高温环境下碳纤维增强树脂复合材料的层间力学性能老化行为与失效预测

为了研究碳纤维增强树脂(CFRP)复合材料层间力学性能在高温环境中的老化失效行为,设计了CFRP复合材料层间拉伸和层间剪切实验,在高温(80℃)环境中进行0(未老化)、 120 h、 240 h、 360 h、 480 h、 600 h和720 h的老化测试,分析CFRP层间失效强度和失效形式随老化时间的变化规律,得到随高温老化的二次应力准则响应面。建立CFRP复合材料层间力学性能预测模型,得到不同老化衰减系数下的退化模型,并通过CFRP复合材料层间仿真模型进行了验证。结果表明:随着高温老化时间的增加,层间拉伸和层间剪切强度总体上都发生了一定程度的退化,层间拉伸时更容易发生碳纤维丝剥离,层间剪切发生局部的树脂剥离,纤维之间的分层更加明显,高温老化使树脂与纤维丝的界面结合力显著下降。通过CFRP复合材料层间力学性能随高温老化的二次应力准则,计算不同老化时间后的内聚力模型参数,预测CFRP复合材料在高温老化条件下的层间强度,发现仿真与实验误差小于10%,说明了CFRP复合材料层间失效预测模型的准确性。

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.