Abstract
In this paper, a dynamic model coupled with linear and nonlinear stiffness is proposed for nonlinear cushioning packaging system based on critical component. The approximate analytical solution for the nonlinear free vibration of the coupled system is derived by applying He's variational iteration method. And the maximum dropping shock response of the critical component is obtained, based on which, the dropping damage evaluation parameters for cushioning packaging system are predicted, agreeing well with the reported experiment results. The results may lead to thorough understanding of the dropping damage mechanism of packaged products based on critical components.