A study on the failure mechanisms of carbon fiber/epoxy composite laminates using acoustic emission

The complex failure mechanisms that are commonly considered as the distinctive characteristic of composites are being amenable to nondestructive test advance. This research adopts the acoustic emission technique to study the failure mechanisms and damage evolution of carbon fiber/epoxy composite laminates. Effects of different lay-up patterns and hole sizes on the acoustic emission response are studied to set up the mapping between the failure properties and the acoustic signal features such as the energy, counting and amplitude. Moreover, the microscopic properties of different composite specimens after fracture are watched and analyzed by scanning electron microscope (SEM). Based on the mapping conception, the controlling microscopic failure mechanisms of composites including the splitting matrix cracking, fiber/matrix interface debonding, fiber pull-out and breakage as well as delamination are identified. It is expected the influence of complex lay-up patterns and sizes on the damage and failure properties of composites is represented by creating true mapping based on the acoustic emission technique.

► The failure mechanisms of composite laminates are studied by acoustic emission.
► The mapping relationships between the acoustic response and failure modes are obtained.
► The dominating failure mechanisms of composites are identified by acoustic amplitude.