利用HHT方法进行结构损伤检测研究

高频小波细节信号或内在模函数在时域的奇异性有可能是由于结构损伤引起的,也可能是由于外界环境如载荷突变引起的.针对该问题,利用Hilbert-Huang变换(HHT)方法,通过一个4层框架结构数值算例的计算,利用IMF瞬时频率的变化来区分2类不同的信号奇异性,从而判定结构是否发生了损伤.计算结果表明:损伤时间常数可以准确地由IMF中的信号突变时刻检测出,而且损伤位置可以利用信号奇异性的分布情况确定.

Structural damage detection using Hilbert-Huang transform method

For structural damage detection problem,the spike in the wavelet details or in the "IMFs" can be produced by a sudden change of the structural stiffness or the sudden change of the external load.An application of Hilbert-Huang Transform(HHT) for damage detection is cavried out in order to distinguish two kinds of spikes in the "IMFs".Whether the structure is damaged could be determined by the instantaneous frequency change before and after the spike time instant in the "IMFs".A 4-storey shear-beam building mode simulation results demonstrate the effectiveness of the proposed method.The results show that damage time instant could be accurately detected in terms of damage spikes extracted directly from the measurement data by "EMD" and the damage location could be determined by the spatial distribution of the spikes along the building.