考虑硬度分布的镁合金搅拌摩擦焊搭接接头疲劳寿命预测

Fatigue Life Prediction of Friction Stir Welded Lap Joint of Magnesium Alloy Considering Hardness Distribution

为了研究含有hook缺陷的镁合金搅拌摩擦焊搭接接头的硬度分布对其疲劳寿命的影响,建立了含有同一hook缺陷的两个有限元模型,一种考虑硬度分布,另一种不考虑硬度分布,分别对模型赋予材料属性。利用Abaqus有限元软件进行拉伸模拟试验,分析接头在不同载荷下的应力应变,并利用两种疲劳损伤方程进行了寿命预测。结果表明,在hook尖端周围出现严重的应力集中现象。采用SWT疲劳损伤方程进行疲劳寿命预测更加准确,其误差在2倍之内。当考虑搭接接头硬度分布时,寿命预测更加准确。

In order to study the influence of hardness distribution on the fatigue life of magnesium alloy friction stir lap welded joint with hook defect, two finite element models with the same hook defect were established. One considered the hardness distribution and the other did not consider the hardness distribution, and the properties were attributed to the models respectively. The tensile test was simulated by using the finite element software Abaqus, the stress and strain of the joint under different loads were analyzed, and the fatigue life was predicted by using the two fatigue damage equations. The results show that there is severe stress concentration around the hook tip. It is more accurate to predict the fatigue life with SWT fatigue damage equation, and the error is within 2 times. When the hardness distribution of lap joint is cosidered, the life prediction is more accurate.