基于实测载荷谱的副车架疲劳寿命估算方法

Prediction Method on Subframe′s Fatigue Life Based on Measured Load Spectrum

为准确预测某副车架疲劳寿命,对其进行三维建模与有限元分析,获得其结构应力分布,并确定副车架的疲劳损伤热点;试验场条件下测取副车架的应变载荷,通过频谱分析与低通滤波等计算副车架结构各测点的最大主应力,利用雨流计数法编制副车架载荷谱;利用局部应力应变法与Miner准则进行应力集中修正,完成副车架的疲劳寿命预估。估算得出该副车架试验场预期寿命为9 120 h。

To predict accurately fatigue life of a subframe, we build a 3D model of this subframe and make FE analysis, and get structural stress distribution and determine fatigue damage heat points. We measure the strain load of the subframe in the proving ground, and use frequency spectrum analysis and low passing filtering to calculate the maximum principal stress of the subframe. We use rain flow count method to compile the load spectrum. Using local stress-strain method and Miner standard, we revise the stress concentration, and complete fatigue life prediction of subframe. The results show that estimation life of suhframe is 9210 hours.