论文部分内容阅读
提出一种基于连续小波变换和极点对称模态分解的针对分析非线性非平稳类型的近断层多脉冲地震动信号的联合方法,并介绍了该方法的基本原理和分析优势。利用Matlab平台编制了联合分析程序并针对台站实际地震记录进行了实例分析,得到本征模态函数及瞬时频率,并与经验模态分解方法和小波分解方法分解结果对比。结果表明:(1)该方法不需要人工设定优筛分次数以及分析频率范围;(2)通过方差比率分布曲线能够自适应地确定最优筛分次数,并给出全局最优均值曲线;(3)通过直接积分法能够确定本征模态函数的瞬时频率,直接积分法和Hilbert方法的分析结果基本吻合,但直接积分方法在分析效率方面更突出;(4)实例地震动信号在得到的脉冲能量最强方向上的速度时程幅值较原记录的两个水平向速度幅值增大了50%;(5)该方法针对实例地震动在能量最强方向上抽取的脉冲分量峰值与原信号相差仅0.56%。
A joint method based on continuous wavelet transform and pole-symmetric modal decomposition is proposed for analyzing near-fault multi-pulse ground motions with nonlinear non-stationary type. The basic principle and advantages of this method are also introduced. The Matlab program was used to develop a joint analysis program. The actual earthquake records of the station were analyzed by examples. The intrinsic mode functions and instantaneous frequencies were obtained. The results were compared with the results of empirical mode decomposition and wavelet decomposition. The results show that: (1) The method does not need to manually set the optimal screening times and analyze the frequency range; (2) Through the variance ratio distribution curve, the optimal screening times can be determined adaptively and the global optimal mean curve is given; (3) The instantaneous frequency of the eigenmodel function can be determined by the direct integration method. The direct integration method and the Hilbert method basically agree with each other, but the direct integration method is more prominent in the analysis of efficiency. (4) (5) In this method, the peak value of the pulse component extracted in the strongest energy direction of the case ground motion is peaked Difference from the original signal is only 0.56%.