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针对传统冲击监测系统存在无法定位多源冲击、组网难和精度低等问题,设计了一种基于光纤Bragg光栅(FBG)传感网络和时间反转聚焦成像冲击定位方法。在分析时间反转聚焦成像定位原理的基础上,建立由4个FBG组建的传感网络监测系统,通过窄带激光边缘滤波实现信号解调。利用Shannon小波变换提取特定频率的窄带信号,并计算信号模值及速度。通过建立时间反转聚焦模型实现多源冲击搜索定位及成像,并在监测区域为400mm×400mm的航空铝合金板结构上进行验证。结果表明,本文方法可实现冲击定位,定位误差小于15mm,为冲击监测提供了一种新的高精度方法。
Aiming at the problems that traditional impact monitoring system can not locate multi-source impact, difficult networking and low accuracy, a method based on fiber Bragg grating (FBG) sensing network and time-reversal focused impact imaging is proposed. On the basis of analyzing the principle of time-reversal focusing imaging, a sensing network monitoring system built by 4 FBGs is established, and the signal demodulation is realized by narrow-band laser edge filtering. The Shannon wavelet transform is used to extract the narrow-band signal of a specific frequency, and the signal modulus and speed are calculated. The multi-source impact search location and imaging are achieved by establishing the time-reversed focusing model and verified on the aviation aluminum alloy plate structure with a monitoring area of 400mm × 400mm. The results show that the proposed method can achieve impact localization and positioning error less than 15mm, providing a new high precision method for impact monitoring.