基于小波分析的声发射源定位技术

TECHNIQUE OF ACOUSTIC EMISSIONSOURCE LOCATING BASED ONWAVELET ANALYSIS

声发射全波形采集技术为基于波形分析的声源定位方法提供了可能。在板状构件中声波的传播模式较为复杂,且不同模式的波到达时间和波速均不相同,从而带来了声源定位误差。将时频幅度分析方法引入声发射源定位技术:从接收到的信号中提取出某一频率的柔性波随时间变化的规律,在理论分析的基础上证明,这个分离信号的最大幅值点所对应的时间就是该频率柔性波群速度的到达时间。根据这个到达时间,以及实际测量出的群速度就可以实现声发射源更精确的定位,试验结果也证明了这种方法的可靠性。

The technique of acoustic emission (AE) signal full waveform acquisition provides possibility of source location based on waveform analysis. The modal of the AE signal propagation in a plate is complicated. The arrival time and the group velocity are various. These factors lead to the error of AE source location. A new approach based on time-frequency-amplitude (TFA) transform is introduced to locate AE sources. In the received signal, the behaviors of a certain frequency flexural mode wave are found by using wavelet transform. Theoretical analysis shows that the peak of the magnitude of separating signal is related to the arrival time of the flexural mode wave group velocity. Using the arrival time and the group velocity, which measured in the filed, the AE source can be located more precise. Experimental result shows that AE source location based on the TFA method agreed well with the actual location.