航空圆柱滚子轴承热力耦合下疲劳寿命研究

Fatigue Life Research for Aeronautic Rolling Bearing with Thermo-mechanical Coupling

以M50NiL航空圆柱滚子轴承为研究对象,基于Lundberg-Palmgren疲劳寿命理论和Hertz接触理论,结合Goodman公式及材料P-S-N曲线,综合考虑热应力和结构应力的共同作用,建立其疲劳寿命模型。该模型主要与最大Hertz接触应力及材料系数相关。在有限元软件ANSYS求解应力过程中,采用热塑性有限元法,计算温度场载荷;将摩擦热载荷产生的温度场和热应力分布做为应力分析的边界条件,推导轴承在热力耦合下的应力分布规律,并对某直升机单工况作用下的主减速器圆柱滚子轴承给出疲劳寿命评估,评估表明与试验值误差仅为11.61%。研究结果表明,该疲劳寿命模型综合考虑热应力和结构应力的影响,是一种安全、有效的疲劳寿命估算方法。

A fatigue life model of aeronautic rolling bearing made by M50NiL steel was established with Goodman for- mula and material P-S-N curves,based on Lundberg-Palmgren fatigue life theory （L-P theory） and Hertz contact theory, considered the effect of thermo-mechanieal coupling.The model was mostly related to the maximum Hertz contact stress and material coefficients.When solving the stress by the software of ANSY, the thermal load was calculated by using thermoplas- tic finite element method, and the regularities of loading distributions under the effect of thermo-mechanical coupling were determined by using the distribution of heat stress as boundary conditions of stress analysis.According to the data above, the fatigue life of the main reducer cylindrical roller bearing of a helicopter under one working condition was evaluated, and the error of the evaluation result was only 11.61% compared with the test value.The results show that the evaluation result cal- culated by this method is securer than the test result, which indicate that the method is a safe and effective evaluation method of fatigue life.