process is explicitly defined and executed. This model integration service also enables design optimization using the COMPLEX algorithm and Monte-Carlo simulation for probabilistic analysis of the design. The presented framework is built on open standards and gives new potential to already existing tools. By wrapping computational tools into a web service they can be integrated and accessed by any other application supporting web-service communication regardless of computer platform or operating system.
A General Decision-Making Method for the Rapid Manufacturing of Customized Parts
Authors: Williams Christopher B. , Panchal Jitesh H. , Rosen David W.
Published: June 2008

In this paper we propose a general method for making process parameter decisions in the development of a rapid manufacturing system. Given a level of demand, the designer can use our method to select the appropriate type of rapid prototyping machine, the number of machines, the batch size, and other process parameters (layer thickness, road width, etc.) in order to achieve an ideal cost, throughput, and quality. We illustrate our method through the application of Stratasys’ Fused Deposition Modeling technology to rapidly manufacture customized hearing aid shells. We close with a look ahead to a larger problem: the use of our method to select the proper rapid prototyping technology for use in rapid manufacturing.
A Framework for Design Knowledge Reuse
Authors: Neelamkavil Joseph , Kernahan Michael
Published: June 2008

This paper details a framework for making design knowledge (process and product) available to the product development team by describing architecture and an application prototype for reusing design knowledge. The framework will allow designers to tap into manufacturing methods, engineering principles, company best practices, etc. that drive the design process. It enables the mapping of customer requirements to functional requirements and further mapping to components and assemblies, which ensures product traceability. It enables also to capture, archive and query a full range of design information, which help accelerating the design process. It utilizes past experience to guide designers on what to perform next.
Generic Sequential Sampling for Metamodel Approximations
Authors: Turner Cameron J. , Campbell Matthew I. , Crawford Richard H.
Published: June 2008

Metamodels approximate complex multivariate data sets from simulations and experiments. These data sets often are not based on an explicitly defined function. The resulting metamodel represents a complex system’s behavior for subsequent analysis or optimization. Often an exhaustive data search to obtain the data for the metamodel is impossible, so an intelligent sampling strategy is necessary. While multiple approaches have been advocated, the majority of these approaches were developed in support of a particular class of metamodel, known as a Kriging. A more generic, commonsense approach to this problem allows sequential sampling techniques to be applied to other types of metamodels. This research compares recent search techniques for Kriging metamodels with a generic, multi-criteria approach combined with a new type of B-spline metamodel. This Bspline metamodel is competitive with prior results obtained with a Kriging metamodel. Furthermore, the results of this research highlight several important features necessary for these techniques to be extended to more complex domains.
Characterizing Fine-Grained Associativity Gaps: A Preliminary Study of CAD-CAE Model Interoperability
Authors: Peak Russell S.
Published: June 2008

This paper describes an initial study towards characterizing model associativity gaps and other engineering interoperability problems. Drawing on over a decade of X-analysis integration (XAI) research and development, it uses the XAI multirepresentation architecture (MRA) as a means to decompose the problem and guide identification of potential key metrics. A few such metrics are highlighted from the aerospace industry. These include number of structural analysis users, number of analysis templates, and identification of computing environment components (e.g., number of CAD and CAE tools used in an example aerospace electronics design environment). One problem, denoted the fine-grained associativity gap, is highlighted in particular. Today such a gap in the CAD-CAE arena typically requires manual effort to connect an attribute in a design model (CAD) with attributes in one of its analysis models (CAE). This paper estimates that 1 million such gaps exist in the structural analysis of a complex product like an airframe. The labor cost alone to manually maintain such gaps likely runs in the tens of millions of dollars. Other associativity gap costs have yet to be estimated, including overand underdesign, lack of knowledge capture, and inconsistencies. Narrowing in on fundamental gaps like fine-grained associativity helps both to characterize the cost of today’s problems and to identify basic solution needs. Other studies are recommended to explore such facets further.
Flexible Concurrency Control for Synchronized Collaborative Design
Authors: Zhou Xun , Gao Shuming , Lie Jie , He Fazhi
Published: June 2008

Concurrency control is one of the most important and challenging issues in designing and implementing synchronized collaborative systems. Due to the complexity of collaborative design, the concurrency control in synchronized collaborative CAD systems is much more difficult. In this paper, the specific definitions of the concurrency conflict and intention preservation in the feature-based collaborative design are given. An approach to detecting the defined concurrency conflicts is also presented. Base on them, a prototype system of synchronized collaborative CAD is implemented.
Extensible Architecture for Geometric-Model Database Translation
Authors: Miller Perry L. , Oliver James H.
Published: June 2008

This paper introduces an extensible software architecture for geometric model translation based on the concept of “interface” querying. Translation occurs by instantiating a “source” and a “target” module which are able to determine each other’s capabilities by querying for necessary interfaces. Data transfer is initiated between these uncoupled modules using a neutral protocol that they agree upon. This dynamic interoperation continues until the transfer of information is complete. Since it does not require conformance to any specific set of geometric functionality, the architecture accommodates evolving geometric formats. Communication between decoupled modules exclusively through software interfaces facilitates the intended extensibility. In support of ongoing virtual prototyping research at the Virtual Reality Applications Center (VRAC), an example implementation of the architecture in software is presented for conversion of 3D models from a proprietary large model visualization format, EDS/PLM DirectModel, into several alternative formats.
Transient Analysis of Heated Vapor Extraction System for Effective Remediation
Authors: Jadhav R. S. , Amano R. S. , Jatkar J. , Lind R. J.
Published: June 2008

A soil remediation process has gained an enormous attention for the last decade in order to make the surroundings environmentally friendly. The areas around chemical companies or waste disposal sites have been seriously contaminated from the chemicals and other polluting materials that are disposed off. Different soil remedial processes are used for different types of pollutants. The present research effort is concentrated on modeling the Heated Vapor Extraction System, which is a very efficient and cost effective process. A numerical model is developed and Finite Volume Method is used to solve the model. The analysis uses the species transport and discrete phase modeling to predict the time required to clean the soil under specific conditions. The analysis was used as a mathematical computational tool to predict various parameters for the process so that the process can be made more efficient and effective in remedial achievements.
Experimental and Numerical Study in Thermal Design and Characteristics of Thermal Distribution in the Process Chamber
Authors: Zheng Y. H. , Amano R. S.
Published: June 2008

Thermal distribution has a critical effect on prototyping accuracy in rapid prototyping and rapid manufacturing. Any uneven thermal distribution in the work bed of the prototyping machine process chamber will result in product distortion. In order to optimize the thermal distribution enhance product accuracy of product and guide future design efforts, a full understanding is necessary, of the characteristics of thermal distribution in the process chamber. This study will focus on how to design and control thermal distribution in the process chamber due to natural convection with experimental and numerical thermal model. For optimal thermal design, the computational fluid mechanics (CFD) approach is one of the most powerful tools. Both experimental and numerical studies of six design configurations for different source heater locations and baffle configurations are presented in this paper.
Multi-to-One Cell-Matching Method and Its Application in VOF Interface Tracking
Authors: Xiao Yumin , Bayyuk Sami , Amano R. S. , Xie Jianhui
Published: June 2008

A new algorithm—multi-to-one cell matching method for interface tracking in volume-of-fluid (VOF) calculation is presented. This method is based upon unstructured grid and implemented on cells having quadrilaterals or hexahedrons origin. This method utilizes the geometrical characteristic of each vertex in an arbitrary cell to classify the vertex type and to group faces into four (two dimensional) or six (three dimensional) groups. The final regrouped arbitrary cells have the similar geometric information and VOF distributions as that of quadrilaterals or hexahedrons. Convective flux to solve the volume evolution equation can then be exactly evaluated. The method will enable the CFD-ACE+ to be implemented on unstructured adaptive mesh for VOF simulation. Numerical results for those test problems provide evidence for the algorithm’s quality, and accuracy.
Energy Efficiency, Air Quality, and Comfort in Air-Conditioned Spaces
Authors: Kameel Ramiz , Khalil Essam E.
Published: June 2008

To design an optimum HVAC airside system that provides comfort and air quality in the air-conditioned spaces with efficient energy consumption is a great challenge. This paper evaluates recent progresses of HVAC airside design for the airconditioned spaces. The present evaluation study defines the current status, future requirements, and expectations. It has been found that, the experimental investigations should be considered in the new trend of studies, not to validate the numerical tools only, but also to provide a complete database of the airflow characteristics in the air-conditioned spaces. Based on this analysis and the vast progress of computers and associated software, the artificial intelligent technique will be a competitor candidate to the experimental and numerical techniques. Finally, the researches that relate between the different designs of the HVAC systems and energy consumption should concern with the optimization of airside design as the expected target to enhance the indoor environment.
Co-Design of AZIMUT: A Multi-Modal Robotic Platform
Authors: Michaud Franc¸ois , Arsenault Martin , Bergeron Yann , Cadrin Richard , Gagnon Fre´de´ric , Legault Marc-Antoine , Millette Mathieu , Pare´ Jean-Franc¸ois , Tremblay Marie-Christine , Le´tourneau Dominic , Lepage Pierre , Morin Yan , Caron Serge , Bisson Jonathan
Published: June 2008

AZIMUT is a mobile robotic platform that combines wheels, legs and tracks to move in three-dimensional environments. Its design is the result of an interdisciplinary effort combining expertise in mechanical engineering, electrical engineering, computer engineering and industrial design. After presenting AZIMUT, this paper describes the challenges of designing such a robot, outlining the interdependencies between the disciplines and the difficult compromises that have to be made during the iterative design process of a mobile robotic platform. Modularity at the structural, hardware and embedded software levels, all considered concurrently in an iterative design process, reveals to be key in the design of sophisticated mobile robotic platforms.
Design Architecture of a Data Driven Environment for Multiphysics Applications
Authors: Michopoulos J. , Tsompanopoulou P. , Houstis E. , Rice J. , Farhat C. , Lesoinne M. , Lechenault F.
Published: June 2008

The design architecture of a multidisciplinary problem-solving environment (MPSE) for supporting an efficient prediction capability for the response of continuous interacting systems under multiphysics conditions is presented. The system will be referred to as a Data Driven Environment for Multiphysics Applications (DDEMA) and will be primarily differentiated from previous MPSE efforts on its usage of data for improved confidence of simulation prediction. Its architecture takes into consideration information technologies, coupled multiphysics sciences, and data-driven practices to achieve steering of adaptive modeling and simulation of the underlying systemic behavior. Special emphasis is given on middleware implementation issues based on actor-agent abstractions. A description of the design objectives and architectural variations of DDEMA are also given in the context of two multidisciplinary applications related to material/structure design of supersonic platforms and fire/material/environment interaction monitoring, assessment and management. Validation of the architecture will also be attempted in terms of the same two applications.
Cooperative Scheduling for Inter-Enterprise Manufacturing Resources Sharing
Authors: Hao Qi , Shen Weiming , Wang Lihui , Lang Sherman
Published: June 2008

This paper presents a cooperative virtual enterprise approach targeting the manufacturing resource sharing among small and medium enterprises. With intelligent agents and Web Services technologies being adopted, the proposed approach possesses a number of distinguishing characteristics, such as loosely-coupled distributed architecture, internal privacy protection, secure separation of information and autonomous operation. An enterprise model, partner search and selection mechanisms, coordination modes and operation monitoring mechanisms are presented in details. The proposed approach emphasizes the enterprise to maximize its profitability, which is always regarded as a higher priority over other concerns.
Engineering Portal for Collaborative Product Development
Authors: Yang Zhixin , Liu Zhejie , Zhao Jinmin , Shen Zhenqun , Xie Zhao , Liu Qinghong
Published: June 2008

The product development processes nowadays are featured with ever-increasing complexity of product configurations, diverse data resources, and multi-disciplinary, geographical dispersed engineering teams, and intensive use of various software tools for managing the data associated with the product and its life cycle. These characteristics result in the need of a collaborative product development (CPD) environment for today’s industries. This paper describes the methodology which enables the engineering collaboration within a compressed product development cycle, and presents our results with the development of a CPD environment. A four-tiered client/server collaboration architecture, which allows system integration, data sharing, and collaboration among team members in an internet platform, is described. By integrating the distributed application servers, such as product specification server, CAD/CAE server, project management, collaborative visualization workspace, and product data management module, using web technologies, an engineering CPD portal is proposed and implemented. This portal environment could bring entire engineering team together in one place in real-time, irrespective of geography, enterprise boundaries, or native systems, to share product information throughout the product development processes, which include product definition, design, engineering analysis, and manufacturing, etc. Manufacturing companies could therefore collaborate closely with their suppliers/collaborators global widely. A case study is carried out for collaborative development of a typical component used in data storage industry, the spindle motor, to illustrate the proposed approach and to validate the developed systems.
Business-to-Business Virtual Collaboration of Aircraft Engine Combustor Design
Authors: Kao Kevin J. , Seeley Charles E. , Yin Su , Kolonay Raymond M. , Rus Tony , Paradis Mike
Published: June 2008

In today’s fast-changing economy, product designs are becoming increasingly complex while demands for faster design cycles never cease. Tighter collaboration among business partners and streamlined integration of engineering processes have become a dominating factor in expediting time to market and succeeding in the competitive global environment. With modern computer-aided design/engineering solutions and revolutionary Internet technologies, such realtime business-to-business (B2B) design collaboration becomes a reality. This paper discusses various emerging technologies that enable a true B2B virtual collaboration of aircraft engine combustor design between GE Aircraft Engines — a jet engine manufacturer, and Parker Hannifin — a gas turbine fuel nozzle supplier. A case study involving the collaborative design and analysis of a fuel nozzle is also presented which demonstrates the realistic implementation of these new technologies.
Co-Evolutionary Ant Algorithm and Application in Multi-Objective Optimization Problems
Authors: Xiao Renbin , Tao Zhenwu
Published: June 2008

Inspired by the ideas of co-evolution of natural and artificial systems, we present the Co-evolutionary Ant Algorithm. The improved algorithm can weaken the contradiction between premature and converging efficiency, and is more convenient to use by the adaptive adjustment of the controlling parameters. We give the procedure of Co-evolutionary Ant Colony System (CoeACS) to settle Traveling Salesman Problem (TSP), a classical combinatorial optimization problem. The analysis of the computational complexity of CoeACS shows that this improved algorithm will not increase the complexity. This paper applies the CoeACS to the problem of the path planning of rock-drilling machine that can be viewed as a typical multi-objective optimization problem in discrete space, and the results validates the effectiveness of the improved algorithmic model.
Comprehending a Hand Motion Language in Shape Conceptualization
Authors: Horva´th Imre , Tromp Nynke , Daalhuizen Jaap
Published: June 2008

This paper reports on a study concerning the comprehension of an experimental hand motion language in shape conceptualization. Hand motion is regarded as a prospective input mechanism for computer aided conceptual design systems for initial shape design of consumer durables. Our hand motion language has been developed based on the analysis of the (a) information necessary to describe shape concepts, (b) descriptive and indicative capabilities of human hands, and (c) cognitive and perceptive aspects of processing hand motions. This language was used in designed experiments to describe simple, compound and hybrid shapes for designers and tested with respect to comprehensibility. The subjects were asked to reconstruct the presented shapes by sketching on paper. Comprehension of the hand motion language has been evaluated in terms of fidelity and efficiency. Fidelity was expressed in terms of the number of deviations of the sketches of the test shapes from the existing CAD models. Efficiency was expressed as the proportion of the time needed to understand the test shapes communicated by hand motions and the time needed for the presentation. The results clearly indicate the potentials of a HML in shape conceptualization. In addition, the experiments revealed several new issues related to the application of the hand motion language in a multi-modal interface. The most important one is the need of chunking of the hand motion sequences in a way that enables the computer system to reliably reconstruct shapes and the designers to understand the formation of shapes on a higher semantic level. These issues will be addressed in our future research.
Reverse Engineering of Sheet Metal Parts Using Machine Vision
Authors: Yan Jiajun , de Sam Lazaro Anthony
Published: June 2008

This study presents a method for measuring the dimensions of 2D-objects using optical methods for edge detection. The approach is based on measuring “a scale image” to obtain an invariant factor which is then used to acquire the required geometry information from the real image. The pre-process of the object measurement can be characterized by a group technique which is called “minimizing required image information method”. In this paper, the method of measurement in two steps, pre-processing and measurement will be presented. The application of this technique for reverse engineering of sheet metal parts will be demonstrated.
Strategy for Effective Visualization of CFD Datasets in Virtual Environments
Authors: Wasfy Tamer , Wasfy Ayman
Published: June 2008

A strategy for effective visualization of CFD datasets in virtual environments (VEs) is presented. The VE is driven by an object-oriented scene-graph-based toolkit. The key elements of the proposed visualization strategy are: (a) strategic use of global and local visualization objects; (b) effective use of multimodal interfaces including hierarchical GUIs and naturallanguage voice commands; (c) a general efficient point search algorithm that allows constructing the visualization objects at interactive frame rates. The global visualization objects include arrays of stream lines/ribbons/volumes, colored/contoured surfaces; volume arrows; iso-surfaces; vortex cores and boundary layer visualization objects (including surfacerestricted streamlines and separation/attachment lines). The local visualization objects include: stream lines/ribbons/volumes probes; colored/contoured surfaces; elevation surfaces; surface arrows; local iso-surfaces, crosssection line probes, and 2D graphs. Primitive response quantities such as pressure, velocity and density as well as derived quantities such as Mach number, pressure gradient, and shock waves can be used in all visualizations.
On the Geometry of Low Degree-of-Freedom Digital Clay Human-Computer Interface Devices
Authors: Rosen David , Nguyen Austina , Wang Hongqing
Published: June 2008

Digital clay represents a new type of 3-D human-computer interface device that enables tactile and haptic interactions. The digital clay surface is computer controlled and can be commanded to acquire a wide variety of desired shapes, or be deformed by the user in a manner similar to that of real clay. In this paper, we present the ideas underlying digital clay and an example design of a digital clay device meant for generalpurpose modeling. We also introduce the concept of low degree-of-freedom digital clay devices, in which the clay surface can acquire a limited range of shapes, for example, to describe the shapes of automotive front-ends. Each degree of freedom moves a region of the clay surface through a range of predefined shapes. We investigate geometric modeling techniques for defining the ranges of shapes and relate the shapes to forward and inverse kinematics of the deformable structures that control surface shape. To illustrate the application of the digital clay concept, an example low degreeof-freedom clay device for modeling automotive front ends is presented and discussed.
A Virtual Reality Based Decision Support Framework for Manufacturing Simulation
Authors: Banerjee Amarnath , Cecil J.
Published: June 2008

In this paper, a virtual reality based decision support framework for manufacturing applications is discussed. The Decision Support Framework includes the use of an Enterprise Modeling Language (EML) and a Decision Support System. EML is used to create an information-oriented model of the processes and activities in a target domain, which provides a structured basis for understanding the activities and relationships in that domain. This understanding facilitates the creation of a virtual environment for manufacturing analysis. The Decision Support System is used to interface operations (process related) information in a real time control system with representations of objects in a virtual reality based environment.
Development of a Web-Based Customer-Oriented Interactive Virtual Environment for Mobile Phone Design
Authors: Wang Peijun , Bja¨rnemo Robert , Motte Damien
Published: June 2008

During recent years, mobile phone companies have experienced market-related difficulties that result in increasing competition globally. In an attempt to maintain or increase their market share, enterprises reorganize their resources and employ new technologies to sharpen their competitive edges. Moreover, with the globalization, more and more companies become multi-sited. Efficient and timely collaboration and communication among the development team members become critical for product success. This paper proposes a web-based interactive virtual environment for mobile phone design, named VMPDS (Virtual Mobile Phone Design Space). The features of the system include the combination of web technology and VR (Virtual Reality) technology, the ability to deal with and extend the product model database, adequate interaction for 3-D product model modification and customization, and usefulness for the examination and evaluation of product concept design. The system is implemented by using standard open technologies such as VRML (Virtual Reality Modeling Language), Java, SAI (Script Authoring Interface) and EAI (External Authoring Interface) to assure accessibility and platformindependence.
Design Under Uncertainty Using Monte Carlo Simulation and Probabilistic Sufficiency Factor
Authors: Qu Xueyong , Haftka Raphael T.
Published: June 2008

Monte Carlo simulation is commonly employed to evaluate system probability of failure for problems with multiple failure modes in design under uncertainty. The probability calculated from Monte Carlo simulation has random errors due to limited sample size, which create numerical noise in the dependence of the probability on design variables. This in turn may lead the design to spurious optimum. A probabilistic sufficiency factor (PSF) approach is proposed that combines safety factor and probability of failure. The PSF represents a factor of safety relative to a target probability of failure, and it can be calculated from the results of Monte Carlo simulation (MCS) with little extra computation. The paper presents the use of PSF with a design response surface (DRS), which fits it as function of design variables, filtering out the noise in the results of MCS. It is shown that the DRS for the PSF is more accurate than DRS for probability of failure or for safety index. The PSF also provides more information than probability of failure or safety index for the optimization procedure in regions of low probability of failure. Therefore, the convergence of reliability-based optimization is accelerated. The PSF gives a measure of safety that can be used more readily than probability of failure or safety index by designers to estimate the required weight increase to reach a target safety level. To reduce the computational cost of reliability-based design optimization, a variable-fidelity technique and deterministic optimization were combined with probabilistic sufficiency factor approach. Example problems were studied here to demonstrate the methodology.
An Approach to Robust Multiattribute Concept Selection
Authors: Gurnani Ashwin P. , See Tung-King , Lewis Kemper
Published: June 2008

In this paper, we investigate and extend a method of selecting among a set of concepts or alternatives using multiple, potentially conflicting criteria. This method, called the Hypothetical Equivalents and Inequivalents Method (HEIM), has been shown to avoid the many pitfalls of already existing methods for such problems, such as pair-wise comparison, ranking methods, rating methods, and weighted sum approaches. The existence of multiple optimal sets of attribute weights based on a set of stated preferences is investigated. Using simple visualization techniques, we show that there is a range of weights that satisfy the constraints of HEIM. Depending on the attribute weights used, multiple possible alternative winners could exist. The visualization techniques, coupled with an indifference point analysis, are then used to understand the robustness of the solution obtained and determine the appropriate additional constraints necessary to identify a single robust optimal alternative.
Application of the Sequential Optimization and Reliability Assessment Method to Structural Design Problems
Authors: Liu Huibin , Chen Wei , Sheng Jie , Gea Hae Chang
Published: June 2008

The use of probabilistic optimization in structural design applications is hindered by the huge computational cost associated with evaluating probabilistic characteristics, where the computationally expensive finite element method (FEM) is often used for simulating design performance. In this paper, a Sequential Optimization and Reliability Assessment (SORA) method with analytical derivatives is applied to improve the efficiency of probabilistic structural optimization. With the SORA method, a single loop strategy that decouples the optimization and the reliability assessment is used to significantly reduce the computational demand of probabilistic optimization. Analytical sensitivities of displacement and stress functionals derived from finite element formulations are incorporated into the probability analysis without recurring excessive cost. The benefits of our proposed methods are demonstrated through two truss design problems by comparing the results with using conventional approaches. Results show that the SORA method with analytical derivatives is the most efficient with satisfactory accuracy.
Robust Optimization of an Automotive Valvetrain Using a Multiobjective Genetic Algorithm
Authors: Kazancioglu Emre , Wu Guangquan , Ko Jeonghan , Bohac Stanislav , Filipi Zoran , Hu S. Jack , Assanis Dennis , Saitou Kazuhiro
Published: June 2008

A robust optimization of an automobile valvetrain is presented where the variation of engine performances due to the component dimensional variations is minimized subject to the constraints on mean engine performances. The dimensional variations of valvetrain components are statistically characterized based on the measurements of the actual components. Monte Carlo simulation is used on a neural network model built from an integrated high fidelity valvetrain-engine model, to obtain the mean and standard deviation of horsepower, torque and fuel consumption. Assuming the component production cost is inversely proportional to the coefficient of variation of its dimensions, a multi-objective optimization problem minimizing the variation in engine performances and the total production cost of components is solved by a multi-objective genetic algorithm (MOGA). The comparisons using the newly developed Pareto front quality index (PFQI) indicate that MOGA generates the Pareto fronts of substantially higher quality, than SQP with varying weights on the objectives. The current design of the valvetrain is compared with two alternative designs on the obtained Pareto front, which suggested potential improvements.