Health Monitoring for Composite under Low-Cycle Cyclic Loading, Considering Effects of Acoustic Emission Sensor Type

Composites have been widely used in the aerospace industry. Due to the requirement of a high safety for such structures, they could be considered for health monitoring. The acoustic emission approach is one of most effective methods for identifying damages in composites. In this article, standard specimens were made from carbon fibers and the epoxy resin, with the [03/902/02]s layout. Then, samples were subjected to low-cycle cyclic loading. Besides, signals were recorded with two types of acoustic emission sensors. Obtained results indicated that by increasing the number of cycles and approaching the final lifetime of the sample, the cumulative energy of signals increased. The fracture surface of specimens was analyzed using the scanning electron microscopy. As a consequent and a general conclusion, based on obtained results, it could be claimed that both wide-band and mid-band acoustic emission sensors could be effectively utilized for detecting the defects in composite structures.