The non-stationary characteristics of an earthquake ground motion are dependent on the phase difference spectrum, which is proportional to the phase derivatives. As viewed from the energy of acceleration time history, the time of PGA is related to the mean value of the phase derivatives while the duration of strong ground motion is related to the variance of the phase derivatives. The intensity moment formula of uniformly modulated random process is modified in this paper in order that the modified formula is applicable to the general non-stationary process. In the process of simulating the non-stationary earthquake ground motion field correlated to a specified earthquake record, the probability density function of phase derivatives for the specified earthquake record is calculated; then both the phase derivatives and the random phase spectrums of the synthesized ground motions are generated. The simulated ground motions, expressed as a function of the power spectrum, coherence function and random phase angles, are generated by discrete Fourier transform.
Na Yang;Yu;ji TIAN and Qing;shan YANG.
Artificial Ground Motions Correlated to a Specified Earthquake Record[J]. Journal of Vibration and Shock, 2012, 31(19): 36-39
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