Quantitative defect inspection in the curved composite structure using the modified probabilistic tomography algorithm and fusion of damage index.

The curved composite structures are popularly used in the aerospace field for their superior properties. Complexity of structure and geometry generally limit the inspection or monitoring effect of different types of defects in the curved composite structure. A feasible damage probabilistic tomography algorithm combined with ultrasonic guided wave technology is necessary to be developed for the structural health monitoring of curved composite structures. In this paper, defect zones in a curved composite structure are characterized using the modified probabilistic tomography (MPT) method and fusion of damage index (DI). The MPT with the defect shape factor β at each damage-impaired path and hybrid DI schemes are proposed to indicate the location and propagation of defect zones in tested sample. The feasibility of proposed approaches is verified on the curved carbon/epoxy composite structure, experimentally. The results show that the MPT and fusion DI methods successfully represent the extension of defect zones in a quantitative manner. It is suggested that the accuracy and reliability of localization results of the MPT algorithm is better than those obtained by the probabilistic tomography (PT) algorithm with the averaged β.