ABSTRACT

To further promote the use of composite bonded structures in engineering applications, it is necessary to understand the change law of the fatigue performance in the long-term server process. This paper investigated the effect of temperature and humidity on the fatigue behaviour of adhesively bonded CFRP/aluminium alloy joints using an experimental method. The quasi-static tensile and fatigue tests of CFRP/aluminium alloy butt joints were carried out at 20 °C, 40 °C, 60 °C and 80 °C, as well as at different ageing times of the 60 °C/95% RH hygrothermal environment. The results demonstrate that with increasing test temperature, the fatigue performance of the adhesive joints decreases substantially, especially when the temperature is close to or higher than T_g of the adhesive (similar to the static failure strength). In the 60 °C/95% RH environment, the fatigue performance of the joint decreases as the ageing time increases, and the fatigue strength decreases more obviously in the early ageing stage. In the single logarithmic coordinate system, the S-N curves at different temperatures/ageing times both conform to the linear law. The function of the stress-temperature/ageing time-number of the cycles to failure was established to help understand the influence law of the environment on the fatigue characteristics of joints and provide a reference for the prediction of the fatigue performance of adhesively bonded joints exposed to a hygrothermal environment.

摘要

为进一步推动复合粘结结构在工程应用中的应用，有必要了解长期服务过程中疲劳性能的变化规律。本文采用实验方法研究了温度和湿度对 CFRP/铝合金粘合接头疲劳行为的影响。CFRP/铝合金对接接头的准静态拉伸和疲劳试验分别在20℃、40℃、60℃和80℃以及60℃/95%的不同时效时间下进行RH湿热环境。结果表明，随着试验温度的升高，胶接接头的疲劳性能显着下降，尤其是当温度接近或高于_Tg时粘合剂（类似于静态破坏强度）。在60 ℃/95% RH环境下，接头的疲劳性能随着时效时间的增加而降低，且在时效早期疲劳强度下降更为明显。在单一对数坐标系下，不同温度/老化时间的SN曲线均符合线性规律。建立应力-温度/老化时间-失效循环次数函数，有助于了解环境对接头疲劳特性的影响规律，为外露胶接接头的疲劳性能预测提供参考。到湿热环境。