Strategy for Effective Visualization of CFD Datasets in Virtual Environments

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.

A Framework for Efficient and More Realistic Haptics Applications

This paper describes the development of a generic framework for implementing realistic cross-platform haptic virtual reality applications. Currently, freely available Software Development Kits (SDKs) deal with a single Haptic Interaction Point (HIP), i.e. the tip of the haptic probe. However, many applications as path planning, virtual assembly, medical or dental simulations, as well as scientific exploration require object-object interactions, meaning any part of the complex 3D object attached to the probe collides with the other objects in the virtual scene. Collision detections and penetration depths between 3D objects must be quickly computed to generate forces to be displayed by the haptic device. In these circumstances, implementation of haptic applications is very challenging when the numbers, stiffness and/or complexity of objects in the scene are considerable, mainly because of high update rates needed to avoid instabilities of the system. The proposed framework meets this high requirement and provides a high-performance test bed for further research in algorithms for collision detection and generation of haptic forces.

Shell or Plate Idealization on a Polyhedral Model for Finite Element Analyses

Very often, geometric transformations are required to adapt the geometry of a component to the requirements and hypotheses of a structural model in order to generate a Finite Element (FE) mesh suitable for modeling some physical phenomenon. This co-called idealization process is usually time consuming. This paper introduces a new set of operators to perform this preparation phase. The operators proposed are based on a polyhedral representation of the component to enable structural analyses to be integrated at various stages of the design process without requiring a model issued from a CAD system. The operators fit into an approach where geometrical criteria and mechanical ones are distinguished. Here, a first set of geometric operators is described and mechanical criteria are highlighted to set their relative positions. Two distinct stages are set up in applying geometric operators: firstly, candidate areas reflecting plate or shell morphology are identified and transformed into open surfaces ; secondly, the connections between the shell or plate elements are addressed through mechanical and geometrical criteria to allow the analyst to express the hypotheses he (resp. she) requires. Across these stages, the continuity and integrity of the model is always preserved, which enables a wide variety of treatment of the connections between the plate or shell elements, as it is often required when modeling structures. Finally, examples are provided to illustrate the efficiency and the potential of the approach proposed.

XML-Based Integration of Design, Analysis and Manufacturing

The integration of design, analysis and manufacturing is a challenging issue in product development. Much research focuses on creating data exchange standards such as STL, IGES, EDI, and STEP etc. However, these standards are not ideal in data exchange and communication via the Web. In this paper, a unified framework based on XML was created to integrate design, analysis, and manufacturing. The structures of DTDs and XML files of geometric design, finite element analysis and NC machining were developed. Key technologies of supporting the XML-based integration and information communication, such as DOM, SAX and SOAP etc. were discussed. XML-based integration will shorten the development cycle, save costs in product development, and finally improve the competitive capability in the global competition of product development.

Data Model Support to Assist the Concurrent Design of Injection Plastic Parts and Their Moulds

Product models come from the analysis of data requirements to support product design and manufacture. These models are implemented in databases aimed at providing information to software applications that assist the concurrent design of products. This paper presents the specifications of data models to assist the concurrent design of injection plastic parts and their moulds. The product models are original since they capture part and mould life cycle aspects using the same data structure. The models also link product functional information to the design process and consider the capacities of an injection machine. The paper introduces the underlined structure of the above mentioned data models and uses a case study to show their capabilities. Finally, some conclusions are presented.

ERMM: An Engineering Requirements Management Method

Automotive product development is a lengthy and complex process. There exists a large body of various requirements, standards, and regulations, which need to be followed by all engineering activities throughout the entire vehicle development process. The underlying relationships between these requirements are very complicated. Although most of engineering requirements can be found in various engineering databases, it is the lack of the underlying relationship between the requirements and their association with the design that makes it extremely difficult for even experienced engineers to follow the requirements in their dayto-day work. This paper introduces an Engineering Requirements Management Method (ERMM) that captures these interrelationships and associations using a matrix-based representation. A case study with a real automotive component is also presented.

A Model Repository for Automotive Embedded Control Systems Design

Model-based product development methodologies are becoming more widely used by developers of automotive embedded control systems. This paper presents a model repository intended to provide configuration management, reuse, and sharing infrastructure in support of this trend. An initial set of repository requirements is presented and then augmented with lessons-learned from a pilot realization of the system. This pilot realization is discussed with respect to implementation and application. A repository data model is also described.

Transient Analysis of Heated Vapor Extraction System for Effective Remediation

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.

Simulation of New Automobile Lighting Systems for a Nightdrive Application

For the development of new automobile lighting systems, special raytracing methods are needed to create physically correct simulations of the illumination properties. For further evaluation, test drives with physical prototypes are still necessary. But changing weather and lighting conditions make the test drive results not fully comparable. Therefore, a high number of test drives have to be performed. This leads to a costintensive and time-consuming development process. Virtual test drives at night combined with a realistic simulation of a lighting system’s illumination characteristics can minimize the number of real nightdrives and allow reproducible testing conditions as well as comparable results. A close-to-reality simulation poses high demands on real-time methods for calculating and displaying illumination data in a virtual scene. Furthermore, the geometry model of the scenery which is to be illuminated needs to be adapted to fulfill these demands. This paper introduces a real-time illumination method for use in a nightdrive simulation which illuminates scenery models using coarse polygon meshes.

Feature-Based Part Similarity Assessment Method Using Convex Decomposition

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.