基于台架试验数据的铸件疲劳寿命分析与应用

Fatigue Life Analysis and Application Based on Bench Test Data of Casting Rear Axle

以商用车铸造后桥壳为研究对象,对多个类型桥壳台架试验疲劳寿命进行数据分析处理,得到失效时的加载循环次数。应用基于时间历程载荷的有限元疲劳分析方法,得到铸造桥壳在对应载荷循环下的疲劳等效应力,联合疲劳等效应力与失效次数获得铸造桥壳的S-N曲线。结果表明,当前分析的铸造桥壳存在缺陷控制水平低的问题,需要提升制造工艺水平,并提出在设计中制定缺陷等级分类的重要性。应用有限元疲劳分析联合试验数据,可以在工艺水平稳定的前提下,提前有效预测新设计结构的疲劳寿命,将有限元分析结果与制造工艺联系起来,扩展了试验数据的实用性。

Taking the cast iron rear axle housing of commercial vehicle as the research object,the bench test fatigue life data analysis and processing of several axle shell types are carried out.And the number of loading cycles at failure is obtained.Using the finite element fatigue analysis method based on time history load,the fatigue equivalent stress of the cast axle housing under the corresponding load cycle is obtained.Then the S-N curve of the cast axle housing is fitted by combining the fatigue equivalent stress and number of failure cycles.The results show that,the current analysing cast axle housing has a problem of low defect control level.The manufacturing process level needs to be improved.Moreover,the importance of formulating defect level classification during design is proposed.The application of the finite element fatigue analysis combined with the test data can effectively predict the fatigue life of the newly designed structure on the premise of stable process level.The finite element analysis results and manufacturing process can be combined effectively to expand the practicability of the bench test data.