Prediction of Creep Behaviour of the Hybrid Composite Material Using the Accelerated Characterisation Method

Abstract

We present in this study a creep behavior in flexure of a hybrid composite consisting of a polyester matrix containing methyl methacrylate reinforced by two bidirectional fabrics. The first one is made with E-glass fibers and the second one is made of a knitted polyamide 66. The mass fractions are 13% for the glass fabric and 9% for the polyamide fabric. The specimens, of dimensions (L = 60, l = 15 and h = 2.3 mm) containing 06 alternating layers (2P/2V/2P) were fabricated by using the vacuum bag molding method. Bending tests performed at different temperatures allowed us first to determine the load levels for the creep tests. Creep tests at different loads (5 to 43 MPa) and different temperatures (23 ° to 80 ° C) show a noticeable increase of creep deformation for both tests under the same load and different temperatures just as those carried out at different loads under the same temperature. The initial deformation varies significantly with the load but very little with temperature. The application of the Findley model shows good correlation with experimental results. Model parameters were identified. Creep deformation satisfies the principle of superposition time-temperature-stress (TTSSP). Findley's model has subsequently been coupled with the principle of superposition of time-temperature-stress to plot master curves at different stresses and temperatures; this enables prediction of creep deformation in the long term.

On the use of the stepped isostress method in the prediction of creep behavior of polyamide 6

“…Among others, Hadid et al [9] have used this approach to predict the long-term material creep behavior of the injection fiber glass reinforced polyamide, an improved empirical model (power law) is used and an excellent superposition of curves is obtained. Based on both temperature and stress effects, a novel approach called Time Temperature Stress Superposition concept (TTSS) is invented thereafter to reduce abundance of samples and to get more accurate results [11,12]. This last one remains very complex, even though it overcomes the negative heat impact and the samples abundance.…”