Abstract

The evolution of dissipation energy of the uniaxial and multiaxial fatigue experiments on the automobile sealant adhesively bonded butt joints was investigated by the method of fatigue dissipation energy analysis and fatigue failure identification. The results demonstrated that the dissipation energy increased and the fatigue life decreased with the increase of stress amplitude, mean stress, and the decrease of cycle time. Meanwhile, the non-proportional loading path resulted in greater dissipation energy and shorter fatigue life than that of uniaxial and proportional loading path. Moreover, the existing energy-based model using the energy dissipated in different cyclic loading stages as the fatigue parameters were adopted to predict the fatigue life of the automobile sealant adhesively bonded butt joints, respectively. The practical limitations of the prediction model using the total dissipation energy as the fatigue parameter were evaluated. Therefore, a novel energy-based fatigue life prediction model was proposed which using the partial steady stage of dissipation energy curves as the parameters. The predicted results of the novel model and the comparison with that of the existing energy-based model indicated that the novel model had an excellent ability to predict the fatigue life, and was more practical in engineering application for the automobile sealant adhesively bonded butt joints.

摘要

采用疲劳耗散能分析和疲劳失效识别方法，研究了汽车密封胶粘接对接接头单轴和多轴疲劳实验耗散能的演变规律。结果表明，随着应力幅值、平均应力的增加和循环时间的减少，耗散能增加，疲劳寿命降低。同时，非比例加载路径比单轴和比例加载路径导致更大的耗散能量和更短的疲劳寿命。此外，采用现有的基于能量的模型，以不同循环加载阶段的能量耗散为疲劳参数，分别预测汽车密封胶粘接对接接头的疲劳寿命。评估了使用总耗散能量作为疲劳参数的预测模型的实际局限性。为此，提出了一种以耗散能曲线的局部稳态阶段为参数的基于能量的疲劳寿命预测模型。新模型的预测结果以及与现有基于能量的模型的比较表明，新模型具有良好的疲劳寿命预测能力，在汽车密封胶粘接对接接头的工程应用中更具有实际意义。