A contact searching algorithm is reviewed and improved for general 3-D contact-impact problems. In the searching scheme, a contact system is decomposed into contact hierarchies, namely the contact body, the contact surface, the contact segment and the contact node. Contact is searched by two distinct searching processes, the pre-contact searching and the post-contact searching. The pre-contact searching is based on the definition of a territory for the contact hierarchy. The post-contact searching is based on the contact history. Automatic generation of the contact hierarchies is considered. The proposed searching algorithm is implemented in the finite element program DYNA3D and numerical tests are performed. Some representative examples are presented. Results and observations from the use of the algorithms are discussed. © 1990.
