Creep, Fatigue and Interfacial Durability of CFRP and GFRP Composites: A Critical Review from Experimental and Molecular Dynamics Perspectives

Abstract

Fibre-reinforced polymer (FRP) composites are increasingly used in civil engineering because of their low weight, high strength, corrosion resistance, and good fatigue performance. Among them, carbon FRP and glass FRP are the most widely used types. However, their long-term durability under sustained, cyclic, and environmental effects remains a major concern. This paper presents a brief review of creep, fatigue, and interfacial degradation in CFRP and GFRP. Both experimental studies and molecular dynamics (MD) simulations are considered. Experimental methods, such as creep tests, fatigue tests, fibre pull-out tests, and nanoindentation, are summarized to describe macroscopic behaviour. MD simulations are discussed to explain microscopic mechanisms, including interfacial sliding, moisture-related debonding, and polymer chain relaxation. The results show that CFRP generally has better resistance to creep and fatigue, while GFRP is more sensitive to environmental effects. In both materials, interfacial degradation is a major factor governing long-term failure. This review also links macroscopic behaviour with nanoscale mechanisms and highlights the need for a multiscale approach to improve durability prediction of FRP composites.