SHM OF LARGE STRUCTURES USING GUIDED WAVES FOR CRACK DETECTION

Guided ultrasonic waves offer an efficient way for the long‐term integrity monitoring of large structures. Permanently attached distributed or localized sensor arrays have been shown to be able to detect and localize simulated corrosion damage. Crack‐like defects have a directivity pattern of the scattered field, which must be taken into account for the data processing algorithm. The directivity pattern of the scattered field for the A0 Lamb wave mode has been predicted from 3D Finite Element simulations and verified from experimental measurements at machined part‐through and through‐thickness notches. These results provide the basis for the quantification of the detection sensitivity for defects in plate structures using guided wave arrays. Using a hybrid model to account for the propagation distance and scattering characteristics, the relative amplitudes of received pulses for given sensor locations can be calculated. From a comparison with the signal to noise ratio of the array system, detection capabi...