基于小波尺度谱的转子系统碰摩声发射特性

针对转子系统动静件间发生碰摩时会引起弹性应变而产生声发射,进而可利用声发射来辨识和诊断碰摩故障的特点,首先对碰摩声发射和碰摩振动信号进行了试验对照研究,讨论基于声发射的碰摩辨识别方法的独特优越性.然后,着重对碰摩声发射的特性进行了试验研究,并借助于小波尺度谱优越的时频分析性能,利用小波尺度谱对碰摩声发射的时频特性、传播特性和频散特性等进行了详细分析.分析结果显示小波尺度谱非常适合碰摩声发射这种频率丰富、非平稳和非线性的多模态波,是模态声发射分析的有力方法.

ACOUSTIC EMISSION CHARACTERISTICS OF RUB-IMPACT FOR ROTOR-BEARING SYSTEM BASED ON WAVELET SCALOGRAM

Rub-impact between the rotor and the stator in the rotor-bearing system will cause elastic strain in the rubbing location and thus can produce acoustic emission. Therefore, such acoustic emission can be used to identify and diagnose the rub-impact fault. Analyzing the acoustic emission characteris-tics of the rub-impact in the rotor-bearing system is emphasized by the experiment. At first, in light rub-impact situation, the acoustic emission and the vibration signal are compared and analyzed to demonstrate the superiority of the acoustic emission based method for the rub-impact identification. Then, the wavelet scalogram is introduced in detail and its characteristics are illustrated through simulation. Finally, the specific experi-ments are performed. And the wavelet scalogram is used to analyze and discuss the time-frequency features, propagation characteristic and frequency dispersion characteristic of the rub-impact acoustic emission. The results reveal that the rub-impact acoustic emission is the multi-modal elastic wave which mainly includes the flexural wave and extensional wave. It is also indicated that the wavelet scalogram is the strong analysis method for the wave analysis of the modal acoustic emission.