随机不确定性下Kriging辅助的谐波减速器柔轮疲劳寿命预测

Kriging-assisted fatigue life prediction of harmonic reducer flexible wheel under random uncertainty

柔轮作为谐波减速器核心传动件,在循环交变载荷作用下容易发生疲劳失效,其疲劳寿命直接影响谐波减速器的工作寿命。为揭示随机不确定性因素对谐波减速器柔轮疲劳寿命的影响规律,本文考虑材料属性和载荷等不确定因素对谐波减速器柔轮开展疲劳寿命预测研究,以期实现更客观地评估柔轮疲劳寿命。首先,建立柔轮的三维模型和有限元模型,通过有限元分析及寿命计算获得确定性条件下的柔轮寿命。然后,将材料属性及载荷考虑为随机变量,采用拉丁超立方抽样方法对柔轮进行试验设计。最后,基于主动学习Kriging模型和柔轮材料P-S-N曲线,通过逐一加点的方式对柔轮进行疲劳寿命分析,获得疲劳寿命统计结果,并与确定性条件下的柔轮疲劳寿命结果进行对比。结果表明,随机不确定因素影响下柔轮疲劳寿命预测结果与确定性条件下相比有所降低,对柔轮抗疲劳设计具有一定指导意义。

As the core transmission of a harmonic reducer,the flexible wheel is prone to failure under cyclic loads,whose fatigue life can directly affect the life of the entire harmonic reducer.To reveal the influence of random uncertainties on the life of the flexible wheel,this study explores its fatigue life prediction by accounting for the uncertainties arising from material properties and loads.Firstly,the three-dimensional model and the finite element model of flexible wheel are established,and the fatigue life of flexible wheel under deterministic conditions is computed using finite element analysis and life prediction strategy.Subsequently,uncertainties are designated according to the material properties and loads,and the Latin hypercube sampling technique is employed to experimentally design the flexible wheel.Finally,according to the active learning Kriging model and P -S -N curve of the flexible wheel material,the fatigue life analysis is performed by sequentially adding points.Comparisons are conducted between the statistical and deterministic results of the fatigue life of the flexible wheel.Results indicate that the fatigue life considering random uncertainties is shorter compared with the one under deterministic conditions,which offers a reference for the fatigue resistance design of flexible wheels.