Nondestructive Testing for Composite Materials: Methods, Challenges, and Future Outlook

Composite materials offer superior specific properties, enabling improved efficiency and cost-effectiveness across a wide range of industries. To ensure safety and reduce maintenance costs, these structures require reliable non-destructive testing (NDT) for effective structural health monitoring (SHM). Various NDT techniques-including microwave sensing, ultrasonic testing, acoustic emission, guided waves, thermography, optical methods, and eddy current testing-are employed to detect deformations, cracks, flaws, and other defects in carbon- and glass-fiber-reinforced polymer composites. This work examines the operational principles, historical evolution, standard procedures, instrumentation, and performance of these methods, highlighting their respective strengths, limitations, and suitability for different defect types. Comparative analysis is provided to identify the most appropriate techniques for specific SHM scenarios. Finally, future trends are discussed, emphasizing automated, intelligent inspection systems with enhanced accuracy, data processing capabilities, and integration potential for next-generation composite monitoring solutions.