考虑焊接质量的铝合金车体关切焊缝的疲劳寿命预测

Fatigue Life Prediction Considering Welding Quality for Concerned Welds of Aluminum Alloy Vehicle Body

利用裂纹扩展分析方法和质量分类法研究铝合金车体含缺欠焊接结构的疲劳寿命问题。首先,研究IIW:2015的基于Paris定律的裂纹扩展分析的理论基础和BS 7910:2019的基于考虑焊接缺欠质量的S-N曲线的质量分类法的算法原理;其次,归纳总结了这2种方法进行考虑焊接质量的焊接结构疲劳寿命评估流程;再次,在疲劳载荷作用下,基于BS EN 1999-1-3:2007的名义应力法对某动车组铝合金车体进行疲劳分析,确定车体疲劳关切焊缝部位;最后,分别利用裂纹扩展分析方法和质量分类法对车体关切焊缝侧门下角进行考虑初始裂纹的疲劳寿命评估。结果表明:基于质量分类法的剩余寿命为1.4×106次,基于裂纹扩展分析法的剩余寿命为2.64×106次。

The crack propagation analysis method and quality classification method are used to study fatigue life problem of welded structure with defects in aluminum alloy vehicle body.First,the theoretical basis of crack propagation analysis is studied based on Paris law in IIW:2015 and the algorithm principle of quality classification method based on S-N curve considering welding defect quality in BS 7910:2019.Then,these two methods are summarized for the fatigue life assessment process of welded structure considering welding quality.Next,the fatigue analysis of aluminum alloy vehicle body of an EMU was carried out under the action of fatigue load based on the nominal stress method of BS EN 1999-1-3:2007,and the weld position of fatigue concern of vehicle body is determined.Finally,the fatigue life assessment considering initial crack for concerned weld of side door lower corner of vehicle body is carried out by using crack propagation analysis method and quality classification method respectively.The results show that the residual life based on quality classification method is 1.4x10°cycles,and the residual life based on crack propagation analysis method is 2.64x 10°cycles.