REQUIRED LENGTH OF CFRP FOR CFRP BONDED STEEL TUBES AND ENERGY RELEASE RATE FOR DEBONDING

Abstract

 In this study, stresses in the CFRP bonded steel tube under tensile or pure bending conditions by applying the shear lag theory are derived. The stresses in the steel tube and CFRP and the shear stress in the adhesive layer were in good agreement with that calculated by the finite element method. The required length of CFRP for CFRP bonded steel tubes can be calculated by the stress distribution in the steel tube. Additionally, it was shown that the stress intensity factors calculated by the shear stress in adhesive given by the shear lag theory under tensile or pure bending conditions show the same tendency as that given by the finite element method. Additionally, it was clarified that the stress intensity factors calculated by the strain energy of CFRP bonded steel tubes were also derived and they are corresponding with that given by the shear stress in the adhesive layer.