Analytical model and spectral characteristics of acoustic emission signal produced by localized fault of rolling element bearing

The accurate description of acoustic emission signals produced by the localized fault of a rolling element bearing plays an important role in its feature extraction and analysis. This paper analyzes the excitation mechanisms and develops the analytical model of acoustic emission signals produced when the rolling element bearing passes across the localized fault on the inner or outer race. Based on the analytical model, the spectral characteristics are discussed substantially. Simulations and experiments are carried out to validate the efficacy of the model developed in the paper. The experimental results show that the response signal thus produced has two parts. The first one is produced by the entry of the rolling element bearing, while the other is produced by the departure of the rolling element bearing. The energy of both parts is concentrated around the resonance frequency of the acoustic emission transducer. Generally, the interval of adjacent acoustic emission events is not equivalent to each other and the corresponding spectrum is continuous in the high frequency band. 准确描述故障信号是进行滚动轴承故障特征提取与分析的基础。深入分析了滚动体通过轴承内、外圈局部故障时产生声发射信号的机理，建立了含双冲击响应的声发射信号解析模型，并探讨了声发射信号的频域特征。采用仿真信号与试验信号验证了解析模型的正确性。结果表明：滚动体通过局部故障时会产生与进、出故障相关的2个声发射事件，且2个事件的响应能量均集中在传感器共振频率附近；声发射信号功率谱由低频段的离散谱和高频段的连续谱共同组成。