Multi-mode damage functions characterization and identification in composite laminates

Composite laminates, prized for high specific strength/stiffness and design flexibility, are critical aerospace materials. However, accidental damage, commonly encountered during service operations, severely compromises their residual structural performance. Precise damage localization and quantitative assessment are vital for structural health monitoring and digital twin systems. Moreover, the inherent multi-layered nature and diverse damage modes create complex, multidimensional damage distributions, challenging accurate identification. This paper proposes a multi-mode damage functions characterization and identification method in composite laminates and constructs a two-stage identification framework synergizing guided wave and vibration principles. Initially, localization of the damage area center and delineation of its boundary are performed using the time-reversal method based on active guided wave signals. Subsequently, employing the improved dual-plane level set damage function (DLSDF) method, the characteristic of in-plane matrix cracking, fiber fracture, and interlayer delamination are established for each layer. By minimizing the residual of passive structural vibration response, achieve comprehensive identification of the location, shape, and severity of in-plane and interlaminar damage. This study validated the accuracy and effectiveness of the proposed method through impact damage identification experiments on composite laminates, thereby demonstrating its robust support for multi-mode damage identification in practical composite engineering applications.