地震动时频能量分布及其对结构最大位移响应的影响规律分析

Time-frequency energy distribution of ground motion and its effect on the maximal displacement of structural response

地震动特性的掌握对了解结构的地震响应及地震损伤至关重要。本论文采用时频分析方法研究地震动时频能量分布及其对结构反应的影响规律。地震动的时频能量分布由匹配追踪分解算法得到,既有效地反映不同频率成分的能量在时间上的分布,也能反映峰值加速度发生时刻附近存在的频率成分。通过分析构造的具有相同峰值加速度、傅立叶幅度谱和持时的人工地震地面运动以及线性结构的地震响应,表明时频能量分布对线弹性结构的影响很大,地震地面运动分解的原子有效幅度越大,循环特征越大,线弹性结构的位移也越大。本论文揭示地震地面运动时频能量分布对结构响应具有重要影响。

In earthquake engineering,the knowledge of the ground motion is essential to an understanding of the seismic response and damage of structures. In this paper,time-frequency method is used to analyze the time-frequency energy distribution of ground motion and its effect on the structural response. The time-frequency energy distribution of ground motion is obtained by matching pursuit decomposition,which shows not only the time evolution of the energy of frequency contents,but also the frequency contents near the time instant of peak ground acceleration. Artificial signals with same peak absolute value,frequency content and duration are generated,and the structural responses under these artificial ground motions are compared. The results show the effect of time-frequency energy distribution on the structural response is significant. The response is bigger with larger effective amplitude and cycling characteristics of the decomposed atom. The time-frequency energy distribution of ground motion has strong influence on the maximal response of the linear structure.