Abstract：Discontinuous deformation is a fundamental character of multi-body system. For the general plane problem，divisional parameter principle of minimum potential energy is employed to establish the computational model for discontinuous deformation analysis of multi-body system in this paper. Mathematical formulations of global controlling equations of elastic and elastoplastic analysis of discontinuous deformation of multi-body system are presented and the numerical solution approach is developed. The mothod can not only perform both static and dynamic coupling analysis，but also conduct step-by-step simulation and prediction of deformations and stresses of multi-body system together with complex nonlinear process such as contact stress and relative movement along contact interfaces. The theoretical basis is established for numerical model of discontinuous deformation computational mechanics.
