Contact force algorithm in explicit transient analysis using finite-element method

The contact force calculation has significant effect on the accuracy and efficiency of finite-element analysis for contact-impact problems. In this paper, an algorithm for contact force calculation in explicit finite-element analysis is presented. The classical penalty method and Lagrange multiplier method are combined by interpreting the impenetrability between two bodies as a control parameter in this algorithm. The constraints of no-penetration condition and sticking condition are imposed accurately without the requirement to choose a proper parameter as in the penalty method. With this algorithm, no coupled system of equations needs to be solved. The interaction of contact pairs applied on same segment is treated with iteration procedure. This algorithm is totally compatible with the explicit time integration scheme. Numerical examples demonstrate that this algorithm performs well for contact-impact problems. In contrast to the penalty method, this algorithm increases the stable time step because the effect of penalty parameter to the stability does not exist. The new algorithm provides an accurate and efficient way to study contact-impact problems with explicit finite-element method. (c) 2007 Elsevier B.V. All rights reserved.