Research and prediction of creep behavior of triaxial warp-knitted composites by time–temperature equivalent principle

Abstract

In this paper, the creep behavior of triaxial warp-knitted composites (TWKC) was investigated. The TWKC specimens were prepared by applying vacuum-assisted resin infusion (VARI), and the three-point bending creep experiments at different temperatures were carried out. The shift factor was calculated based on the activation energy method, and the creep curve at 25°C within 105s was obtained according to the time–temperature equivalence principle, the time–temperature equivalent model was established, and the model was verified by measuring the long-term creep data with self-made instrument. There is approximately agreement between the prediction result and experimental one, which is less than 10% within 105s. The results show that the model could be used to predict the creep behavior of TWKC. The viscoelastic properties of the specimen were analyzed based on dynamic mechanical analysis (DMA), and the creep behavior of TWKC was further analyzed by acoustic emission and digital image correlation damage analysis. Highlights: The viscoelasticity of TWKC was analyzed based on dynamic mechanical analysis (DMA), and the activation energy was calculated. Based on the activation energy method, the time–temperature equivalent model was established to predict the creep behavior of TWKC. The creep behavior of TWKC were further analyzed by acoustic emission (AE) and digital image correlation (DIC) damage analysis.