基于morlet小波与模态分析的突发型声发射源定位研究

Study on the Location of Sudden Acoustic Emission Sources Based on Morlet Wavelet and Modal Analysis

在建立基于声发射技术的裂纹产生与拓展检测系统的基础上。以薄钢板为实验对象,研究了Lamb波在薄板中传播的频散及多模态特性,并结合morlet小波时频联合分析方法,提出了一种针对声发射信号在薄板中传播时产生的不同模态进行识别的方法。通过提取不同模态波到达同一传感器的时间差并依据不同模态波对应的波速实现对出现裂纹的位置进行定位。经过实验研究表明,运用该方法不仅能准确地识别A0、S0模态波并实现对声发射源进行精确定位。

On the basis of establishing a system for detecting the generation and expansion of cracks based on the acoustic emission technique,this paper took a steel plate as the experimental object to study the dispersion and multimode characteristics of Lamb wave propagating in a thin plate and proposed a method that recognizes the different modes generated when the acoustic emission signal propagates in the thin plate combining with morlet wavelet timefrequency joint. The position of the crack is located by extracting the time of different modes wave to the same sensor and according to the wave velocity corresponding to different modes wave. The experimental results show that the method can identify accurately A0,S0 mode wave,but also realize the accurately locating of acoustic emission source.