Study on Mode I interlaminar fracture behavior of automated fiber placement in situ consolidation thermoplastic composite considering the influence of roller compaction pressure

Abstract This study delved into the Mode I fracture behavior of laser‐assisted automated fiber placement (AFP) in situ consolidated thermoplastic composite laminates under different curing pressures. In compliance with ASTM D5528 standards, T700 carbon fiber reinforced polyether ether ketone (T700‐CF/PEEK) double cantilever beam (DCB) specimens were fabricated and segregated into three test groups subjected to distinct roller pressures: DCB‐100N, DCB‐500N, and DCB‐1500N. The fracture toughness of these specimens was then inversely characterized by employing an optimized ASTM‐based data reduction methodology. A kind of tri‐linear cohesive zone model (CZM) incorporating the fracture process zone (FPZ) length was developed to simulate delamination behavior, showing good agreement between experimental results and simulation predictions. Compared with the other two test groups, DCB‐1500N specimens have more inter‐laminar bridging fibers and higher propagated toughness. Although the length of fiber bridging area is shorter, the fiber bridging density is higher, so the influence of fiber bridging on toughness is more pronounced in the DCB‐1500N specimens. This study provides theoretical guidance for the impact resistance design of thermoplastic composites (TPCs), offering valuable insights into the intrinsic relationship between material processing and fracture damage mechanisms. Highlights Explore the characteristic interlaminar fracture behavior of thermoplastic laminates made by AFP under different curing pressures. Develop a more accurate tri‐linear CZM model to describe the plastic deformation at crack tips and fiber bridging during the delamination process. Unveil the intrinsic relationship between AFP curing pressure and ductile fracture mechanism of thermoplastic composites.