基于频率响应分析的越野车车架疲劳寿命预估

Fatigue Life Prediction of SUV Frame Based on Frequency Response Analysis

以某越野车车架为研究对象,对车架有限元模型在MSC.Nastran中进行频率响应分析,以获得输入和结构应力之间的传递函数;以车架为柔性体在ADAMS中建立整车刚柔耦合动力学模型,得到相应的载荷时间历程;综合有限元分析获得的频率响应结果和由以上随机载荷时间历程数据所转换得到的功率谱密度,进行基于频域的车架疲劳寿命预估,分析结果与实际道路试验情况相符,证明该分析方法可以在产品设计阶段准确、高效地预估车体结构疲劳寿命.

Taking a SUV frame as a research object, by means of frequency response analysis with software MSC Nastrain, the transfer functions between input and structural stress are obtained in the frame finite element model. A rigid-flexible coupling vehicle model with flexible frame components was built, and the loading time histories are calculated at the same time. The frame fatigue life was predicted in Frequency Domain according to the results of frequency response analysis and the Power Spectral Density transformed from the loading time histories. Comparing with the road test results, the simulation showed that the above analytical method was proven effective in evaluating the fatigue life of car-body structure at product design stage.