Voids detection in bonded metal/composite or concrete/composite assemblies using acousto-ultrasonic method: contribution of simulation

The present work aims at studying voids detection in bonded metal/composite or concrete/composite assemblies using numerical simulations of Acousto-Ultrasonic (AU).The assemblies are made of a steel or concrete substrate and a unidirectional composite laminate bonded with an epoxy adhesive.This study allows assessing experimentally and numerically the sensitivity of AU technique to voids within the joint.Three-dimensional FE models are developed to simulate the influence of voids and sensor location on the recorded signal.Both the relative location of the sensor with respect to the defect epicentre and the kind of receiver sensor are thus fundamental for defect detection.The proposed model enables determining the parameters affected by the size of the defect (such as e.g., amplitude and frequency centroid) and an analysis based on the relevant parameters increases the probability of detection of voids.