The Finite Element Analysis On Strength, Stiffness And Fatigue Character Of Automobile Body's Die

The automobile is one of the significant products in China industrial development. China encourages the development of and research on the molding and die technology of auto bodies and parts, which effectively accelerates the advancing paces of our automotive industry. At present, however, our auto body dies mostly depend on import. The forming technics and die technology are the main difficulties in the development of our automotive industry. Only with the advanced auto body forming thecnics and die technology will we develop a sustainable, innovative and independent automotive industry.In the recent twenty years, with the development of CAD/CAE/CAM, the design of auto body die technology and punch technics has broke through the traditional means, and the computer simulation has been an active domain of the die design and analysis. By this means, we can predict the stress and strain, temperature distribution, fatigue damnification, and possible disfigurement and invalidation form in the design and analysis of dies. These are good for optimizing technics parameters and die structures, and are of great importance to assure quality, cut down waste, shorten period, decrease cost for the die design and development.Subject to the above, the research stated in this paper mainly focuses on the following:Based on one practical project supplied by the Chang Chun King Mesh Company Ltd., the finite element model of one die was built on computer with the software named HYPERMESH as the preprocessing tool. With ANSYS as the solver and post-processing software, through the comparative study of the two finite element models, the concave die was analyzed on the strength, stiffness and fatigue character with the finite element analysis software, thus, the die strength convergence domain was found and the biggest strength, stiffness, and displacement were predicted. The fatigue life of die was predicted according the results of the static analysis. The detailed work was as following:In the first chapter, the development and the means of the finite element simulation analysis of dies were generally stated after the writer had read a lot of literatures and got to know the present states of die research and die finite element analysis in the domestic and outside worlds. Also, the development and classification of engineering analysis were stated, and the mechanics knowledge was reviewed in this chapter.In the second chapter, the concept of and the main ideas about FEM were introduced. The detailed experience of applying finite element analysis software in structure analysis was stated, including the simplification of geometrical models, the build of finite element models, and the unit transition and the evaluation methods of unit quality, etc.In the third chapter, the software HYPERMESH and ANSYS were studied and applied in the research; two finite element models, which have different units, of one geometrical model were built with the preprocessing software HYPERMESH; the two finite element models were solved by the software ANSYS and two results were got; the two results were compared.In the fourth chapter, the analysis methods of fatigue and the fatigue theory were introduced. The fatigue life of die was predicted according to the fatigue module of software ANSYS based on the static analysis results stated in Chapter Three.In the fifth chapter, the results and advantages of the research were stated, and the shortages of the research were referred to. At the same time some aspects needed improving were also mentioned.The significances of the research are:Firstly, the writer has got to known the common process of finite element analysis of dies or other parts with the finite element software, and has learned some knowledge and skills of software application, which laid a good foundation for further study.Secondly, the research has realized the finite element analysis of strength, stiffness and fatigue character of the little deformability die with the software HYPERMESH and ANSYS, which offered a new way to analyze the little deformability die.Thirdly, the writer has further studied and applied the finite element analysis knowledge and the fatigue theory, which improved the writer's quality of theories.Finally,the innovative points of the research are:1) The research was carried out in a comparative way. Comparison is used in the processes of preprocessing, solution, post-processing and fatigue analysis.2) The finite element of cubic body was creatively used in building the finite element model. The model was piled up with the finite elements of cubic bodies, which improved the simulation of the model.In the writer's opinion, simulation analysis was widely used, which is greatly beneficial to the development of modern industry. Chinese automobile die industry will be stronger and stronger with the progress in the simulation analysis research. Although the simulation analysis industry began a bit later in China than in other developed countries, the market of application is large. At the same time, the finite element method will become an effective tool in simulation analysis with our Chinese own efforts to develop and research on it. Chinese automobile die industry will progress more and more quickly with the advancement of simulation analysis, and China will become a big country in the domain of automobile die design and research.