Automated generation of FEA models through idealization operators

Abstract

This paper describes an automated idealization process of FEA models monitored by a mechanical criterion. This process, based on transformations of a polyhedral geometry, allows large geometric modifications including topology modifications (such as hole removal). Polyhedra are used as input geometry for model adaptation purposes because of their significant freedom for shape modifications compared with CSG or B-Rep models. These polyhedra act as intermediate models to form the adapted input geometry required for a finite element mesh generation. These idealizations are carried out through a vertex removal process which transforms the geometry of a part while preserving it within a discrete envelope defined around its initial geometry. This envelope is obtained from a mechanical criterion which can be based either on an a posteriori error estimator or on a priori estimation. The use of such a criterion ensures that all geometric transformations which keep the geometry of the part within this envelope do not significantly change the results of the FEA In addition to geometric transformations strictly respecting this envelope, operators used for idealization are also able to transfer specific data (like boundary conditions) from the initial geometry to the idealized geometry. Such operators allow an extended automation of geometry simplification and idealization processes and ensure that the new geometry is more suited to the element size requirements of the mesh generation process. This approach is illustrated and validated through an example. Copyright © 2000 John Wiley & Sons, Ltd.