Measurement of the interfacial strain energy release rate of adhesively bonded structures with metallic substrates before and after water ageing

Abstract

The aim of the presented work is to propagate cracks at interfaces between adhesive joints and metallic substrates and to measure the Strain Energy Release Rate (SERR). In order to propagate at a specific interface and not cohesively, a specific specimen was developed, based on a modification of the Tapered Double Cantilever Beam (TDCB) specimen. In particular, the dimensions of one substrate were reduced to create an asymmetry in the specimen and drive the propagation path towards one interface. The authors present experimental results showing repetitive interfacial failures and a procedure to evaluate the SERR. The non-linear behaviour responsible of non-linear deformation in the substrate was taken into account in the calculations of the SERR. Through a numerical inverse method using Finite Element Analysis (FEA) and Cohezive Zone Modelling (CZM), the SERR was calculated for an epoxy based structural adhesive at the interface with a stainless-steel substrate. Then, the procedure was carried out to measure the interfacial SERR after different ageing times.