The fatigue life of a steering knuckle was predicted using finite element method, multi-body dynamics and stress field intensity approach. Six-component forces of all steering knuckle joints were obtained in time history by multi-body suspension system dynamic simulation. Then the most easily fatigue damage region was confirmed. The stress fields were then calculated at each step and the numbers of each stress field value were counted by rain flow method. The fatigue life was then calculated by stress field intensity approach. The results show that the connected region between wishbone and rib is the most easily damaged region and the fatigue life is 2.4×107 time.

利用多体动力学理论建立了双横臂悬架系统的刚柔耦合动力学模型,采用国家B级路面谱进行模拟激励,得到了汽车转向节的六分力时间历程。结合转向节有限元模型,获得了转向节实时等效单元应力,通过统计确定了最易疲劳的损伤区域。运用应力场强理论来计算应力场强,并使用雨流计数法进行了统计,综合计算了转向节的疲劳寿命。结果显示,连接车轮横臂处最易发生疲劳破坏,特定条件下的疲劳循环寿命为2.4×107次。

转向节, 应力场强法, 随机激励, 损伤区域, 疲劳寿命