INTEGRATION OF DESIGN BY SOLID MODELLING AND ANALYSIS BY THE FINITE ELEMENT METHOD.

This paper studies the necessary steps in the integration of Computer Aided Design (CAD) and Finite Element Method structural analysis (FEM). The differences of the respective CAD and FEM data-structures are studied. The CAD data structure is limited to the one of a B-Rep type solid modeler. The contribution of the solid modeler as a tool for the FEM mesh generation is shown and a detailed example illustrates our point. Next, the reverse process, from the analysis results back to the CAD program, is studied. The B-Rep data structure allows for a simple solution: copying the necessary linked list and updating the corresponding point coordinates by the displacements obtained in the FEM analysis. In case of isoparameteric elements and points different from nodes, the inverse isoparametric interpolation must be computed. An example is given of complete two-ways integration. The benefits of such an integration are mainly in shortening the design-analysis iteration times by several orders of magnitude.