In problems involving contact between two boundaries, one of the boundaries is conventionally established as the target surface, and the other as the contact surface. For rigid-flexible contact, the target surface is always the rigid surface, and the contact surface is the deformable surface. For flexible-to-flexible contact, both contact and target surfaces are associated with the deformable bodies. These two surfaces together make up the contact pair.

Use TARGE169 with CONTA172 or CONTA175 to define a 2D contact pair. For 3D contact pairs, use TARGE170 with CONTA174, CONTA175, or CONTA177. Each contact pair is identified via the same real constant number.