ABSTRACT

In real-world applications, adhesive joints are often exposed to the environment and can experience cyclic ageing conditions caused. However, the adhesive response under cyclic ageing is still relatively unexplored. In this study, hygrothermal ageing of an epoxy-based adhesive has been investigated by performing single cycle and cyclic ageing experiments. Different cyclic ageing strategies were followed in this research. In the first strategy the ageing time was set to a constant value and in the second approach, the maximum absorbed water content was limited for each ageing cycle. Absorption and desorption processes for each ageing cycle have been analysed using Fick’s law. This analysis allowed to determine the diffusion coefficients and assess how they are affected by cyclic ageing. Other parameters, such as the ability to absorb water, saturation time and the glass transition temperature were also studied as a function of the different ageing conditions. The experimental results of the cyclic ageing studies showed that the water diffusion process changes with ageing cycles. It was also found that the glass transition temperature decreases with ageing cycles. Numerical analysis was also conducted using Fick’s law constants. Good agreement between the experimental and numerical results was obtained.

摘要

在现实世界的应用中，胶接接头经常暴露在环境中，并且会经历引起的循环老化条件。然而，循环老化下的粘合剂响应仍然相对未知。在这项研究中，通过进行单循环和循环老化实验，研究了环氧基粘合剂的湿热老化。本研究采用了不同的循环老化策略。在第一种策略中，老化时间设置为恒定值，而在第二种方法中，每个老化循环的最大吸收水含量受到限制。已经使用菲克定律分析了每个老化循环的吸收和解吸过程。这种分析可以确定扩散系数并评估它们如何受到循环老化的影响。其他参数，例如吸水能力，饱和时间和玻璃化转变温度也作为不同老化条件的函数进行了研究。循环老化研究的实验结果表明，水扩散过程随老化循环而变化。还发现玻璃化转变温度随着老化循环而降低。数值分析也使用菲克定律常数进行。在实验和数值结果之间获得了良好的一致性。