DSEM时域数值模型求解关键影响因素分析

Analyses of key influencing factors of time-domain numerical methods based on DSEM

人工材料阻尼系数与有限区域尺寸对以阻尼溶剂抽取法(DSEM)为基础的动力结构-地基相互作用分析的效率与精度影响显著.为研究这种影响,以弹性地基上半无限杆的波动理论为基础,在频域中推导了人工高阻尼条件下谐波幅值衰减的解析表达,进而结合对杆端交界面力的时域数值分析,给出了适于工程应用的关键因素参考取值.提出了基于加速度求解的DSEM隐式积分算法,克服了原位移求解模式中存在的结构-地基交界面显隐式积分步长协调性的问题,可方便地与结构侧的动力响应分析相结合.数值算例表明该算法具有良好的稳定性和计算效率,亦验证了关键因素参考取值的有效性.

The key factors in the dynamic soil-structure interaction analyses based on the damping-solvent extraction method（DSEM）,artificial material damping coefficient and domain size have a significant effect on the accuracy and efficiency.In order to investigate the influence of the key factors,an analytical formula of attenuation of oscillation amplitude under artificial high damping is deduced in the frequency domain on the basis of wave propagation theory in the semi-infinite rod on an elastic foundation.What is more,the reference values used in engineering of key factors are suggested through the numerical evaluation of interaction forces of semi-infinite rod in the time domain.An implicit DSEM integral algorithm in which acceleration is solved firstly is proposed to solve the coordination problem of explicit and implicit integral algorithm with different time steps on the interface between structure and soil region and can combine with dynamic response analysis of structures conveniently.The numerical results demonstrate good stability and efficiency of the proposed algorithm.In the meantime,the reference values of the key factors exhibit good effectiveness.