离散元法在求解三维冲击动力学问题中的应用

提出了三维连结型离散模型，建立了可实现连结型模型(用于连续介质)-接触型模型(用于非连续介质)转化的三维离散元计算程序，用来模拟连续介质转变为非连续介质的力学过程．利用该计算程序对冲击载荷下混凝土块体内(连续体情况下)的应力波传播过程进行了数值模拟．将计算结果的数值与LS-DYNA程序计算的结果进行比较，验证了该计算程序的计算精度．在此基础上，模拟了混凝土块体的动态破坏(连续介质向非连续介质转化)过程．其计算结果可用动画显示，得到的破坏形式与由实验得到的破坏形式相近．两个算例说明该离散元模型及其计算程序是模拟计算伴随有连续介质向非连续介质转变的动态破坏问题的有力工具．

THE APPLICATION OF DISCRETE ELEMENT METHOD IN SOLVING THREE-DIMENSIONAL IMPACT DYNAMICS PROBLEMS

A three-dimensional discrete element model with connective type is presented. Moreover, a three-dimensional numerical analysis code, which can carry out the transitional process from connective model (for continuum) to contact model (for non-continuum), is developed for simulating the mechanics processes from continuum to non-continuum. The wave propagation process in a concrete block (as continuum) made of cement grout under impact loading is numerically simulated by using this code. Comparing its numerical results with those by LS-DYNA, the calculation accuracy of the model and algorithm are proved. Furthermore, the failure process of the concrete block under quasi-static loading is demonstrated, which illustrates the basic dynamic transitional process from continuum to non-continuum. The results of calculation can be displayed by animation. The damage modes are similar to the experimental results. The two numerical examples above prove that our model and its code are powerful and efficient tools for simulating the dynamic failure problems accompanying with the transition from continuum to non-comtinuum. It also shows that the discrete element method will have widespread availability and perfect development prospect.