Strain energy release rate assessment in mode I delamination of foam core sandwich composites by acoustic emission

Abstract

In sandwich structures, delamination along the interface between the face sheet and the core is one of the most common failure modes, and it is often referred to as the adherent or adhesive interface in adhesively bonded joints. The three modes of fracture achieved for delamination are modes I, II, and III, in which mode I is the most critical. Delamination depends on stacking sequence, material properties, the production process, and so on, which are measured by mode I interlaminar fracture energy (G_Ic). In this study, the double cantilever beam test is used to simulate mode I interlaminar fracture and damage evolution through the acoustic emission (AE) method. Based on AE events and the mechanical properties of sandwich composites, the mode I interlaminar fracture toughness, G_Ic, is investigated. The influence of in-plane fiber orientation on the fracture behavior of interfaces is studied and compared with other techniques in ASTM. Consequently, the presented method of employing AEs to obtain G_Ic was determined to be successful.