Numerical simulation of compact-tension specimens repaired by CFRP

Carbon fiber reinforced polymer (CFRP) reinforcement is emerging as an efficient means of elongating the service life of cracked metallic structures. An experimental program was conducted to investigate the fatigue behavior of compact-tension (CT) specimens repaired by different CFRP configurations. In parallel, numerical simulations of the fatigue crack growth in the CFRP-repaired specimens were also conducted. The eXtended finite element method (XFEM) was employed and shown to provide accurate and efficient calculations of the stress intensity factor (SIF), without remeshing the models during crack propagation. The mechanical properties of the adhesive were simulated using a cohesive traction-separation relationship. Good agreement was observed between the numerical and experimental results of the SIF and fatigue life, with the latter numerically predicted based on the experimentally derived Paris law constants. Insight into the debonding behavior between the CFRP and steel specimens has also been provided. Due allowance for the weakening effect of damage initiation and evolution between the FRP-steel interfaces is required in the reinforcement calculations.