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为探讨层合板单钉接头在实际工作中多级疲劳破坏规律,首先通过特征尺寸为层合板端距与螺栓孔孔径之比为3、层合板宽度与螺栓孔孔径之比为3的层合板单钉接头准静态拉伸试验及常幅拉-拉疲劳试验,分析了层合板单钉接头实际损伤失效形式及单级疲劳破坏规律,为其多级疲劳试验各级应力水平的选取提供基础依据.然后对层合板单钉接头在载荷由高到低及由低到高2种加载方式2级载荷作用下的疲劳性能进行了试验研究,并使用经典线性累积损伤理论Miner法则分析计算了接头疲劳损伤值.结果表明:当应力水平由低向高施加时,疲劳损伤值大于1,而应力水平由高向低施加时,疲劳损伤值小于1.
In order to investigate the rule of multi-level fatigue failure of single nails in practice, firstly, the lamella sheet with the feature size of 3 and the ratio of the width of the lamination plate to the diameter of the bolt hole is 3, The quasi-static tensile test of nail joint and the normal tension-pull fatigue test were carried out. The actual damage failure modes and single-stage fatigue failure rules of single-nailed composite joints were analyzed, providing the basis for the selection of stress levels at different levels of multi-level fatigue test. Then the fatigue behavior of single nails on Laminates under two loadings with high load and low load and low load were studied. The fatigue damage of joints was analyzed by Miner’s rule of classical linear cumulative damage theory The results show that when the stress level is increased from low to high, the fatigue damage value is greater than 1, while the fatigue damage value is less than 1 when the stress level is applied from high to low.