Research On Modeling-Analysis Incorporate Approach And Technology Via Unified Feature Representation

Three-dimensional CAD modeling and structural analysis is an important part of new-product development, since the integration of modeling and analysis is one of the key technologies to achieve efficient product design, and is of great significance for improving the efficiency of product design. Currently, the pre-processes such as transformation, model simplification and meshing, consume considerable time in the CAD/CAE integration. Meanwhile, the reuse of CAE analysis information, e.g., boundary condition (BC), cannot be efficiently solved in the product design process, which greatly affects the efficiency of the product design. In this paper, the integration methods of product modeling and analysis were studied deeply and systematically by studying on a unified representation of product CAD modeling, CAE analysis features and the reconstruction mechanism of building a product feature, and thereby an incorporate software prototype system of modeling-analysis was built initially. The main research work is as follows:(1) Due to the differences between the models of product modeling and analysis, the association and representation of analysis and modeling information were discussed in detail. Furthermore, structural analysis information (e.g., BCs) was treated as a feature. The concepts of integrated feature and mapping methods of BC feature information were proposed. Therefore, the organic integration and sharing of CAD/CAE feature information can be realized, which is beneficial to improve the uniformity of CAE and CAD models of a product and avoid repeated conversion and data redundancy between such models, and builds the technical groundwork for the integration of modeling-analysis.(2) To implement the reuse of analysis feature information in the constructure process of existing product, traditional modeling feature coding methods and techniques were expanded. Moreover, we focused on researching mechanism and algorithms about coding, transmitting and recoding related to feature information of the whole and partial BC features, and the hybrid coding strategies and methods of BC features were proposed. Simultaneously, the coding of analysis and modeling features are treated as properties associated to the product model, and provide the basic algorithm for the reuse of BC feature information in CAE analysis.(3) In order to reconstruct the integrated feature in the history-based modeling-analysis constructing process, the reuse mechanism and management of integrated features were researched. We focused on investigating the dependencies between BC features and modeling features as well as the data consistency of BC feature coding transmitting. Besides, the adaptive reconstruction algorithm of BC feature were proposed based on the dependency graph method of integrated modeling-analysis features. This method can support reconstruction of different boundary conditions which effectively guarantee reusability of analysis and modeling features, and reduce some repeated interaction for designers to improve the efficiency of product design.(4) Since there is the inconsistent mesh between CAD display model and CAE analysis using the finite-element method which is a resource demanding process, boundary integral theory was adopted to analyze product structure performance analysis based on the integrated boundary mesh model. This method can unify the mesh model of CAD and CAE as well as reducing mesh dimensions. Additionally, it is able to save resources and improve accuracy. Meanwhile, combining with the fast multipole method and GPU parallel computing, an accelerated algorithm of quadratic element boundary integral is proposed. This algorithm contributes to improve the efficiency of the analysis, and provides a theoretical basis together with the core algorithm of the rapid analysis calculating for the realization of integrated geometric modeling with structural performance analysis of a product.(5) With regard to the limitations of the current integrated CAD/CAE technology and system architecture, a three-dimensional CAD/CAE integration system framework of product modeling organically integrated with performance analysis was proposed, as well as reconstruction mechanism and strategy of CAD/CAE integrated feature. Thereby unified management for product modeling, feature analysis of data model and feature history are implemented, so that it can effectively reduce data redundancy of CAD/CAE integrated system.(6) Based on the above theoretical research and the independently developed 3D modeling software-InteSolid, a modeling-analysis integrated prototype system is built. The method of feature representation, data structure, core algorithm and feature management mechanism were expanded in this prototype system. This method implements the integration and adaptive reconstruction of modeling-analysis features, which reduces the repeated feature definition to improve the design efficiency. Furthmore, the effectiveness of the proposed algorithm was validated by some engineering cases, which provided a reference and guidance for the research and development of the new-generation three-dimensional CAD/CAE integration software.