Abstract: Discrete element method (DEM) is more and more widely used to deal with continuum problems. The calculation time is closely related to the particle size, and a single time step will cause a great waste of computing resources. In order to improve the computational efficiency, referring to the domain decomposition method and sub-cycle method in the finite element method, a discrete element partition asynchronous time step computing method based on overlapping particles was proposed to deal with the continuous medium problem. In this method, the continuum was divided into several sub-domains. The sub-domains used the velocity-Verlet integral scheme to solve the motion equation. The local action region was formed by overlapping particles in adjacent sub-domains. Interpolation and truncation were not involved in transfer process of boundary data. Numerical examples showed that the accuracy of the proposed method was high and the computation time was further reduced effectively. In practical application, continuous media could be divided into several sub-domains with different particles size, and different time steps were adopted according to the particles size characteristics of the sub-domains, by which storage space could be saved and computing efficiency greatly improved

Key words: discrete element method, linked bar, overlapping particles, asynchronous step, continuous medium