Prediction of debonding strength of tensile hybrid bonded joints using fracture mechanics

• A hybrid bonded aluminum/CFRP technology was proposed.
• Nine specimens with and without HB-FRP technique were tested.
• Interfacial stresses of the bond joint were analyzed and tested.
• Analytical model to predict debonding strength was established.

In order to improve the debonding strength of double shear lap (DSL) joints between aluminum plates and carbon fiber reinforced plastic (CFRP) plates, a hybrid bonded fiber reinforced plastics (HB-FRP) technique was proposed in this paper. Debonding strength of the HB-FRP was tested and investigated analytically and numerically. Fracture failure of the aluminum-adhesive interface was identified as the dominant failure mode of the joint. Compared with normal bond joints, the debonding strength of HB-FRP joints can be increased by 71% in experiments. The strain energy release rate (SERR) criterion based on linear elastic fracture mechanics (LEFM) was adopted to estimate the debonding strength of bond joints. Good agreement among theoretical predictions, numerical simulations and experimental data were achieved.