Fea of Frictional Contact Problems Using Nagata Patches for Surfaces Description

The numerical simulation of problems involving contact with friction between deformable and rigid bodies is highly dependent of the predicted contact conditions, which are continuously changing during the process. In the case of sheet metal forming processes, the forming tools are assumed to behave rigidly, and thus only the definition of the outer surfaces is required for the simulation. This paper presents the contact search algorithms currently implemented in DD3IMP in-house finite element solver, which has been continuously developed and optimized to simulate sheet metal forming processes. Nowadays, in DD3IMP it is possible to describe the forming tools either using Bézier or Nagata patches, for which distinct contact search algorithms are adopted. The results show that the accuracy and computation cost of both algorithms is similar. The Nagata patch description is more versatile than Bézier since it can be extracted using any combination of CAD and mesh generation software. Besides, the numerical results accuracy is almost independent of the polyhedral mesh generated.