某轿车前副车架服役载荷模拟试验加速方法研究*

服役载荷模拟试验能准确地预测零部件的疲劳寿命。为节省试验时间，急需开发出一套合理、实用的加速试验方法。重点研究在不具备结构局部应变响应，仅具备外部激励载荷如力、位移、和加速度等情况下的试验加速方法。基于修正Miner准则，以伪损伤保留比例作为小载荷删除准则，并结合疲劳数据编辑(Fatigue data editing， FDE)技术，提出一套便于工程应用的服役载荷模拟试验加速方法。以某轿车前副车架的疲劳试验为例，分别编制伪损伤保留比例为99%、95%和90%的加速谱。综合考虑各加速谱的载荷特征和加速效果，选用95%加速谱、90%加速谱和原始谱分别建立台架试验。试验结果表明两种加速谱在有效节省试验时间的同时，均获得了与原始谱相同的试验结果，且90%加速谱的加速试验效果更为显著。本方法便于工程应用，可为其他汽车零部件的服役载荷模拟试验提供参考。

Research on Accelerated Testing Method for the Service-simulation Fatigue Test of Automotive Front Sub-frame

The component fatigue life can be precisely predicted by service-simulation fatigue test.A set of reasonable and practical accelerated testing method is eagerly required to save test time.The emphasis of this research is on the accelerated testing method for the condition that only outer excitations such as force,displacement and acceleration are possessed while local strain responses are not possessed.A set of engineering-application-conveniently accelerated testing method is created for the service-simulation fatigue test.This approach is achieved by applying the modified Miner rule,the fatigue data editing(FDE) technique and treating the pseudo damage retention rate as the small load omission threshold.Taking automotive front sub-frame fatigue tests as an example,three accelerated loading spectra with pseudo damage retention rate of 99％,95％ and 90％ are generated.The 95％ and 90％ retention accelerated spectra and the original spectrum are selected to conduct the fatigue tests by fully considering the load characteristics and acceleration effects of every accelerated loading spectrum.Test results show that both the two accelerated spectra have reduced test time efficiently while guaranteed the same test results as those of original spectrum tests.Additionally,the 90％ retention accelerated spectrum is proved to have better acceleration effect.This set of method is engineering-application-conveniently and is an alternative way for other automotive components service-simulation fatigue tests.