Effects of thermal aging on damage evolution behavior of glass fiber reinforced composites with multilayer graphene by acoustic emission

Abstract The thermal aging behavior of glass fiber reinforced composites has attracted much attention because of its application in elevated temperatures environments. In this study, to improve the thermal aging resistance performance of composites, multilayer graphene was embedded in glass fiber reinforced composites and the damage evolution behaviors of the composites after thermal aging treatments were investigated. The mapping relationship between damage modes and acoustic emission parameters is established by principal component analysis and k ‐means clustering methods, then the acoustic emission data were trained by K‐Nearest Neighbor algorithms to obtain a damage modes identification model with positive predictive values above 90%. The results showed that more matrix cracking signals are captured (or matrix cracking accumulation acoustic emission (AE) energy is abruptly raised) at the early stage of loading after 32 days of thermal aging. With the addition of multilayer graphene, the fiber/matrix debonding accumulation AE energy is significantly less than the matrix cracking accumulation AE energy, which is more obvious after thermal aging. Damage initiation and extension obtained by the acoustic emission events help to find the correlation between aging time and interior interface damage mechanism.