Research on Simulation Model of Nonstationary Stochastic Processes in Natural Disasters

• Published in: Applied Mechanics and Materials Vol. 204-208; pp. 3415 - 3422
• Main Authors: Xu, Qing Yang, Hu, Can Yang, Chen, Qing Jun
• Format: Journal Article
• Language: English
• Published: Zurich Trans Tech Publications Ltd 01.10.2012
• Subjects: Orthogonal Hilbert-Huang Transform; Random Phase; Nonstationary Random Processes; Simulation; Hilbert Spectrum
• ISBN: 3037854847; 9783037854846
• ISSN: 1660-9336; 1662-7482; 1662-7482
• DOI: 10.4028/www.scientific.net/AMM.204-208.3415

Simulation of nonstationary processes has become an indispensable tool in study and prevention of natural disasters. A new method of simulation of nonstationary random processes is presented based on the orthogonal HHT spectra of sample observations and random phase. It takes advantage of orthogonal EMD, the instantaneous frequency, amplitude of the Hilbert transform and independent random phase angle, thus overcoming difficulties in the estimation of the frequency modulation and interdependence of frequency and amplitude modulation functions faced by most currently available methods. The new method extracts and preserves the true physical features of the process. The examples of earthquake ground motion and subway vibration, as low frequency and high frequency nonstationary process respectively, were simulated in the paper. The time history of sample, Fourier amplitude spectrum of sample, arithmetic average of sample, variance of sample, Wavelet time-frequency distribution of sample amd autocorrelation coefficient of sample compare well with those of the records. Scattering extent of the peaks of the sample processes is also analyzed in the paper. We can conclude that the method has great potential for engineering applications when dealing with nonstationary, nonlinear random peocesses exist in natural disasters, such as earthquake wave, vibration wave , wind wave and ocean wave.