Study And Development For Pre And Post Processing Of Ship CAE

CAE software has become an indispensable computational tool in many engineering fields. CAE technology plays an important role in the development of modern industrial technology and high-tech innovation. Good support of pre and post processing is the premise and foundation of CAE technology heading to engineering application.To develop the pre and post processing software system for ship CAE with independent intellectual property rights, the system design and implementation of the software are systematically studied in the thesis. The key algorithm of the main functions, as well as the application in ship field, is further discussed. The detail is as follows:(1)The concept and background of CAE pre-post processing is introduced first to explain the research background, objectives and research content of this thesis.(2)As for the CAE pre-processing, the design and implementation of pre-process of CAE software are first introduced. According to the demand of software engineering, the software requirements, design and implementation are introduced to explain how the entire pre-process of CAE software are fulfiled. The main modules include the geometric modeling, mesh, material definition, property definition, LBC (loads and boundary conditions) definition and so on. By comparison to the MSC.Patran, Femap, in terms of functionality, the software has already met requirements of the pre-process of CAE analysis in ship FEA area, and in some ways is better than them.Then the two key and difficult points in pre process part are introduced, i.e. CAD/CAE model data transforming and automatic mesh generation.Concerning CAD/CAE model data transforming, a set of self-defined model data structure using discrete boundary representation is designed, based which the model data is transformed from CAD to CAE by different interfaces. By the unified data interface, model data is read and transformed from a variety of mainstream and standard CAD model files such as IGES, STEP and so on. By Studing and parsing the STL file and Tribon XML file format, the STL model file and ship CAD model data conversion is realized. Topology reconstruction is used to solve the topology information loss problem in the CAD/CAE model data conversion process.Concerning mesh generation, according to the model data structure, the Advancing Front Technique (AFT) is improved to generate finite element mesh from complex discrete surface like ship model automaticly, which is validated by some typical examples given at last, and the CAD/CAE model data transforming function is also test implicitly.(3)As for the CAE post-processing, likewise, the overall realization ideas of the CAE post-processing software is discussed first. In consideration of the large variety of CAE software, a standard file format of post-processing application data is defined, especially for ship field. The model and result data are converted from all kinds of CAE result files to it to realize basic post functions.Then the implementation of the key features in the CAE post-processing software are described, using a series of custom algorithms or improving existing algorithms to achieve fast display of large-scale model, contour display, arbitrary cross section and its contour display. One of the innovations of this thesis is the rapid display of large-scale model, which realizes quick display of degree freedom model of the 10 million level nodes on the ordinary PC machine, far more pre-post processing software in the world like Patran, Femap, etc.(4)As for the application, based on the research results above, a number of CAE software products are developed through the module selection and improvement, including the pre-process of Jifex for Dalian University of Technology, ship cabin noise prediction software and three-dimensional hydroelastic integrated software.Finally, the main contributions in this work are summarized and further research considerations are proposed.