基于加速度输入的结构-地基相互作用分析分区递归时域算法

An acceleration input stagger method in time domain for dynamic soil-structure interaction analysis

由于无限地基动刚度的频率相关性,用于结构-地基动力相互作用分析的各种方法基本上都是将地震动作用转化为作用在边界上的力,需要同时包括地震动位移、速度和加速度输入信息.为简化,基于阻尼抽取法,提出一种基于加速度输入的分区递归数值求解算法,该算法仅需要地震动加速度信息,与地震动加速度成比例的结构惯性力作为地震荷载输入,可方便地确定由于结构震动对地基变位的影响,同时避免了无限地基动刚度时域算法中的褶积分.数值算例表明该方法具有良好的精度与应用的简便性.

The seismic actions are usually applied to structure by transforming the seismic displacement, velocity and acceleration to external loads acting on the boundary in almost all the methods for the dynamic structure-foundation interaction analysis because of frequency-dependant feature of infinite soil impedance. Based on the damping-solvent extraction method, a sub-regional stagger procedure is proposed to deal with the analysis of dynamic soil-structure interaction in time domain, in which only the seismic acceleration is needed and the seismic action is transformed to mass-proportional loads. The scattering effects induced by structure vibration on the foundation can be easily obtained and the frequency dependence or convolution integral, as required in other algorithms in time domain, is avoided. The numerical implementation of the method is given in detail and the test examples are presented. The results demonstrate good accuracy and feasibility of the proposed method.