Abstract: This paper presents a new two-dimensional near-field Multiple Signal Classification (MUSIC) damage identification algorithm for damage location of composite structures in structural health monitoring. The wave propagation model is introduced into the proposed MUSIC damage model. The cross-correlation function of residual signals received by experiment and scattered signals received by damage scattering model are developed for spatial spectrum estimation MUSIC algorithm. The spatial spectrum estimation MUSIC algorithm is employed for damage identification of composite structures due to the orthogonality of signal and noise. The numerical example and experiments are employed to demonstrate the validity of proposed MUSIC damage identification algorithm for damage identification with high accuracy and resolution. The proposed damage identification algorithm is further verified for damage identification of aircraft vertical tail. The stiffeners of aircraft vertical tail have great influence on propagation characteristics of guided waves, so the regional damage monitoring strategy is proposed. The experimental results demonstrate the proposed damage identification algorithm is appropriate for complex composite structure.

Key words: composite structures, damage identification, multiple signal classification, guided wave, aircraft vertical tail