碎片云撞击声发射信号能量特征小波包分析

利用小波包分析技术对碎片云撞击载荷作用下铝合金板声发射信号的能量分布特征进行了研究。首先，介绍了碎片云撞击信号的获取方案及撞击引起的损伤情况；其次，对获取的声发射信号进行小波包分析，得到了信号在频率带上能量分布特征图。最后，讨论了碎片云撞击损伤特征与声发射信号能量分布的关系。分析结果发现，对于相同质量的弹丸，随着其破碎程度的提高，形成的碎片云对后板的损伤程度减少；弹丸具有的初始速度越大，弹丸破碎越完全，碎片云撞击声发射信号中的能量越小；当弹丸破碎程度低时，碎片云撞击引起的声发射信号能量集中在约488kHz以下；弹丸破碎程度越高，信号中488kHz以上的能量所占总能量的比例越大。

Wavelet packet analysis for acoustic emission signals caused by debris cloud impact

The feature of energy distribution of acoustic emission signals caused by debris cloud impact of an aluminum alloy plate was investigated based on the wavelet packet method.Firstly,the process to obtain the signals and the damage caused by debris cloud impact were introduced.Secondly,the signals were analyzed by using wavelet packet,and the change of energy distribution in different frequency bands was obtained.Finally,the relationship between debris cloud impact damage characteristics and acoustic emission signals energy distribution was discussed.The results showed that for the same mass of projectiles,the more completely they are broken,the less damage on the plate the debris cloud leads to;with higher initial speed,the projectiles are broken more completely,the signals caused by debris cloud impact have less energy;when the projectiles are not completely broken,the acoustic emission signal energy is concentrated within the range of less than 488kHz;the energy proportion of the signal above 488kHz increases as the projectiles are broken more completely.