【摘要】 地震动的非平稳特性主要是由其相位差谱决定的,相位差谱与相位导数之间存在线性倍数关系。根据相位导数的计算公式,从能量的角度解释了相位导数的均值决定了时程峰值的大致发生时刻,相位导数的方差决定了强震段的持续时间。改进了均匀调制非平稳过程的相位导数概率密度函数计算公式中强度谱矩的计算方法,使之能够适用于一般非平稳时程。在模拟与指定地震记录相关的非平稳地震动场方法中,计算指定地震记录相位导数的概率密度函数,并按照该函数生成各点的相位导数,得到各点的随机相位谱;然后采用基于功率谱表示的地震动场合成方法,利用快速傅里叶变换技术生成地震动时程。更多还原

【Abstract】 The non-stationary characteristics of an earthquake ground motion are dependent on its phase difference spectrum being proportional to phase derivatives.From the view point of energy of an acceleration time history,the time of PGA is related to the mean value of phase derivatives while the duration of strong ground motion is related to the variance of phase derivatives.The intensity spectral moment formula of a uniformly modulated non-stationaly random process was modified here in order that the modified formula was applicable to the general non-stationary process.In the process of simulating a non-stationary earthquake ground motion field correlated to a specified earthquake record,the probability density function of the phase derivatives for the specified earthquake record was calculated;then both the phase derivatives and the random phase spectra of the synthesized ground motion points were generated.The time histories of the simulated ground motion field based on a power spectrum expression were generated with fast Fourier transformation.更多还原