Interfacial cohesive zone model based on atomic potential energy for CFRP

Carbon-fiber-reinforced polymer (CFRP) composites are utilized extensively in aero-engine casings, due to the superior specific mechanical properties and well-developed manufacturing techniques. The interface plays a key role in the macromechanical properties of CFRP. In this paper, an interfacial cohesive zone model (ICZM) of CFRP based on atomic potential energy is proposed, which can accurately characterize the interfacial mechanical behavior of CFRP. Then ICZM is applied to the unit cell model to predict the transverse mechanical behavior and damage evolution of CFRP, and verified by experimental results. The simulation results of the transverse modulus, strength, and ultimate strain for ICZM are 9.62 GPa, 66.87 MPa, and 0.78, respectively. The simulation errors of the transverse modulus, strength, and ultimate strain are all less than 3%, and the simulated damage evolution aligns with the experimental result, validating the precision of ICZM. The research shows that: for the infinite carbon atom layer and epoxy, the shear cohesive stress is zero; for the finite carbon atom layer and epoxy, the shear cohesive stress is much smaller than the tensile cohesive stress; the carbon fiber radius has little effect on cohesive energy; the simulated stress–strain curve for ICZM aligns with experiments, which means that ICZM can reflect the nonlinearity of CFRP. The research result can provide a calculating tool for the structural design of the aero-engine casing.