基于声发射信号分析的螺栓松动识别

Identification of loose bolted joints based on acoustic emission signal analysis

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 is used to study the secondary acoustic emission signal of bolted joints under random excitation, and the characteristic quantity of the acoustic emission signal which varies with the bolt loosing is extracted. At first, the acoustic emission signal of the bolt joint is decomposed by the wavelet packet analysis, and energy distributions at various frequency bands of the acoustic emission signal are obtained. And then, the energy distribution laws at frequency bands of the acoustic emission signal of the bolted joint under random excitation are obtained. Analysis results show that the looseness degree of the bolted joint affects the energy distribution laws at frequency bands of the acoustic emission signal. The greater the preloading is, the slighter the energy at each frequency band is. In addition, the variation of energy at preponderant frequency band is more obvious with the preloading.