Damage evaluation of laminated composites under low-velocity impact tests using acoustic emission method

The main goal of this investigation is to characterize the damage in laminated composites under low-velocity impact tests using a new cost-effective approach. To this aim, a quasi-static test was first carried out to obtain initial information about impact tests. Low-velocity impact tests were then applied in unidirectional glass/epoxy composite specimens, and acoustic emission signals were captured during impact events. Next, acoustic emission signals were analyzed using wavelet approach to distinguish released energy related to each distinct damage mechanism. Besides, an approach was provided to estimate threshold impact energy from the quasi-static test, beyond which damage significantly extends. As a final point, the acoustic emission-based procedure using wavelet transform method was proposed to predict the total damage area. Finally, it was found that this acoustic emission methodology can be a capable approach in damage characterization under impact loads in composite structures.