The Algorithm Research Of Contact-Impact Problems

Contact-impact widely exists in engineering. The behavior of contact-impact computation presents geometric nonlinearity, material nonlinearity and boundary condition nonlinearity. So the analysis and research of contact-impact phenomena is very important. To solve the contact-impact problems, it is an efficient way to adopt the numerical simulation with the help of finite element method. Doing some helpful contribution to this field is right the aim of the present paper. The main work can be shown as followings:1. Accurate equations are formulated for nonlinear contact-impact finite element analysis. During the process of solving equations, the following issues are discussed: the spacial discrete model of finite element, nonlinear geometrical equations, nonlinear material constitute model, time integration algorithm, etc.2. A new local contact search algorithm is given. In the new algorithm, before calculating the projection, the contact test pairs are lessened again with the technique of vector calculation.3. The Defence Node Algorithm has been developed. Here, we consider the contact point as defence node directly. Compared with the penalty function method, which is the most widely used method, this method can meet the contact constraint conditions completely. At the same time, this method don't introduce a new unknown variable, so the finite element equations are still decoupled, and also can be analyzed using explicit time integration method, which can improve the computational efficiency.