USING CAD MODELS IN FINITE ELEMENT ANALYSIS

This paper addresses the analysis of some phenomena that occur in finite element structural analysis of the structural models, generated within CAD / CAE / CAM systems, with reference to the microstructures. CAD model is designed based on 2D or 3D geometry of the structure, in order to be used further in the execution stage (CAD - CAM model), which contains standardized tolerances. From a technical point of view, the problem of generating the structures geometry and preparing the geometric model, in order to be introduced in finite element structural analysis is very important today because the majority of structures are represented in CAD systems electronically. Coupling the components in assemblies is necessary for the structural model and contacts modeling between components has to approximate the reality as well as possible. Many times geometric representations in CAD present gaps and interferences due to tolerances and other design factors. Within this problem, the main subjects are related to the treatment applied to this so called gaps arid interference which occur in geometric patterns (partially physical) generated in CAD programs for converting in authentic structural model. Their treatment is largely similar both for macrostructures and microstructures, but, in the case of the last ones, some gaps type "defects" can be capitalized for "defects" simulation in microstructures. Even interferences can be repaired in a way in which specific aspects of the microstructures are capitalized. The repairing and capitalization modes of the gaps and interferences from geometric models or physical geometric CAD models are the main subject of this paper. Applications will focus on repairing CAD models for FEA simulation of the ideal microstructures functioning, as well as, for gaps or interferences of the microstructures with defects, especially their effect and the propagation of these effects.