The evaluation of the mechanical behaviour of a product through a Finite Element simulation requires an adaptation of the shape represented in its CAD model. During this shape modification process, several shape sub-domains are removed to simplify the subsequent mesh generation and FE solving tasks. In the proposed approach, the preparation of the simulation model takes place in a software environment based on a mixed geometric representation, which considers as reference polyhedral models but enables to keep the semantics of the input CAD models. We developed efficient complex operators for handling shape sub-domains by combining basic operators acting on the polyhedral model with different kinds of mechanical criteria and semantic information. These operators enable to respect user’s purposes and hypotheses as well as the specifications of the targeted mechanical problem. The removal of a shape sub-domain is always driven by a specific mechanical criterion. Since a priori criteria, acting before the Finite Element analysis, are not able to quantify objectively the influence of shape simplifications, an a posteriori mechanical criterion has been integrated in the process. It evaluates the influence of shape simplifications on the FE analysis results. If a shape detail suppressed during the simplification process proves to be influent on the mechanical behaviour, it can be reinserted on the simplified model, so readapting the initial simulation model.

The a posteriori mechanical criterion, which characterises the influence of object shape variations on their associated mechanical behaviour, is able to quantify how much different object shapes exhibit an equivalent mechanical behaviour when subjected to the same Boundary Conditions. Therefore, several scenarios of product development process have been analysed where this evaluation can be performed automatically.

1. FERRANDES R., MARIN P. LEON J-C., GIANNINI F. “Preparation of Finite Element Models: The Use of an a Posteriori Mechanical Criterion”, Proceedings of “Eurographics Italian Chapter”, February 22-24th, 2006, Catania, Italy
2. FERRANDES R., LEON J-C., MARIN P., GIANNINI F. “A posteriori evaluation of geometric transformations using a mechanical criterion: application to simulation models”, Proceedings of GTMG, February 2006, Cachan, France
3. FERRANDES R., MARIN P., LEON J-C., GIANNINI F. “Evaluation of simplification details for an adaptive shape modelling of components”, Proceedings of “Fifth International Conference on Engineering Computational Technology”, ISBN 1-905088-11-6 N°2, September 2006, Las Palmas de Gran Canaria, Spain
4. FERRANDES R., LEON J-C., MARIN P., GIANNINI F. “An analysis of product development process configurations where an a posteriori FE criterion improves simulation models consistency”, Proceedings of ASME IDETC, Sept. 10-24th, 2006,  Philadelphia, USA
5. FERRANDES R., LEON J-C., MARIN P., GIANNINI F. “Evaluation a posteriori de détails de simplification dans le cadre de la préparation de modelés pour l’analyse éléments finis”, Proceedings of 10éme Colloque Nationale AIP-PRIMECA, April 18-20 th, 2007, La Plagne, France
6. FERRANDES R., MARIN P., LEON J-C., GIANNINI F. “Vérification de la cohérence d’une solution mécanique associée à diverses représentations d’un produit”, Proceedings of 18th Congres Français de Mécanique, August 27-31, 2007, Grenoble, France
7. FERRANDES R., LEON J-C., MARIN P., GIANNINI F., FALCIDIENO B. “Semantic operators for Handling shape sub-domains in FE model preparation”, Proceedings of ASME IDETC, Sept. 04-07th, 2007, Las Vegas, USA