Abstract: The analysis of frame structure under impact often brings great difficulties to numerical simulation due to the contradiction between large volume and small impact surface． The failure of frame structure is often caused by the break down of a key component，while the whole structure is still in an elastic state． So it's unnecessary to a-dopt a unified non-linear model in the simulation． In order to deal with this problem，the Numerical Substructure Method (NSM) was adopted to isolate and precisely simulate the components which are in non-linear state． Thus the impact problem of large volume frame structure was transformed into the problem of linear elastic analysis of the main structure and nonlinear analysis of the substructure． Based on NSM，a joint calculation method of OpenSees and LS-DYNA was put forward and implemented． And the method was used to study and analyze the role of ECC material in impact simulation，and to verify the feasibility of the joint calculation method and the superiority of ECC material．

Key words: nonlinear analysis, numerical substructure method, ECC material, fiber model