A two-step impact localization method for composite structures with a parameterized laminate model

External impacts have serious harm to fiber reinforced composite laminates, because Barely Visible Impact Damage (BVID) may happen, which reduces strength and stiffness of laminates. In this paper, an impact monitoring method is proposed to locate impacts for composite laminates based on a parameterized laminate model. The method is divided into two steps: (1) inverse material parameters by two impacts with known locations, which is called the calibration step. This step can be used to calibrate material parameters before actual applications of structures, or regularly as required to ensure the accuracy of impact localization. (2) Inverse impact locations when the material parameters are known, which is called the monitoring step. The arrival time of flexural waves extracted by continuous wavelet transforms is used as input features during the inverse process. A multi-frequency localization technique is adopted to overcome the inaccuracy of measurements of arrival time at certain frequencies. Finally, the proposed method with sufficient accuracy of impact localization is verified by experiments on a unidirectional laminate.