与荷载同步变化的时间步自动调整方法

A time step's automatic adjustment method with load synchronous variation

为了提高计算效率,针对结构动力时程分析中由时间步长引起的误差,建立了时间步长与相对误差之间的关系式,实现了满足目标误差限的时间步自动调整,丰富了时间自适应理论。通过与解析解的对比,验证了该方法在提高计算效率方面的有效性。在局部,荷载变化越快,对应的自适应时间步长越小;荷载变化越慢,对应的自适应时间步长越大。该方法可以有效解决在冲击荷载、振动荷载、爆炸荷载或地震荷载的动力数值计算中,因时间步长的设置不当导致计算结果发散甚至计算中断的问题。

To improve the numerical calculation efficiency,aiming at errors caused by time step in structural dynamic time history analysis,a relationship between time step and relative error was proposed to realize the time step automatic adjustment,satisfy target error limits,and enrich the time adaptive theory. The effectiveness of this method was validated through comparing the calculating result with the analytical solution to an example. It was shown that in local area,the faster the change of external load,the smaller the corresponding adaptive time step; the method can effectively solve problems of calculation being divergent or interrupted due to improper setting of time step in numerical dynamic computations under impact load,vibration load,explosion load or seismic load.