EU-China collaboration in design: research in Web-enabled collaborative design supported by the Asia-Link and Asia IT&C projects

The research of Web-enabled collaboration in total design supported by the European Union's Asia Link project [1] and Asia IT&C project is reported in this paper. The two projects both aim at enhancing research collaboration between the EU and China. The Virtual Research Institute (VRI) is described first, which is the platform for the collaboration for the Asia Link project and is established by utilizing the advanced Web techniques; and then, the framework for the collaboration and the Web techniques involved in the research are presented which represent the major research of the Asia IT&C project. The effective collaboration between the project partners and the impacts of the project outcome on the partnership are also discussed

Stereometric Design for Desk-Top SFF Fabrication

Solid Freeform Fabrication (SFF) technologies refer to the fabrication of physical parts directly from computer based solid models described by STL (Stereo Lithography) or VRML (Virtual Reality Modeling Language) files generated by Computer-Aided Design (CAD) systems. Most of the SFF processes produce parts by building them layer by layer using a row by row pattern, though it is possible to build the part using other patterns. The SFF technology represents a challenge to designers who, in addition to making decisions concerning optimum shape and functionality of the entire part, have'to take under consideration several other manufacturing factors. These factors cover a wide range of technical issues such as Computer-Aided Design model generation, part description and model slicing files, laser path files, precision of part design, rendering patterns, manufacturing tolerances, thermal expansion and residual stress phenomena. This paper investigates the effect of rendering patterns on the integrity, material characteristics and mechanical properties of the parts prepared by a desk-top SFF device using diode lasers. Fe - Bronze (Cu - Sn) premixed metal powders were used as the starting material. The particle size was about 100 /lm to 200 /lm. Density, tensile strength and microstructure of the parts prepared using different rendering patterns were characterized. The results were analyzed to seek optimal rendering patterns. It was noticed that the samples were strong along the laser scanning direction, while they were weak perpendicular to the scanning direction. These results suggest that the laser scanning patterns should be designed to minimize the warping and maximize the strength of the part in the direction depending on the part's function.Mechanical Engineerin

Testing in the incremental design and development of complex products

Testing is an important aspect of design and development which consumes significant time and resource in many companies. However, it has received less research attention than many other activities in product development, and especially, very few publications report empirical studies of engineering testing. Such studies are needed to establish the importance of testing and inform the development of pragmatic support methods. This paper combines insights from literature study with findings from three empirical studies of testing. The case studies concern incrementally developed complex products in the automotive domain. A description of testing practice as observed in these studies is provided, confirming that testing activities are used for multiple purposes depending on the context, and are intertwined with design from start to finish of the development process, not done after it as many models depict. Descriptive process models are developed to indicate some of the key insights, and opportunities for further research are suggested

DC-CAD : a new software solution for product design

Thesis (S.B.)--Massachusetts Institute of Technology, Dept. of Mechanical Engineering, 2007.Vita.Includes bibliographical references.Many computer aided design (CAD) software packages focus on detailed design and not on early stage, conceptual design. The ability to conceptualize and sketch early versions of a product solution is currently limited to paper and pencil or to inadequate computer-aided industrial design programs (CAID) that focus mainly on surface design, not product design. Working on a design as a group also poses problems since the team can be geographically distributed. In an attempt to address the current inadequacies of CAD systems for distributed conceptual design, my thesis proposes a vision for a new CAD program, DC-CAD. This vision anticipates network-orientated conceptual design, and encompasses capabilities for multiple users to collaborate simultaneously on design, compare & evaluate concept sketches, comment on designs and merge changes from other designers, transfer data to detailed design CAD programs, and record concept changes over time. MIT's Product Engineering Class (2.009) was used as the basis for conceiving the software system. By analyzing design challenges that arose during the course, new software features are suggested to mitigate such problems.(cont.) The end result is a clear vision for a new program, DC-CAD, and a storyboard example of how it could be used in a futuristic 2.009 setting. The thesis closes with recommendations on how to pursue the implementation and realization of such a CAD system.by Mark D. Egan.S.B

Parametric CAD modeling: An analysis of strategies for design reusability

CAD model quality in parametric design scenarios largely determines the level of flexibility and adaptability of a 3D model (how easy it is to alter the geometry) as well as its reusability (the ability to use existing geometry in other contexts and applications). In the context of mechanical CAD systems, the nature of the feature-based parametric modeling paradigm, which is based on parent-child interdependencies between features, allows a wide selection of approaches for creating a specific model. Despite the virtually unlimited range of possible strategies for modeling a part, only a small number of them can guarantee an appropriate internal structure which results in a truly reusable CAD model. In this paper, we present an analysis of formal CAD modeling strategies and best practices for history-based parametric design: Delphi's horizontal modeling, explicit reference modeling, and resilient modeling. Aspects considered in our study include the rationale to avoid the creation of unnecessary feature interdependencies, the sequence and selection criteria for those features, and the effects of parent/child relations on model alteration. We provide a comparative evaluation of these strategies in the form of a series of experiments using three industrial CAD models with different levels of complexity. We analyze the internal structure of the models and compare their robustness and flexibility when the geometry is modified. The results reveal significant advantages of formal modeling methodologies, particularly resilient techniques, over non-structured approaches as well as the unexpected problems of the horizontal strategy in numerous modeling situations. (C)2016 Elsevier Ltd. All rights reserved.Camba, JD.; Contero, M.; Company, P. (2016). Parametric CAD modeling: An analysis of strategies for design reusability. Computer-Aided Design. 74:18-31. doi:10.1016/j.cad.2016.01.003S18317

Template-based geometric transformations of a functionally enriched DMU into FE assembly models

International audiencePre-processing of CAD models derived from Digital Mock-Ups (DMUs) into finite element (FE) models is usually completed after many tedious tasks of model preparation and shape transformations. It is highly valuable for simulation engineers to automate time-consuming sequences of assembly preparation processes. Here, it is proposed to use an enriched DMU with geometric interfaces between components (contacts and interferences) and functional properties. Then, the key concept of template-based transformation can connect to assembly functions to locate consistent sets of components in the DMU. Subsequently, sets of shape transformations feed the template content to adapt components to FE requirements. To precisely monitor the friction areas and the mesh around bolts, the template creates sub-domains into their tightened components and preserves the consistency of geometric interfaces for the mesh generation purposes. From a user-selected assembly function, the method is able to robustly identify, locate and transform groups of components while preserving the consistency of the assembly needed for FE models. To enlarge the scope of the template in the assembly function taxonomy, it is shown how the concept of dependent function enforces the geometric and functional consistency of the transformed assembly. To demonstrate the proposed approach, a business oriented prototype processes bolted junctions of aeronautical structures