基于Hilbert-Huang变换的结构位移瞬时能量谱研究

运用HHT(Hilbert-Huang变换)对地震波作用下的结构位移响应进行分析,证实结构位移响应的瞬时能量谱峰值和地震波的瞬时能量谱峰值在长周期结构中并不是完全同步的,其出现的时间主要取决于结构的自振周期,但也与地震动的类型有关.仿真计算的结果表明,结构的自振周期较长时,结构位移响应的瞬时能量谱峰值会发生明显的滞后.从而能够清楚地解释在唐山地震中,长周期结构的破坏与倒塌并不发生在地震动强度最大的时刻,而多数是在地震动末期,甚至在地震动完全消失之后.

Instantaneous energy spectrum of structure displacement based on Hilbert- Huang transform

This paper proposes a HHT-bases approach to analyze structure's displacement response,the results show that for long self-oscillation structure,the peak values for instantaneous energy spectrum and that of earthquake wave do not occur at the same time,self-oscillation frequency and earthquake style play crucial roles in determining its instantaneous energy peak value appearance time.The simulation results also indicate that for a certain structure,if the self-oscillation period takes longer time,instantaneous energy spectrum under the displacement response have a distinct delay,this can clearly explain that in the Tangshan catastrophe,the demolition and collapse for long time-period structure does not happen at the greatest density of earthquake ground motion,but most times at the final stage of earthquake ground motion,or even after the earthquake ground motion completely ends.