Transverse matrix cracking is probably the first and most dominant mode of damage in composite materials. In this paper, a real-time Non-Destructive Testing (NDT) method was proposed to detect the transverse cracks by Fiber Bragg Grating (FBG) sensors. The experiment of observing the crack growth and recording FBG’s reflection spectrums as well as Finite Element Method (FEM) methods were conducted to help verifying the regularities of the reflection spectrum distortions in the cracking angle-ply [0 n / ± θ m /0 n ] laminates. The results showed that the shape of the spectrum was highly correlated to the crack density of composites. From undamaged state to high crack density conditions, the shape of the spectrum experienced an ‘original-splitting-regressive’ process. Under the assumed ideal periodic strain distribution conditions, the peak width w of the reconstructed spectrums and crack density $$\rho$$ ρ showed very good linearity which provided the possibility for quantitative detection of the crack density of composites.

中文翻译：

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基于FBG传感器光谱的复合材料横向基体裂纹实时无损检测方法

横向基体开裂可能是复合材料中第一种也是最主要的损伤模式。在本文中，提出了一种实时无损检测（NDT）方法来检测光纤布拉格光栅（FBG）传感器的横向裂纹。通过观察裂纹扩展和记录FBG反射光谱的实验以及有限元法（FEM）方法来帮助验证裂纹角层[0 n / ± θ m /0 n ] 层压板。结果表明，光谱的形状与复合材料的裂纹密度高度相关。从未损坏状态到高裂纹密度条件，光谱的形状经历了“原始-分裂-回归”过程。在假设的理想周期应变分布条件下，