Adaptation of cad model topology for finite element analysis
Résumé
The preparation of a Finite Element Analysis (FEA) model from a computer aided design (CAD) model is still a difficult task since its boundary representation (B-Rep) is often composed of a large number of faces with some of them possibly narrow or having short edges that are smaller than the desired FE size (for mesh generation). Consequently, these faces and edges considered as mesh generation constraints generate artifacts that are irrelevant for the meshing process. Such inconsistencies often cause either poorly-shaped elements or meshes that are locally over-densified. These inconsistencies not only slow down the solver (using too many elements) but also produce poor or inappropriate simulation results. In this context, we propose a "Mesh Constraint Topology" (MCT) model with automatic adaptation operators aiming at transforming a CAD model boundary decomposition into a FE model one which only contains mesh-relevant faces, edges and vertices, i.e. an explicit data model this is intrinsic to the meshing process. We provide a set of criteria that can be used to transform the paving of CAD model booundary using MCT transformations, i.e. edge deletion, vertex deletion, edge collapsing, vertices merging. The proposed simplification criteria take into account of the size map, the discretization errors, and the boundary conditions. Application and results are presented through the adaptation of CAD models using the proposed simplification criteria.