A parallel two-sided contact algorithm in ALE3D

A scalable parallel algorithm for treating two-sided contact in a finite-element multi-physics code (ALE3D) is presented. This method assumes that proximity between the two sides changes continuously, and uses a local search to update proximity relations each cycle. The evolving communication pattern is treated entirely by local, nearest-neighbor communication; there is no global communication. Opening and closing voids, overlapping and intersecting contact surfaces, and a number of other special features are supported.