Stone impact damage identification in composite plates using modal data and quincunx wavelet analysis

Low-velocity impact damaging of the composite structural elements is an important problem during machine's operation, especially in the aircraft and aerospace industries. Thus, appropriate nondestructive structural diagnostics methods should be developed in order to identify the damages in possible early stage of their development. The paper deals with the experimental study of impact damage identification of composite structures subjected to the low-velocity impacts by stones. The proposed damage identification algorithm is based on the modal analysis of damaged structures and further wavelet analysis of acquired modal shapes using nonseparable quincunx wavelets. The analysis was performed for the composite structures typical for those used in the aeroplane sheeting impacted with various energies. The application of quincunx wavelets allows for accurate localization of the damages and for avoiding the boundary effect occurred during an application of separable wavelets. Obtained results show the efficiency of the proposed method and could be used in industrial applications as well.