Simulation on the mechanical performance and fracture behavior of unidirectional carbon fiber-reinforced composites

Unidirectional carbon fiber reinforced polyamide 6 (CF/PA6) laminates after tensile tests exhibited two different types of fracture modes, namely, splitting and step-like. In this study, the mechanical properties and fracture behavior of the unidirectional CF/PA6 laminates were simulated and analyzed by using finite element simulation of a tensile test. The simulations considered the actual deformation and damage mechanism (matrix plastic deformation, stochastic fiber fracture, and interfacial debonding between the fiber and the matrix) experimentally observed in previous research. Results of the numerical simulations were in good with the experimental stress–strain curves. Moreover, the above-mentioned two types of fracture mode were well simulated by changing the interfacial properties. The simulated results showed that the unidirectional laminates with weak interface properties exhibit the splitting fracture mode. Meanwhile, the unidirectional laminates with strong interface properties show the step-like fracture behavior.