The arithmetics of contact element, including three aspects of interface condition, Coulomb friction type and the weak formulation of interface condition are investigated in detail.

• 在接触单元的力学机理方面,从接触界面条件、Coulomb摩擦类型和接触界面条件的弱形式等三个方面对接触单元的算法进行了详细的研究。