The establishment of finite element model of tractor gearbox shell casting is the basis of finite element analysis and calculation. The same geometric model adopts different grid types and sizes. Even if the same calculation method is adopted, the results will be very different. Moreover, unreasonable grid division will also occupy a lot of computer resources and require a lot of calculation time, and even may not be able to calculate the results. To sum up, the selection of appropriate size and element type is of great significance for accurate modeling.
The establishment of finite element model of tractor gearbox shell casting is completed in HyperMesh. The main points for attention in meshing are as follows:
(1). When dividing the mesh, we should comprehensively consider the characteristics of the geometric model and the requirements of analysis and calculation, select the appropriate element type and size, and the mesh size should be uniform to avoid the mesh with large size difference.
(2). At the same time of meshing, always check and control the mesh quality parameters to increase the quality accuracy after meshing. Unit quality control requirements: for triangular units, the aspect ratio must be less than 5, the Jacobian should be between 1 and 0.7, the internal angle should be between 20 ︒ and 120 ︒ and the warpage angle should not be greater than 10 ︒. For quadrilateral elements, the internal angle of the element should be between 45 ︒ and 120 ︒.
To sum up, select the second-order tetrahedral element with the element size of 5mm, check the divided grid and adjust the unreasonable element, and use rbe2 element to simulate the bolt connection, bearing part and external load bearing point. The model has 1458169 nodes, 890644 units and 33 rbe2 units, as shown in the figure.