Investigation on creep mechanism of CF/PEEK composite material using molecular dynamics

Abstract

Carbon fiber/Poly ether ether ketone (CF/PEEK) subjects to external loads during service life, high bonding quality of the interface is the key to structural integrity. In order to control the creep slippage of CF/PEEK, explaining the interfacial creep mechanism details are essential. This paper constructs an intercalation model for the CF/PEEK molecular interface and uses molecular dynamics (MD) simulation to demonstrate the evolution mechanism of the interface under different load levels. To verify the effectiveness of the model, the structural morphology, glass-transition temperature, and density of the molecular model were compared with experimental measurements. In terms of interface shear creep, stage Ш creep transitioned from constant to accelerated, the creep curves and corresponding interface microstructure under different stress states were simulated by MD. At the same time, the sliding and debonding processes were explained from an energy perspective. Furthermore, a creep constitutive model was proposed to fit the molecular scale. This study comprehensively interprets the shear creep behavior of the CF/PEEK interface from simulation to constitution.