基于相位差谱的多点激励人工波数值生成算法研究

Research on numerical generation algorithms of multi-support excitation artificial seismic waves based on phase difference spectrum

在三角级数时域合成与快速离散傅里叶变换频域调整算法的基础上,实现基于对数正态分布相位差谱的单点激励人工波的数值生成,着重分析了目标反应谱的迭代拟合技术.结合相关建筑标准中所列地震波,给出了四类场地土的相位差谱统计特征,以利于工程采用.并以描述频谱幅值衰减关系的相干函数与以相位表征的行波效应为条件,实现多点激励地震波的数值生成.同时考虑幅值与相位两因素,保证了多点激励地震波在相邻两近点处的地震位移曲线的一致性合理条件.

According to the phase difference spectrum under log-normal distribution, artificial seismic wave for single-support excitation is firstly numerically generated by utilizing the synthesis technique of time-domain trigonometric series and frequency-domain DFFT, for which the iterative procedure is discussed in detail to make the fitting response spectrum consistent with the aim response spectrum. To meet the needs in engineering practice, statistical characteristics of phase difference spectrum are presented for four various ground conditions by analyzing the seismic waves listed in the related construction criterion for earthquake engineering. Furthermore, under the conditions of both coherence function in amplitude spectrum and traveling wave effect in phase spectrum, an advanced numerical generation method for the artificial seismic waves for multi-support excitation is proposed by expanding the single-point excitation wave. Surely, it can be numerically ensured for the displacement convergence among those near sites along the seismic propagating way by considering both the two effects of amplitude and phase.