摘要
以原始地震波为母波,以与抗震规范相容的功率谱为目标谱,利用功率谱与小波包变换系数之间的关系式,提出了利用小波包变换合成人工地震波的新方法.通过实例分析发现:人工合成的地震波功率谱与目标谱符合较好,而且继承了母波的非平稳特性;具有相似功率谱的地震波的时程图却有很大的差异,在实际工程中选择地震波时,不但要考虑地震波的频域特性,还要考虑其时频特性;人工合成地震波时,应选择多个小波基函数进行精度对比,从中挑选出误差小精度高的小波基函数作为实际合成地震波使用;不同分解水平下的合成精度也有所差异,并不是分解水平越高人工合成地震波的精度也越高.
A wavelet packet-based procedure is presented to generate an accelerogram whose power spectrum is compatible with a target spectrum by using actual earthquake records as parents. The numerical results show that the power spectrums of reconstructed accelerograms have good matching with the target spectrum and the reconstructed accelerograms preserve the non-stationary features of the parents accelerograms. The reconstructed accelerograms whose parents are different have similar power spectrum, but their time-histories are very different. So when the accelerograms are chosen in actual project, not only the frequency characteristic but also the time-frequency characteristic of accel erograms should be considered. The precision of artificial earthquake is affected by the wavelet func tions. So several wavelet functions should be chosen to compare their precision and one wavelet func tion which has least error and more precision is picked to generate an artificial earthquake. In addition, this study shows that the decomposed level of earthquake records also affects the precision of ar tificial earthquake.
出处
《华中科技大学学报（自然科学版）》
EI
CAS
CSCD
北大核心
2008年第3期42-45,共4页
Journal of Huazhong University of Science and Technology(Natural Science Edition)
基金
国家自然科学基金资助项目(50778079)
湖北省自然科学基金资助项目(2006ABA067)
关键词
人工地震波
小波包变换
功率谱
时频特性
非平稳特性
artificial earthquakes ground motion
wavelet packet transform
power spectrum
time frequency characteristic
non-stationary characteristic
