To Modulate Earthquake Wave By Wavelet Analysis Method

There are three element in earthquake wave.seismic intensity,seismic frequency and the time of earthquake wave continuance.To modulate seismic wave namely to modulate the three element in earthquake wave.The methods include the adjustment of the ratio of law.This way can only satisfy the maximum acceleration of quake,site characterization cycle,the predominant period of quake,as well as holding at the time of request,can not meet the earthquake response spectrum and power spectrum.This paper adopts the wavelet series to represent the acceleration time-history, and analyze the instantaneous frequency of it.Then adjust the amplitude to fit the response spectrum of the results to the designing response spectrum.Because of the true quake,the duration of the results do not changed.So this way conforms the conditions of time-history analysis method.This article has been based on the results of the research base is mainly done in the following areas:Based on the last research achievements,this paper improved them by:(1) Collecting the methods using on the simulation of quake.(2) Iintroducing the wavelet analysis method and Fourier transform,and proving the efficient of using wavelet on the quake analysis.(3) Simulating Qian'an ground motion record by 2-B spline wavelet,and representing it by wavelet series.Then adjusting the composition of the frequency, dividing it to some adjacent frequency zones by Mllat algorithm which based on the MRA,and test the results by FFT.(4) Assuming the predominant period Tg and natural period T adopting the quake record to adjust the amplitude of some frequency zones.;the range of the adjustment is[0.1,T_g]and[T₁-ΔT₁,T₁+ΔT₂];after the adjustment,the results can fit the response spectrum of the true records.