Crack propagation prediction of CFRP retrofitted steel plates with different degrees of damage using BEM

•We modelled the 20 specimens strengthened by CFRP with boundary element method.•We studied the influence of damage degree level on strengthening efficiency.•We gave recommendations on key parameters influencing strengthening efficiency.

Although carbon fibre reinforced polymer (CFRP) materials have proven effective in strengthening steel structures especially when used to improve fatigue behaviour, further study is required to investigate their effectiveness when applied at different stages of crack propagation in steel elements. This paper presents a numerical study on CFRP retrofitted steel plates with different degrees of damage using the boundary element method (BEM). The numerical results compared well with the experimental data, which demonstrated that the BEM is reliable for crack propagation analysis of CFRP laminate retrofitted steel plates. Finally, a parametric analysis was conducted to investigate the influence of bond length, bond width, CFRP stiffness and adhesive shear modulus on stress intensity factor (SIF) values.