一种新型低温光纤环声发射传感技术

A new acoustic emission sensing technology of fiber-optical ring using in low temperature

为解决当前低温声发射检测技术无法对声发射信号进行时差定位的问题,介绍了一种光纤环声发射检测技术。通过理论分析初步构建了光纤环声发射传感器的理论模型,基于光纤马赫-曾德干涉原理搭建了四通道光纤环声发射传感器样机,开展了低温钛合金气瓶液氮环境下的平面定位和声发射检测灵敏度初步测试。试验结果表明,研制的光纤环声发射传感器能够在低温环境下直接耦合气瓶进行声发射信号采集与定位,信号采集灵敏度不低于90 dB,四通道平面定位偏差最大不超过最大传感器间距的8%,为后续光纤环声发射检测技术的工程化应用奠定了一定基础。

To overcome the difficulty in signal localization of acoustic emission(AE) detection in low temperature, the technology of fiber-optic ring(FOR) AE was introduced in this article. The theoretical model of FOR AE sensor was built by theoretical analysis. The four-channel FOR AE equipment was built base on the theory of Mach-Zehnder interference. The performance of the FOR AE equipment in low temperature was analyzed thought the AE tests of typical titanium cylinder in low temperature. The results demonstrate that the FOR sensor can be directly coupled on the cylinder in low temperature for AE detection, the average signal amplitude can reach 90 dB;The AE signals can be located by using four-channel FOR AE equipment, the signal location deviation will not exceed 8% of the maximum sensor spacing. This will lay a certain foundation for the application of FOR AE detection in engineering.