Accuracy and Computational Complexity Analysis of Design Models Created by Virtual Sculpting

We have developed an experimental virtual sculpting system with haptic interface, which allows the user to create a freeform model interactively. The virtual sculpting method is based on the metaphor of carving a solid block into a 3D freeform object. The PHANToM™ manipulator is used to provide the position and orientation data of the sculpting tool and to generate haptic sensation to the user’s hand during the sculpting process. The goal is to provide a high-fidelity simulation system with real-time performance and adequate accuracy of the generated model. In order to understand the limitations on the geometric details that can be generated, we perform an accuracy analysis in different aspects. The computational complexity due to various parameters of the virtual sculpting system is also analyzed. Numerical data are presented to verify the analytical results.

Federated Product Models for Enabling Simulation-Based Product Lifecycle Management

Across product lifecycle processes, engineers continually analyze product behavior and refine product specifications. Owing to the collaborative and multi-disciplinary nature of product realization, engineers work on subsets of a product’s specification, also known as a product view, and use their expertise to analyze domain-specific (e.g., electrical, structural, thermal) product behavior. In this paper, we present the notion of a product view federation that embodies engineering processes related to the creation, enrichment and reuse of a particular product view. We make the first step towards answering the following question — Can one formalize the process of creating a product view federation from component federates to enable knowledge reuse? We describe and exemplify one particular graph-based inference approach for creating the product view federation.

Advances of the Finite Element Modeling Markup Language

Development of the finite element modeling Markup Language (femML) was motivated by the need to address data exchange issues associated with intra- and inter-application interoperability in the context of finite element modeling and analysis. This paper describes femML advances during the past four years and describes current status of various tools and technologies associated with femML. In particular, the current schema is described along with XSLT-based translation of femML to SVG and X3D for quick model visualization. Java, C++ and Visual Basic tools have been developed for model editing and visualization as well. The paper concludes with identification of standing issues to be resolved relative to femML’s evolution and the future directions and plans about further evolution of femML.

A Toolbox for Tripod Design, Simulation, and Monitoring

The paper presents a concept and implementation of a toolbox for the design and application of the tripod-based parallel kinematic machines (PKMs). The toolbox is a suite of design tools to support the users from the conceptual design to the actual application of the tripod-based PKMs. These design tools have been individually developed in different languages and they are integrated seamlessly using a Java-based platform. Users can access all of the design tools through a user-friendly graphical interface. It is the first computer-aided design system specially developed for tripod-based PKMs. The toolbox includes some implementations of our innovative methodologies, such as a forward kinematics solver, the concept of joint workspace analysis, on-line monitoring based on forward kinematics, and the concept of motion purity analysis. The paper gives an overview on the toolbox architecture, GUI, and some key technologies.

Ontologies and Fine-Grained Control Over Sharing of Engineering Modeling Knowledge in a Web Based Engineering Environment

Within the knowledge modeling community the use of ontologies in the construction of knowledge intensive systems is now widespread. Ontologies are used to facilitate knowledge sharing, reuse, agent interoperability and knowledge acquisition. We have developed an ontology for representing and sharing engineering analysis modeling (EAM) knowledge in a web-based environment and implemented these ontologies into a computational knowledge base system, called ON-TEAM, using Prote´ge´1. In this paper we present new object-oriented methods that operate on the EAM knowledge base to perform specific tasks. One such method is the creation of a flat technical report that describes the properties or class relationships of an engineering modeling analysis class and/or the modeling knowledge involved in the development of a specific engineering analysis model. This method is a JAVA application that accesses the EAM knowledge base application using the Prote´ge´ application programming interface. It presents the user a graphical user interface for selecting the EAM class or specific analysis model instance and then exports the appropriate knowledge to a text file to form the basis of a technical report. Secondly, a method controlling knowledge access and sharing is under development which allocates permissions to portions of the knowledge base according to accessibility permissions. This method controls as efficiently as possible fine grain knowledge sharing. Both the methods acting together enable automatic generation of recipient-specific technical reports based on the recipient’s security permissions, customized knowledge viewing, and customized knowledge exporting through various knowledge exchange formats such as XML Walsh [1], RDF Klyne [2], etc. Finally, implementation of these methods and our EAM knowledge base application as components within commercial web-based distributed software architecture is presented.

Applications of PhotoModeler in Accident Reconstruction

Photographic methods of analyzing vehicles and scenes for the purpose of accident reconstruction have been well researched and documented. Photogrammetric analysis has appeared in various forms and levels of complexity over the years. Mathematical relationships have been researched and presented depicting the methods and bases of these techniques. This paper will present some new tools and methodologies in the process of photographic analysis. The PhotoModeler program will be utilized to demonstrate applications of digital photogrammetry in the field of accident reconstruction. Several different methodologies, including single and multiple photograph projects using calibrated and inverse cameras, will be evaluated and demonstrated. Additionally, comparisons to traditional methods of measurements will be presented. It will be demonstrated that the use of digital photogrammetry has advanced the science of accident reconstruction by employing computer and digital technology to achieve greater efficiency and improved accuracy.

Adaptive Mesh Generation for Finite Element Analysis of Functionally Graded Materials

Finite Element Analysis (FEA) is an important step for the design of structures or components formed by heterogeneous objects such as multi-material objects, Functionally Graded Materials (FGMs), etc. The main objective of the FEA-based design of heterogeneous objects is to simultaneously optimize both geometric shapes and material distributions over the design domain (e.g., Homogenization Design Method). However, the accuracy of the FEA-based design wholly depends on the quality of the finite element models generated. Therefore, there exists an increasing need for developing a new mesh generation algorithm adaptive to both geometric complexity and material distributions. In this paper, a two-dimensional adaptive mesh generation algorithm is proposed based on the discretization by which continuous material variation inside an object is converted into step-wise variation. The proposed algorithm first creates nodes on the iso-material contours of the discretized solid models. Triangular meshes are then generated inside each iso-material region formed by iso-material contours. Current implementation considers two-dimensional problems and thus needs to be extended to include three-dimensional problems in the near future.

Applying Information Economics and Imprecise Probabilities to Data Collection in Design

One important aspect of the engineering design process is the sequence of design decisions, each consisting of a formulation phase and a solution phase. As part of the decision formulation, engineers must decide what information to use to support the decision. Since information comes at a cost, a cost-benefit trade-off must be made. Previous work has considered these trade-offs in cases in which all relevant probability distributions were precisely known. However, engineers frequently must estimate these distributions by gathering sample data during the information collection phase of the decision process. In this paper, we introduce principles of information economics to guide decisions on information collection. We present a method that enables designers to bound the value of information in the case of unknown distributions by using imprecise probabilities to characterize the current state of information. We illustrate this method with an example material strength characterization for a pressure vessel design problem, in which we explore the basic performance, subtleties, and limitations of the method.

Manufacturing Execution Systems Interoperability and Web Services Technologies

Manufacturing Execution Systems (MES) rely between the shop floor and many systems that support the operation of a manufacturing enterprise such as Production and Inventory and Enterprise Resource Planning Tools. Interoperability with a multitude of platforms is thus one of the main problems to solve for implementation of a MES. This paper describes a software architecture based on the use of Web services technologies and discusses how interoperability issues are resolved in a much more seamless manner than with other previous middleware technologies.

Facilitating Meta-Design via Separation of Problem, Product, and Process Information

Different products necessitate different design processes. Determining which such process is most appropriate for a particular product, in turn, requires its delineation before the design of the product under consideration. The phase where design processes are composed is called meta-design. Despite its importance, current simulation-based design frameworks such as FIPER, ModelCenter, and iSIGHT do not support meta-design. This oversight can be attributed at least in part to the fact that these frameworks capture information about products, design processes, and the associated tools in a lumped fashion. Processes are captured in terms of the specific tools employed and the product information, associated with their use, thereby restricting the re-utilization (i.e., reuse via adaptation or customization) of instantiated processes for designing different products. This inherent inability to separate product and process information hinders the exploration of different design process options for designing a product at a fundamental level, thereby restricting meta-design. In order to address this challenge, we propose an approach for distinctly capturing and processing three key components of design related information - a) design problem, b) design process, and c)product. We term this approach, rooted in decision-based design, modularity, and separation of declarative and procedural information, 3-P. The modular separation of information associated with problem, product, and process enables designers to utilize existing knowledge, captured in the form of pre-defined process configurations, for more effectively designing a given product. The proposed approach facilitates the efficient exploration and reconfiguration of design processes, furnishing a much needed and essential basis for meta-design.