Glass Fiber Reinforced Polymer (GFRP) composites have been widely used in advanced engineering applications, mainly in the automotive and aerospace industries. Due to its anisotropic nature, the damage and failure detection in composites under real-time loading are very complicated. Focusing on this problem, Multi-Walled Carbon Nanotubes (MWCNTs) based strain sensor for Structural Health Monitoring (SHM) of Fibre Reinforced Polymer (FRP) composites is proposed in this research. This study primarily aims to detect induced flexural strains and damages occurring in the composites in real-time for which glass fibers coated with carboxy and amide functionalized MWCNTs have been used as sensors. The interactions between MWCNTs and fiber surface were confirmed with FTIR. Carbon fiber sensors have been used for comparison. The sensors were embedded into GFRP composites which were subjected to three-point bending tests coupled with electrical resistance measurement to correlate the induced strain and damages with the fractional change in resistance across sensors. The electromechanical test results indicated that MWCNT coated sensors in GFRP composites show promising piezoresistive sensing characteristics with good cyclic reproducibility that is significant for in-situ strain monitoring and damage detection. Overall the highest strain sensitivity was observed with amide functionalized MWCNT sensors. The electrical response to temperature cycles showed a reproducible behavior with −8% relative resistance change within the temperature range of −10 °C to 80 °C which also signifies multifunctional characteristics of developed sensors.

玻璃纤维增​​强聚合物（GFRP）复合材料已广泛用于高级工程应用中，主要用于汽车和航空航天行业。由于其各向异性，实时载荷下复合材料的损坏和失效检测非常复杂。针对这一问题，本研究提出了基于多壁碳纳米管（MWCNTs）的应变传感器，用于纤维增强聚合物（FRP）复合材料的结构健康监测（SHM）。这项研究的主要目的是实时检测复合材料中产生的弯曲应变和损伤，为此，已将涂覆有羧基和酰胺功能化MWCNT的玻璃纤维用作传感器。FTIR证实了MWCNT与纤维表面之间的相互作用。碳纤维传感器已用于比较。传感器嵌入到GFRP复合材料中，该复合材料经过三点弯曲测试和电阻测量，以将感应应变和损伤与传感器两端电阻的分数变化相关联。机电测试结果表明，GFRP复合材料中的MWCNT涂层传感器显示出良好的压阻传感特性，并具有良好的循环再现性，这对于原位应变监测和损伤检测非常重要。总体上，使用酰胺官能化的MWCNT传感器观察到了最高的应变敏感性。对温度循环的电响应显示出可再现的行为，在-10°C至80°C的温度范围内，相对电阻变化为-8％，这也标志着已开发传感器的多功能特性。