随机振动疲劳寿命估算与试验验证

Random Vibration Fatigue Life Estimation and Test Verification

为了验证应用随机振动疲劳分析技术进行寿命预测的准确性,文章以汽车电喇叭支架为研究对象,首先进行模态测试校验有限元模型的准确性,然后通过扫频试验获取支架上某点的加速度曲线,再基于Isight软件确定结构阻尼的大小。通过进行电喇叭支架的随机振动疲劳仿真分析及试验,得出预测寿命为 338 min, 试验寿命在50~320 min之间。考虑到材料工艺、表面质量和存活率对疲劳寿命的影响,最终预测寿命为48 min。结果表明:由于结构受材料工艺和表面质量等因素的影响,疲劳寿命分布存在一定的离散性。但是,综合考虑各种不利因素的影响,可以准确预测疲劳寿命的下限值,有效地指导结构设计。

In order to verify the accuracy of life prediction using random vibration fatigue analysis techniques, the car electric horn bracket is taken as the research object, the accuracy of the modal test and finite element model is first carried out. The acceleration curve at a point on the support is then obtained by a sweep test, and the structural damping is determined based on Isight. Finally, the random vibration fatigue simulation analysis and test of the electric horn bracket are carried out. The predicted life is 338 min and the test life is between 50 to 320 min. Considering the influence of material process, surface quality and survival rate on fatigue life, the final predicted life is 48 min. The results show that the fatigue life distribution is discrete due to the randomness of material process and surface quality. However, considering the influence of various unfavorable factors, the lower limit of fatigue life can be accurately predicted, and the structural design can be effectively guided.