On the properties and deterioration mechanism of fibre-matrix interfaces of FRP composites under coupled thermal-mechanical actions

Abstract

The kinetic theory is often used to evaluate the long-term performance of fibre-reinforced polymer (FRP) composites. However, the fundamental deterioration mechanism of the fibre–matrix interfaces, which may change significantly with temperature, has not been rigorously examined. This paper presents a study to address this deficiency of existing studies using reactive force field molecular dynamics simulations. Two models were established for the untreated and sizing-treated fibre–matrix interfaces, respectively, and performed debonding simulations over a wide range of temperatures. The simulations were validated with the previous experimental results in various terms and were used to quantitatively examine the effects of coupled thermal–mechanical actions on the key properties of the interfaces and their deterioration mechanism which involves the breakage of covalent bonds. The results shed light on the design and interpretation of accelerated tests and may be used in multiscale and multifield modelling of the durability of FRP composites in the future.