Abstract
As a simple repair technique for steel members suffering from corrosion attacks and fatigue damages, bonding patch plate have been used. In the patch plate bonding repair, the prevention of delamination of patch plate is one of the main concerns. Therefore, some verification is strongly required to prevent the delamination of patch plate. For the evaluation of brittle failure like debonding, the energy release rate is often used. However, the energy release rate previously proposed does not take into account the delamination mode I and II. In this study, mode I/II energy release rates by using normal and shear stresses in adhesive layer are derived for cracked steel plate repaired with patch plates on both side. By using high accuracy solution of normal and shear stresses in adhesive layer, both energy release rates almost agree with the results of FEM analysis.
