Surface fatigue crack propagation behavior of CFRP-steel plates with improved J-integral driving model

This study presents an experimental investigation into fatigue surface crack propagation behavior of CFRP (Carbon Fiber Reinforced Polymer) reinforced steel plates under cyclic load. The investigation employs the beach marking method and digital image correlation (DIC) methods to measure crack propagation with CFRP covering. CFRP has a significant influence on crack propagation rate, with an approximately 40% improvement in the length direction, while only a negligible 10% improvement is observed in the depth direction. The crack propagation rule is expressed using the improved J-integral driving model which can be expressed as a power function in two directions. Both CFRP and crack length noticeably influence the coefficient parameter in Paris formula, while the parameter index is only affected by crack depth. The crack propagation predictive model was found to be accurate compared to the experimental results.