A unified contact algorithm based on the territory concept

Abstract A unified contact algorithm based on the territory concept is described. This contact algorithm treats general contact interfaces in explicit finite element analysis. Systematic formulation of the problem is given. Contact segments from all potential contact boundaries are treated as a single set. The concept of hierarchy territory and contact territory are used to facilitate efficient searching procedures. To reduce the frequency of global searching, the hierarchy territory is expanded. A three-dimensional bucket sort algorithm is used to find test pairs efficiently. Pre-contact and post-contact searchign procedures are distinguished. The calculation of contact forces is performed with the defence node algorithm, which is based on the Lagrange multiplier method. Thus, it does not demand any algorithmic parameter, nor affects the numerical stability of the explicit solution procedure. Numerical results show that this contact algorithm is reliable and efficient.