利用小波包分析技术对随机激励下法兰螺栓联接结构2次声发射信号进行研究,提取声发射信号随螺栓松动变化的特征量。首先,对螺栓联接结构声发射信号进行小波包分析,得到了声发射信号在不同频带上的能量分布图。然后,总结了随机激励螺栓联接结构声发射信号频带能量的分布规律。分析结果发现螺栓松动变化影响声发射信号频带能量的分布规律,预紧力越大,各频带能量越小;优势频带的能量特性随着预紧力的变化越明显。 Wavelet packet analysis technique was used to study the secondary acoustic emission signals of the flange bolt connection structure under random excitation. The characteristic quantities of the acoustic emission signals with the loosening of the bolts were extracted. First of all, wavelet analysis of acoustic emission signals of bolted joints was carried out, and the energy distribution of acoustic emission signals in different frequency bands was obtained. Then, the energy distribution rules of acoustic emission signal in random-excitation bolted joints are summarized. The results show that the variation of bolt looseness affects the energy distribution of the acoustic emission signal. The larger the pretightening force is, the smaller the energy of each frequency band is. The energy characteristics of the dominant frequency band change more obviously with the pretightening force.