Debonding strength evaluation in terms of the intensity of singular stress at the interface corner with and without fictitious crack

In this study the debonding strength of adhesively bonded joints is investigated in terms of the intensities of the singular stress fields at the ends of the joints. First, a homogeneous and flawless elastic adhesive layer is assumed to evaluate the butt joint strength for carbon steel/epoxy resin, aluminum/araldite, and brass/solder. It is found that the adhesive strength is always expressed as the critical intensities of singular stress. Next, a small fictitious interface edge crack is assumed at the adhesive layer considering double singular stress fields including and excluding the crack. Then the debonding strength is also found to be controlled by the critical interface stress intensity factor of the fictitious crack. A suitable dimension of the fictitious crack is discussed to predict the strength for adhesive joints accurately and conveniently.