大尺寸三维编织复合材料结构损伤指数特征

Damage index characteristics of large-size 3-D braided composites

为实现大尺寸三维编织复合材料内部损伤实时监测,针对三维六向编织复合材料的编织特点,将布拉格光栅(FBG)传感器嵌入三维编织复合材料预制件中,提出了大尺寸智能复合材料的制作方法。研究了大尺寸复合材料内部FBG传感器的拉伸特性,基于主成分分析方法提出了制件结构损伤检测算法,分析了相同损伤的4个制件的损伤指数表现特征。试验结果表明:FBG传感器能准确测量复合材料内部损伤变化;损伤指数可描述试件结构损伤程度。损伤指数T2和综合损伤指数Phi能迅速诊断制件内部损伤的存在性,对于制件的同一个损伤Phi指数计算值大于T2指数值,是其2倍以上,Phi指数可用于及时判断制件内部是否产生损伤,Q指数和I指数描述损伤的详细参数更加准确。

In order to study the real-time monitoring of the internal damage of large-size 3-D braided composites,the fiber Bragg gratings(FBG)sensors were embedded in the 3-D braided composite preform according to the braiding characteristics of 3-D six-directional braided composites.A method for producing large-size intelligent composite materials was proposed.The tensile characteristics of the FBG sensor inside the composites was studied.Based on the principal component analysis method,the damage detection algorithm of the specimen structure was proposed.The damage index performance characteristics of the four samples with the same damage were analyzed.The experimental results show that the FBG sensor can accurately measure the internal damage of the composite.The damage index can describe the damage degree of the specimen structure.The T 2 index and Phi index can diagnose the occurrence of internal damage of the specimens more quickly.For the same damage of the sample,the Phi index is calculated to be more than 2 times of the T 2 index,and the Phi index can be used to judge whether the interior of the sample is damaged in time.Q index and I index describe the details of the damage more accurately.