基于等效结构应力法的ST12点焊疲劳寿命分析

摘要

The constant load fatigue test of ST12 low carbon steel tensile shear test specimen under different load conditions is carried out. Based on the structural stress method under ASME standard in USA, the grid insensitive characteristics of ST12 spot welding model are verified. The prediction equation of the structural stress calculated by the different load conditions and the corresponding experimental fatigue life is analyzed by the least squares method. The predicted life of the predicted life is compared with the predicted life of the main S-N curve method. The results show that the prediction life of the main S-N curve method is dangerous and the prediction equation based on the structural stress method is suitable for the ST12 low carbon steel tensile shear test specimen under the high load fatigue condition.%对ST12低碳钢拉剪点焊试件进行不同载荷工况下恒幅疲劳加载试验.使用基于美国ASME标准下的结构应力法对ST12点焊模型验证网格不敏感特性.利用最小二乘法将不同载荷条件下计算的结构应力与相应试验疲劳寿命拟合出预测方程,利用预测方程估算出的预测寿命与主S-N曲线法的预测寿命对比分析.研究表明:对于ST12低碳钢拉剪点焊试件,在低载高周疲劳工况下,主S-N曲线法的预测寿命偏危险,基于结构应力法的预测方程较为适用.