面向杆系结构的离散元异步长计算方法

为了提升离散元法处理连续介质问题的计算效率, 提出一种基于重叠颗粒的离散元分区异步长计算方法来处理连续介质问题。该方法采用颗粒分割将连续介质划分为若干子分区, 各分区采用velocity-Verlet积分格式求解运动方程。相邻分区通过重叠颗粒构成局部耦合区域, 边界数据传递过程中不涉及插值和截断过程。数值算例表明, 该方法在保证高精度的同时有效地降低了计算时间。在实际应用中可以有针对性地将连续介质划分为不同尺度颗粒的分区, 根据问题规模及分区颗粒尺度特性采用不同时间步长, 节省存储空间且大幅提升计算效率。

A Multi-time-step Discrete Element Method for Bar Structures

To improve computational efficiency of discrete element method(DEM), referring to domain decomposition method and sub-cycle method in finite element method, a discrete element partition asynchronous time step computing method based on overlapping particles was proposed to deal with continuous medium problems. In the method, the continuum is divided into sub-domains. The velocity-Verlet integral scheme is used to solve the motion equation in sub-domains. Local action regions are formed with overlapping particles in adjacent sub-domains. Interpolation and truncation are not involved in transfer process of boundary data. Numerical examples show that accuracy of the method is high and the computation time is reduced effectively. In practical application, continuous media could be divided into several sub-domains with different particles size, and different time steps are adopted according to particle size characteristics of the sub-domains, with which storage space could be saved and computing efficiency improved greatly.