Base On Sub-Model Railway Vehicle Structural Intensity Refined Calculation

The sub-modeling method is a high-level analysing technique of the finite element method and has a very broad practical value in FEM analysis. This method is high efficient and high precision in solving the complex problems of stress and strain. But the process of analysis is minute and complicated and easy to make operational mistakes in the practical application. In order to spread this method in the area of the intensity computation for railway vehicles, we finished the fine analysis to key parts of a railway wagon through sub-modeling method according to the analysis of intensity and the structural features of the wagon body, and elaborate on methods and characteristics in application about the sub-modeling technique.The sub-model technology supplied in ANSYS is based on results obtained through analyzing the overall model, intercepting a key-part model through model-cutting method and redividing finer grids in the local region, applying the actual loads and the boundary conditions to this local-region model, and regarding the cutting boundary displacement of the overall model as the forcible displacement load to apply to this local region, and analyzing anew the local-region model to obtain a more precise result.In this article we have carried on the static intensity finite element analysis to a new-type railway wagon body by using HyperMesh, ANSYS and I-DEAS and have succeeded to carry on the finite element fine computation of intensity to this railway truck body with the sub-modeling method. First, establishing the geometric model which is 1/4 of the whole body based on symmetries. Second, establishing the finite element analyzing model through using hypostatic cells in HyperMesh and generating in number 460,088 nodes and 247,339 cells including 241,754 cells shaped in hexahedron, 5,584 cells shaped in pentahedron and 1 rigid cell and two different methods of modeling are brought forward. There are two models including the full-connection model(i.e. model 1) and the simulating-welding-line-connection model(i.e. model 2) and three types of loading including longitudinal loading(tensile loading and compressive loading), vertical loading and torsional loading. Then finishing the FEM analysis of static intensity for the overall model of the wagon body in ANSYS and getting the reasonable FEM model under different loading phases according to the contrast between calculating results and testing results. And composing the stress in accordance with the principles of utmost syntheses to validate that the wagon body meets the requirements of intensity in the case of resultant stress. Finally, using sub-modeling method to carry on the fine analyses to reasonable FEM models under different loading phases and having obtained calculating results in the submodel much closer to testing results than in the overall model. So we can better actualize the fine calculation to key parts of the wagon body and lay the foundation for the fine calculation to a variety of railway wagons and carriages based on the sub-modeling method.