前副车架焊缝疲劳分析和寿命优化

为评估前副车架的耐久性能,利用FEMFAT分析某汽车前副车架的疲劳寿命.提出焊缝不同区域单元的尺寸要求和焊缝连接单元的厚度要求,以保证前副车架焊缝的局部应力真实可信;采用S-N法预测焊缝疲劳寿命,计算得到的开裂位置和行驶距离与道路试验吻合良好;通过加强局部结构并重新布置焊缝位置,使前副车架通过耐久试验测试.分析表明:通过规范焊缝的建模要求,根据实际结构设置合适的焊缝类型,可准确预测焊缝的疲劳寿命,指导焊缝布置,优化产品结构.

Front sub-frame weld fatigue analysis and life optimization

To evaluate the durability of front sub frame, the fatigue life of the front sub-frame of an automobile is analyzed by FEMFAT. The requirements on element size around weld and thickness of weld connection elements are proposed to ensure the reliability of the local weld stress of the front sub frame; the weld fatigue life is predicted by S-N method, and the crack location and the automobile travel distance are well consistent with those obtained by road test; the local structure enhancement and weld re-layout are implemented to make the front sub-frame pass the durability test. The analysis indicates that, by specifying the requirements on weld modeling and choosing reasonable weld type according to the real structure, the weld fatigue life can be predicted accurately, which can guide the weld layout and optimize the product structure.