基于HHT法的地震地面运动局部谱密度估计

ESTIMATION OF LOCAL SPECTRAL DENSITY OF EARTHQUAKE GROUND MOTION BASED ON HHT THEORY

采用能反映时频非平稳特性的时变谱密度(局部谱密度)来描述地震地面运动是非常必要的。本文给出了利用HHT估计地震地面运动局部谱密度的方法。从理论上比较了HHT、STFT和多重过滤法等局部谱密度的估计方法,然后通过具体算例,对理论分析进行了验证。指出利用HHT法来估计局部谱密度在精度和速度方面都有很好的优势,可以作为一种有效的局部谱密度估计方法,这有利于局部谱密度在地震动模型化和结构随机响应分析等方面的应用。

It is necessary to describe earthquake ground motion with local spectral density which is time-dependent and can reflect the non-stationary characteristics. The method using HHT to estimate local spectral density is proposed. Comparisons of estimating precision and speed are firstly carried out theoretically among HHT, STFT and Multifilter. Some numerical examples are evaluated to validate the theoretical results. It is concluded that HHT has great advantages for local spectral density estimation due to its higher precision and faster speed than those of the other two methods so that it is an effective method to evaluate local spectral density. Based on HHT, it is convenient and efficient to apply local spectral density to many aspects of earthquake engineering, such as earthquake ground motion modeling, structural random response analysis.