Automatic FEM Mesh Generation of 3D Mid-Surface and Solid CAD Model with Shape Recognition Technique 2016-01-1382

This paper describes how we recognize various specific features from the shape of input 3D CAD models and create adequate mesh automatically to meet the detailed mesh rules. It is important to create adequate mesh according to the mesh rules in order to assure the quality of simulation results since simulation results may vary depending on the input FEM mesh. Not only simple features such as fillets, flanges, cylinders, chamfers, and emboss but also other features and complex features such as thin planes, tapered tubes, ribs, and grooves can matter. However, it is time consuming to create adequate FEM mesh according to the mesh rules where the ideal mesh should be different for each analysis phenomena, such as crash, structural, and NVH phenomena. Recognizing shapes of 3D CAD models and controlling mesh for specific features automatically help to reduce time spent on manual mesh modifying work dramatically. To recognize specific features for the mesh rules, we used characteristics of each face of the input 3D CAD models. Characteristics we check are such as the maximum and minimum curvature, the length of perimeters, and inner angle of the face. Which characteristics we check varies on the features. In addition to simple features, we also developed feature recognition algorithm to recognize composite surface features such as a bolt seating surface. We recognize them by combination of faces and their cross sectional shape as well as characteristics of each face. Using the shape recognition technique described in this paper, we achieved to automate mesh generation procedures following the specific mesh rules.