Aging behavior and failure prediction of interlaminar mechanical properties of carbon fiber reinforced polymer composite at high temperature

In order to study the aging failure behavior of interlaminar mechanical properties of carbon fiber reinforced polymer (CFRP) composite in high temperature environment, the interlaminar tensile and shear tests of CFRP composite were designed. Aging tests were carried out for 0 (unaged), 120 h, 240 h, 360 h, 480 h, 600 h and 720 h at high temperature (80℃). The variations of interlaminar failure strength, failure stiffness and failure mode of CFRP composite with aging time were analyzed. Secondary stress criterion response surface with high temperature aging was obtained. A prediction model of interlaminar mechanical properties of CFRP composite was established, and a degradation model based on aging attenuation coefficient was obtained, which was verified by CFRP composite interlayer simulation model. The results show that with the increase of aging time at high temperature, the interlaminar tensile strength and shear strength are degraded to a certain extent. It is easier to peel off carbon fibers during interlaminar tension, and local resin peeling occurs during interlaminar shear. The interlaminar delamination between fibers is more obvious. The interfacial bonding force between resin and fibers decreases significantly due to high temperature aging. According to the secondary stress criterion of CFRP composite interlaminar mechanical properties aging with high temperature, the cohesion model parameters after different aging time were calculated. The interlaminar strength of CFRP composite under high temperature aging condition was predicted. It is found that the error rate of simulation and experiment is less than 10%, which shows the accuracy of CFRP composite interlaminar failure prediction model.