基于FBG非均匀反射谱特性的波纹型复合材料蒙皮渐进损伤监测

Progressive Damage Monitoring of Corrugated Composite Skins by the FBG Spectral Characteristics

提出利用布拉格光纤光栅(FBG)非均匀反射谱监测复合材料结构渐进损伤的方法。对波纹型复合材料蒙皮样件进行有限元分析,预测蒙皮在拉伸载荷下失效过程和对应临界失效载荷大小,据此重构FBG传感器的非均匀反射谱,获得铺层失效与传感器反射谱的对应关系,并为实验光谱记录提供参考。构建一种基于FBG非均匀反射谱监测波纹型复合材料蒙皮渐进损伤的监测系统,进行拉伸实验,实验结果表明系统实测光谱与重构的反射谱趋势相同,对应失效载荷与预测值最大误差为8.6%,证明了采用FBG传感器监测波纹型复合材料蒙皮渐进损伤的可行性。该方法通过实时监测预测失效范围内FBG非均匀反射谱的变化,简单易行,测量及传导光路实现全光纤化,无需破坏试件结构,即可实现对波纹型复合材料蒙皮渐进损伤程度及铺层失效次序精确、迅速的在线监测,研究结果为智能蒙皮动态监测领域提供新的思路和实验参考。

In the present paper, a method of monitoring progressive damage of composite structures by non-uniform fiber Bragg grating （FINg） reflection spectrum is proposed. Due to the finite element analysis of corrugated composite skins specimens, the failure process under tensile load and corresponding critical failure loads of corrugated composite skin was predicated. Then, the nowuniform reflection spectrum of FBG sensor could be reconstructed and the corresponding relationship between layer failure order sequence of corrugated composite skin and FBG sensor reflection spectrums was acquired. A monitoring system based on FBG non-uniform reflection spectrum, which can be used to monitor progressive damage of corrugated composite skins, was built. The corrugated composite skins were stretched under this FBG nonuniform reflection spectrum monitoring system. The results indicate that real time spectrums acquired by FBG non-uniform reflection spectrum monitoring system show the same trend with the reconstruction reflection spectrums. The maximum error between the corresponding failure and the predictive value is 8. 6%, which proves the feasibility of using FBG sensor to monitor progressive damage of corrugated composite skin. In this method, the real-time changes in the FBC- non-uniform reflection spectrum within the scope of failure were acquired through the way of monitoring and predicating, and at the same time, the progressive damage extent and layer failure sequence of corrugated composite skin was estimated, and without destroying the structure of the specimen, the method is easy and simple to op- erate. The measurement and transmission section of the system are completely composed of optical fiber, which provides new i- deas and experimental reference for the field of dynamic monitoring of smart skin.