Abstract: In order to study the influences of shock absorber damping coefficients on fatigue life of steering knuckles, taking a compact SUV(sport utility vehicle) as the research object, through modal analysis and testing of steering knuckles, the flexible body models and the fatigue simulation analysis models of steering knuckle were established. The rigid-flexible coupling multi-body dynamics models of the whole vehicle were established based on the parameters of the real vehicles, and based on the six-component forces of the wheel center and the strain signals of the steering knuckle monitoring points collected by the real vehicles in the testing proving ground, using virtual iteration method simulation the load time history(modal displacement) of steering knuckles was obtained. The fatigue life of steering knuckles in different shock absorber damping coefficients was analyzed by using modal stress recovery method, and the relationship between both of them was discussed. The results show that the fatigue life of steering knuckles increases first and then decreases with the increase of damping coefficients in the range considering both of comfort and safety of the whole vehicle, that is, the damage areas of the main area affecting the fatigue life of steering knuckles decreases first and then increases. The damage areas of the secondary area which affects the fatigue life of steering knuckles always increases with the increase of damping coefficients.

Key words: steering knuckle, shock absorber damping coefficient, virtual iteration, fatigue life, modal stress recovery

摘要： 为探明减振器阻尼系数对转向节疲劳寿命的影响规律，以某紧凑型SUV为研究对象，通过对转向节模态分析与测试，建立其柔性体模型与疲劳仿真分析模型；以实车参数建立了整车刚柔耦合多体动力学模型，并以试验场强化路实车采集的轮心六分力和转向节监测点应变信号为基础，应用虚拟迭代法仿真获取了转向节载荷时间历程(模态位移)；应用模态应力恢复法运算分析了减振器在不同阻尼系数条件下转向节的疲劳寿命，探讨了二者的相互关系。研究表明，在兼顾整车舒适性与安全性的阻尼系数范围内，随减振器阻尼系数增大，转向节疲劳寿命先增后减，即影响其疲劳寿命的主要区域损伤面积先减后增，而影响转向节疲劳寿命的次要区域损伤面积始终随着减振器阻尼系数的增大而增大。

关键词: 转向节, 减振器阻尼系数, 虚拟迭代, 疲劳寿命, 模态应力恢复