In real applications, adhesive joints are commonly subjected to fatigue and mixed mode loading conditions. The aim of the current work is to experimentally analyse the influence of mode mixity on the fatigue strength of joints with an epoxy‐based adhesive. Different adhesive systems (acrylic and epoxies) were considered for pure mode I fatigue loading conditions. To achieve this, Arcan joints with an epoxy adhesive were manufactured and tested at different mode mixities. Based on stiffness degradation, monitored during the tests, damage evolution was calculated for different loading conditions and for all the tested adhesives. Finally, fatigue envelopes were constructed for different fatigue life regimes. Results show that a shear loading component reduces both the static strength and fatigue life of the joints. A small reduction rate of the stiffness was found throughout the most part of the life until a sudden drop was observed, indicating a smooth damage evolution.

中文翻译：

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模式混合和胶粘剂体系对胶粘剂接头疲劳寿命的影响

在实际应用中，胶粘接头通常会承受疲劳和混合模式的载荷条件。当前工作的目的是通过实验分析模式混合对基于环氧树脂的粘合剂的接头疲劳强度的影响。对于纯模式I疲劳载荷条件，考虑使用不同的粘合剂体系（丙烯酸和环氧树脂）。为此，制造了具有环氧粘合剂的Arcan接头，并在不同模式下的混合比下对其进行了测试。根据在测试过程中进行监测的刚度退化，计算出不同载荷条件和所有测试粘合剂的损伤演变。最后，针对不同的疲劳寿命方案构造了疲劳包络线。结果表明，剪切载荷分量会降低接头的静态强度和疲劳寿命。