Contact-impact modeling in explicit transient dynamics

In this article we discuss the treatment of contact-impact modeling in a large deformation explicit transient dynamic setting. Such problems are posed mathematically by demanding the usual satisfaction momentum balance equations and boundary conditions for each body separately, while imposing an additional set of constraints that govern the interaction of these bodies with each other. In applying such methods to contact problems we emphasize two requirements: first, that the treatment of contact should follow from the development of the local (weak) and global (strong) forms of the contact equations in the continuum setting. Algorithms developed from this framework are seen to readily handle the three-dimensional multi-body friction case. Second, and equally important especially in large applications is the practical aspect of computing the closest point projection for contact nodes, an essential component of defining the contact constraints. This calculation is global in nature, accounting for the fact that contact-impact involves multiple bodies interacting in unforeseeable ways. These requirements have guided the development of algorithms capable of treating contact-impact in PRONTO3D (M.W. Heinstein, S.W. Attaway, J.W. Swegle, F.J. Mello, A general purpose contact detection algorithm for nonlinear structural analysis sodes, SAND92-2141, Sandia National Laboratories, Albuquerque, N-87185, 1992) are discussed in this paper.