Simulation of non-stationary artificial seismic ground motions based on HHT theory

The artificial seismic ground motions have been synthesized by the use of trigonometric series and time varying power spectrum,which is estimated by the Hilbert-Huang Transform(HHT) theory.The method proposed is different from the traditional procedure,which synthesizes non-stationary artificial seismic ground motion by strength modulation function.It can reflect the energy contribution characteristics on the time-frequency plane and the artificial seismic ground motion is non-stationary both in time and frequency domains.At the same time,the HHT is compared with short-time Fourier transform(STFT) and multi-filter,the comparison results demonstrate that the HHT has higher time-frequency resolution capability and greater advantage in speed and accuracy for estimating the time varying power spectrum.It's more suitable to simulate artificial seismic ground motion.