基于Hilbert-Huang变换的长周期地震动能量时频分布比较研究  

Comparative study on energy time-frequency distribution of long-period ground motions based on Hilbert-Huang Transform

作　　者：王博[1] 白国良[1] 王超群[1] 代慧娟[1] 

机构地区：[1]西安建筑科技大学土木工程学院,陕西西安710055

出　　处：《地震工程与工程振动》2013年第3期71-80,共10页Earthquake Engineering and Engineering Dynamics

基　　金：国家自然科学基金项目(50578129)

摘　　要：远场类谐和地震动与近断层脉冲型地震动是两种不同类型的长周期地震动,确定其能量的时频分布特性对理解长周期地震动作用下长周期结构的反应特点及揭示结构破坏机理具有重要意义。各选10条远场类谐和地震动、近断层脉冲型地震动与普通地震动,利用Hilbert-Huang变换,提取出各地震动的3-D Hilbert幅值谱、边际谱、Hilbert能量谱与瞬时能量曲线,在此基础上提出累积能量谱、强频段、能量时间分布系数等概念,定义了多个指标对比分析三类地震动的长周期特性、宽频带特性和脉冲特性。结果表明:与普通地震动相比,远场类谐和地震动与近断层脉冲型地震动的能量主要集中于较低的频段,长周期特性明显,且远场类谐和地震动的能量集中频段低于近断层脉冲型地震动;远场类谐和地震动的强频段宽度小于其他两类地震动,且能量在强频段内的分布比其他两类地震动均匀;与其他两类地震动相比,远场类谐和地震动的脉冲特性不明显;三类地震动的卓越频率与能量时间分布系数均存在明显的分布规律,可以作为地震动的能量表征参数。The far-field harmonic-like ground motion and the near-fault pulse-like ground motion are two different kinds of long-period ground motions.Characterization of energy time-frequency distribution of long-period ground motions are of great significance in understanding the response characteristics of the long-period structure under long-period ground motions and revealing the structural failure mechanism.Firstly,10 ordinary ground motions,10 far-field harmonic-like ground motions and 10 near-fault pulse-like ground motions are selected,and then this paper extracts 3-D Hilbert amplitude spectrum,marginal spectrum,Hilbert energy spectrum and instantaneous energy curve based on Hilbert-Huang transform.On this basis,the concept of accumulated energy spectrum,strong frequency band,and time distribution coefficient of energy are proposed to explore the energy time-frequency distribution of the ground motions based on some defined indicators.The results show that：（1） Energy of the two kinds of long-period ground motions focuses on the low frequency band,and the centralized frequency band of the far-field harmonic-like ground motion is lower than that of the near-fault pulse-like ground motion.（2） The width of strong frequency band of the far-field harmonic-like ground motion is narrower than the other two kinds of ground motions,and its distribution of the energy in the strong frequency band is more uniform than the other two kinds of ground motions.（3） The pulse characteristic of the far-field harmonic-like ground motion is more unobvious than that of the other two kinds of ground motions.（4） The predominant frequency and the time distribution coefficient of energy can be used as the energy characterization parameters,because these two indicators of all three kinds of ground motions have obvious distribution law.

关 键 词：长周期地震动 能量时频分布 HILBERT-HUANG变换 强频段 能量时间分布系数 

分 类 号：P315.915[天文地球—地震学]