From CAD models to F.E. simulations through a feature-based approach

The preparation of simulation models from CAD models is still a difficult task since shape changes are often required to adapt a component or a mechanical system to the hypotheses and specifications of the simulation model. Detail removal or idealization operations are among the current treatments performed during the preparation of simulation models. In this paper we introduce the concept of simplification features, which allows a user to improve the efficiency of the analysis model generation process. Therefore Form Feature semantics and simulation data are attached to a polyhedral model during the preparation phase, to ease the Finite Element (FE) details identification and removal. The process flow corresponding to the insertion of the FE model preparation phase into the CAD/FEA framework is described in detail to highlight the versatility of the process according to the category of the input model as well as the main steps of the simplification process. This process flow stresses also the influence of the different information sources involved in the preparation task. They consist of the geometric and feature data of the object and the mechanical data of related to the process under examination. The need of a topological model able to represent non-manifold components is discussed as well as the need for the to user to specify the analysis attributes over the boundary of components either isolated or part of an assembly The proposed topological representation of allows the software application to combine several geometric representations such as Form feature and polyhedral representations; therefore it is possible to propagate the B-Rep information from a STEP file, as well as feature information into the polyhedral representation used during the simplification process.