光纤光栅声发射检测新技术用于轴承状态监测的研究

摘要

The health state of a bearing has a tremendous influence on a rotating machinery.A failing bearing can not only jeopardize the safety of flight but also induce collateral damages.It is necessary to monitor and judge the tiny earlier fault in an effective way.Compared with the conventional vibration detection approach,acoustic emission (AE) can be used to detect the earlier state of the fault,and diagnose the fault type and damage level.Here,the detecting principle of rolling bearing fault with AE and the novel AE detection technique using a fiber Bragg grating (FBG)were introduced.A comparative experimental study with FBG sensor and the commercial PZT-based transducers was conducted to detect a precut defect on the outer race of a rolling bearing.The experimental and analysis results showed that the detected signals with FBG have better spectra than those using PZT with clearer lines and lower noise,the fault frequency and damage level can be more easily identified.Finally,the applications of this technique in helicopter maintenance were introduced.%轴承的健康状况对旋转机械的工作状况有极大的影响。航空器中的故障轴承会间接造成事故，给飞行安全带来灾难性的后果，需要进行早期故障的有效检测判别或状态监测。与振动等传统的检测手段相比，声发射可有效检测到故障的早期状态，准确判断故障类别和严重程度。介绍了滚动轴承故障声发射检测原理以及光纤光栅声发射检测新技术。以预制外圈缺陷的轴承为例，进行了压电式声发射传感系统和光纤光栅声发射传感系统检测的对比实验，实验和分析结果表明光纤光栅声发射方法检测到的信号谱底噪声小，谱线清晰、干净，更容易分辨故障频率和分析故障的严重程度，优于振动和压电式声发射传感方法。最后介绍该技术在直升机维修保障中的应用情况。