Numerical simulation of CAD thin structures using the eXtended Finite Element Method and Level Sets

An efficient approach is proposed in order to predict the mechanical response of complex industrial parts. As these structures are usually composed of massive and thin parts, different models have to be mixed together (plate, shells, solid). The transition between these different kinematic assumptions can be problematic and non-linear models cannot be employed depending on the plate model that is considered. Moreover, Finite Element analysis in the case of large and complex assemblies implies tedious meshing steps. The idealization and simplification of these structures into a mix of 2D and 3D Finite Elements usually takes therefore significantly more time than the analysis itself. The objective of the present contribution is to explore a calculation process that enables a simple automation of the meshing steps. Even though potentially computationally more expensive, the meshing automation may lead to drastic time reduction for the CAD to mesh process and a much tighter link between CAD and calculated assembly. Finally, easier and faster design explorations would be allowed. This strategy relies on the use of a non-conforming quadratic approximation that is defined on a sufficiently fine mesh. The eXtended Finite Element Method is used in order to alleviate meshing issues. The mesh and Level-Set function are built from the CAD input, by means of an automated approach. The strategy is verified against analytical solutions and real aerospace substructures.