The Tilted Sandwich Debond (TSD) Specimen for Face/Core Interface Fracture Characterization

Abstract

A new test specimen, denoted "Tilted Sandwich Debond" (TSD) specimen, for characterization of debond failure of foam core sandwich structure is experimentally examined. The bottom face of a sandwich is attached to an incline, and debond progression is examined under vertical load application to the partially debonded top face. The purpose of the test is to achieve face/core debonding as opposed to crack deflection into the core (kinking). For a sandwich consisting of glass/vinylester face sheets and PVC foam core, a critical angle of the incline, 0 = Oc was identified. When 0 < Oc, it was found that an existing debond kinked into the core. The desired face/core debond failure occurred when 0 > Oc. It was observed that 0C decreases with increasing crack length. The fracture toughness for debonding, expressed as the critical strain energy release rate, Gc, increased with increasing magnitude of the shear component.