Automated 3D Surface Contact for Nastran FEA

Download it now!

Login first to download.

NEiNastran V9 adds a powerful new feature that allows automatic surface contact generation (ASCG) between discontinuous bodies. This feature is ideally suited for models in which the contact areas are initially touching and where little sliding is expected.

The automated surface contact generation works in three phases. First the user defines parameters such as which elements should be considered for each contact pair generated (the default is all solid and shell elements in the model), what the near tolerance is for objects to be considered in contact with each other, and the type of contact to be generated (i.e., general, welded, bi-directional sliding, or rough). Using these user defined parameters, a region of elements is considered. The default would be all solid and shell elements in the model. The first phase consists of identifying the external surfaces of these elements. For shells it would be the entire element. For solids it would be any exterior surface. The second phase then looks for grid points that are positioned on or near and above (within the user defined tolerance) of each surface. The third phase eliminates invalid contact scenarios by considering surface normals. It is important that surfaces that are to be welded are not offset and that shell normals are oriented properly.