Alblalaihid Khalid, Alghamdi Saleh A, Alburayt Anas, Almutairi Saif H, Alwahid Ahmed, Abuobaid Meshal, Alkhibari Sabri, Almutairi Khaled S, Alarifi Ibrahim M
Space and Aeronautics Research Institute, King Abdulaziz City for Science and Technology (KACST), Riyadh 11442, Saudi Arabia.
Department of Mechanical and Industrial Engineering, College of Engineering, Majmaah University, Al-Majmaah, Riyadh 11952, Saudi Arabia.
Sensors (Basel). 2022 Apr 13;22(8):2966. doi: 10.3390/s22082966.
Combining two types of reinforcement fiber in a common matrix may lead to different failure modes such as micro-cracks between the layers when the structure is subjected to lower stress levels. Real-time damage detection should be integrated into the hybrid composite structure to provide structural integrity and mitigate this problem. This paper outlines the working mechanisms and the fabrication of an integrated capacitive sensor in an intra-ply hybrid composite (2 × 2 twill weave). Uniaxial tensile and flexural tests were conducted to characterize the proposed sensor and provide self-sensing functionality (smart structure). The sensitivity and repeatability of the capacitive sensor were measured to be around 1.3 and 185 µΔ/, respectively. The results illustrate that onset of damage between layers can be detected by in situ monitoring. It can be seen that the initial damage was detected at the turning point where the relative change in capacitance begins to reduce while the load increases. Finite element modeling was also constructed to analyze the test results and explain the reasons behind the turning point. It was shown that the carbon yarns experienced high transverse shear stress (τ) in the crimp region, leading to inter-fiber cracks.
在普通基体中结合两种增强纤维可能会导致不同的失效模式，比如当结构承受较低应力水平时，层间会出现微裂纹。应将实时损伤检测集成到混合复合材料结构中，以确保结构完整性并缓解这一问题。本文概述了层内混合复合材料（2×2斜纹编织）中集成电容式传感器的工作机制和制造方法。进行了单轴拉伸和弯曲试验，以表征所提出的传感器并提供自传感功能（智能结构）。测得电容式传感器的灵敏度和重复性分别约为1.3和185 μΔ/。结果表明，通过原位监测可以检测到层间损伤的起始。可以看出，在负载增加而电容相对变化开始减小的转折点处检测到了初始损伤。还构建了有限元模型来分析测试结果并解释转折点背后的原因。结果表明，碳纤维在卷曲区域承受较高的横向剪应力（τ），导致纤维间出现裂纹。
