Research on interfacial delamination damage identification of GFRP‑reinforced laminates based on vibration transmissibility

The interlayer interface is the weakest region of fiber-reinforced composite laminates, and interfacial debonding and delamination are the dominant forms of interfacial damage of GFRP structures in service. Interfacial bonding state directly governs the dynamic mechanical properties and vibration transmission performance of laminates. This paper proposes a damage identification method based on vibration transmissibility to accurately locate interfacial delamination of GFRP laminates. First, vibration excitation experiments of damaged laminates were conducted to collect acceleration response data. Then, the transmissibility function was established, and a damage index TD was constructed via L1 norm normalization. The influence of delamination position and damage severity on TD was analyzed. The results indicate that the index TD matches well with actual interfacial damage distribution. This work provides an effective monitoring method for interfacial damage evaluation and offers theoretical support for performance optimization and safe engineering application of GFRP composite structures.