Non-destructive testing and structural health monitoring technologies for carbon fiber reinforced polymers: a review

Carbon Fiber Reinforced Polymer (CFRP), a novel high-performance material, has found extensive use across various domains. Due to the intricate structure of CFRP and variability in its manufacturing process, such as differences in resin curing speeds or carbon fiber alignment, defects including voids and inclusions can inevitably occur. These defects can compromise the material's performance and reliability, making Non-Destructive Testing (NDT) essential for early defect detection and real-time monitoring. This paper reviews existing NDT technologies like visual inspection, computed tomography (CT), ultrasonic testing, acoustic emission testing, infrared thermal imaging, eddy current testing, and Raman spectroscopy. To facilitate performance comparison, we use spider charts to illustrate key aspects of each technique, including detection accuracy, damage localisation, interface details, and online monitoring capabilities. These charts specifically highlight the superior overall performance of CT. The principles, applications, and cutting-edge advancements in NDT techniques and Structural Health Monitoring systems (SHM) are systematically discussed. This review delves into the principles, strengths, and limitations of CFRP damage detection methods, includes detailed examples and provides a selection criterion for the work of NDT researchers.