Effect of longitudinal interfacial defects on fracture energy variation
in DCB bonded specimens
Abstract
The primary aim of this investigation is to develop an analytical
technique that can accurately estimate the fracture energy at the crack
front while accounting for the localized interface properties. To
achieve this goal, the study employs Double Cantilever Beam (DCB)
specimens made of Aluminium alloys that have been chemically treated, as
well as Titanium alloys that have been Laser texturized. Additionally,
longitudinal defects are introduced within the bond line, specifically
at the interface between the adhesive and adherents, with a parallel
orientation to the crack direction. Initially, the investigation
involved the characterization of bare surfaces, independent of their
adhesive strength. Subsequently, Double Cantilever Beam (DCB) tests were
conducted on specimens that had defects of various widths in the bonded
region. The results obtained from these experiments confirmed the
accuracy of the analytical estimations. It has been explained too that
adhesive stiffness has a major role while mixing local fracture energies
at crack front. Additionally, using a damage model, the deformation of
the crack front was numerically observed and verified by capturing crack
front shape while DCB testing. An interpretation was provided to explain
the findings.