基于规范反应谱的全非平稳地震动过程模拟

摘要

在经典的两类演变功率谱模型基础上,建议了另两类全非平稳地震动过程的演变功率谱模型.为生成与规范反应谱一致的全菲平稳地震动时程,将地震动加速度过程分解为两个独立的随机过程,其一为已知演变功率谱的全非平稳地震动过程,其二为修正的非平稳地震动过程.对于第一个随机过程,应用非平稳过程模拟的谱表示-随机函数方法,即可生成代表性时程集合及其平均反应谱.对于第二个随机过程,其演变功率谱是由调制函数和功率谱密度函数组成,而功率谱密度函数则由第一个随机过程的平均反应谱与规范反应谱的拟合误差计算得到.通过对第二个随机过程演变功率谱的修正,可使合成后的全非平稳地震动过程的平均反应谱与规范反应谱拟合一致.最后,算例验证了此方法的有效性和实用性.%Based on the two classical kinds of evolutionary power spectrum models,two other evolutionary power spectrum models of fully non-stationary ground motion processes are proposed.In order to generate a fully non-stationary ground motion time history consistent with the design response spectrum,the ground motion acceleration process is decomposed into two independent stochastic processes.One is the fully non-stationary ground motion process with known evolutionary power spectrum and the other is the modified non-stationary ground motion process.For the first stochastic process,the representative set of time-histories and its average response spectrum can be generated by applying the spectral representation-random function method of non-stationary process simulation.For the second stochastic process,the evolutionary power spectrum is composed of the modulation function and the power spectral density function of stationary process.And the power spectral density function is obtained from the fitting error of the average response spectrum of the first stochastic process to the design response spectrum.Therefore,through the modification of the evolutionary power spectrum of the second process,the average response spectrum of the composed fully non-stationary ground motion can be fitted to the design response spectrum.Finally,the numerical examples are given to demonstrate the effectiveness and practicability of the proposed method.