Numerical investigation on the fatigue life of non‐cracked metallic plates repaired with bonded CFRP

Abstract

AbstractIn Europe, a large number of old riveted metallic bridges approach the end of their fatigue life. Past research has shown that the application of CFRP can be very efficient in delaying the crack growth rate of deficient structural elements with existing crack. However, little attention is given to the fatigue resistance of non‐damaged metallic members approaching the end of their fatigue life. This is particularly relevant for old metallic riveted bridges, where many critical components do not have existing cracks. This paper presents a numerical investigation on the fatigue behavior of non‐cracked metallic plates bonded with CFRP using epoxy resin. Nonlinear finite element analyses are performed using the commercial software ABAQUS. The cyclic elasto‐plastic behavior and the fatigue strain life of puddle iron metal are obtained from previous experimental results conducted on specimens extracted from Luiz I Bridge (Porto, Portugal). Debonding failure of the adhesive joint is simulated through the use of cohesive zone model with traction separation law. The cohesive behavior was calibrated using fracture mechanic tests results on the adhesive, conducted in a previous related study. The fatigue crack initiation life was estimated using local approach based on material fatigue strain life. Fatigue resistance curves that relate the number of cycles to failure and the applied nominal stress for unreinforced and reinforced elements are derived. The results show that the application of CFRP can significantly increase the fatigue crack initiation life of a metallic structural component significantly.