Abstract: As one of the important components of automobile parts, the lower cross arm of automobile suspension has an important impact on the safety of automobile. In order to ensure the development quality of automobile suspension lower cross arm products, this paper not only analyzes its fatigue life and sensitivity, but also determines the key influencing parameters of automobile lower cross arm fatigue life through comparative analysis, namely, material tensile strength, bushing stiffness, load amplification factor and surface roughness.The proportion and influence degree of each parameter in the fatigue life and sensitivity of the lower cross arm of the vehicle suspension are obtained by orthogonal experiment and variance test. It is found that among many parameters, the load amplification factor has the most prominent effect on the life of the lower cross arm of the vehicle. Therefore, in the design of the lower cross arm of the actual vehicle suspension, the load amplification factor can be regarded as the key object for reasonable and scientific control to avoid or reduce its impact on the design of the lower cross arm of the vehicle suspension.

Key words: Lower cross arm of suspension; Fatigue life; Sensitivity analysis; Orthogonal experiment

摘要： 汽车悬架下横臂作为汽车零部件中的重要组成部分之一，其质量优劣对汽车的安全性 具有重要影响。为确保汽车悬架下横臂产品开发质量，文章不但对其疲劳寿命及其敏感性进 行了分析，而且还通过对比分析法确定了汽车下横臂疲劳寿命关键的影响参量，即材料抗拉 强度、衬套刚度、荷载放大系数、表面粗糙度这四个参量。利用正交实验与方差法测试得到 了各参量在汽车下横臂疲劳寿命与敏感性中的占比情况与影响程度，发现在众多参量中，荷 载放大系数对汽车下横臂寿命的影响效果最为突出。因此，在实际汽车悬架下横臂的设计中 可将荷载放大系数视为重点关注对象，进行合理科学控制，避免或减少其对汽车悬架下横臂 设计的影响。

关键词: 悬架下横臂；疲劳寿命；敏感性分析；正交试验