Damage of Plain Woven Carbon/Epoxy Composite Laminates Subjected to Falling Weight Impact.

Abstract

The progress of damage in perforation impact of plain woven carbon/epoxy laminates was studied using an instrumented falling weight impact testing machine. The thermal deply technique was applied to investigate the three-dimensional distribution of damage such as fiber breakage and delamination at various impact energy levels. The damage process was divided into three different stages according to the growth of main cracks with fiber breakage. In the first stage, surface cracks grew. The second stage was characterized by the propagation of through-thickness cracks. In the last stage, bending fractures of petal shape occurred. In the first and second stages, the absorbed impact energy was found to be a linear function of both the main crack area and the total delamination area. Thus, the contribution of fiber breakage and delamination was determined. The contribution of delamination was unexpectedly large.