线接触弹流润滑状态下极值应力的研究

发布时间：2018-09-01 06:03

【摘要】：齿轮、轴承等以点、线接触的零件在正常工作时往往处于弹性流体动力润滑状态,但是对于此类零件强度设计所依据的赫兹应力理论则完全忽略掉了润滑的影响,实际上,润滑对零件接触表面应力的分布及性能有着重要的影响,不但会在出油口附近产生二次压力峰,还会在二次压力峰下产生应力集中。因此,弹流润滑状态下压力极值的研究对此类零件的强度设计及疲劳寿命预测具有重要的意义。(1)给出了稳态线接触弹流润滑理论的数学模型及求解方程,详细介绍了Newton-Raphson法,编写了计算程序,通过具体算例验证了程序的正确性与可用性。(2)详细研究了弹流润滑状态下无量纲速度、载荷及材料参数对压力极值的影响,并采用多元回归分析法给出了二次压力峰值、中心压力及二次压力峰位置的拟合公式,对其进行了显著性检验及精度校核,结果表明,在较宽的参数范围内,该拟合公式完全满足工程设计的需要。(3)详细研究了弹流润滑状态下接触区次表面应力的分布。探究了最大剪应力与二次压力峰的关系及最大剪应力的位置关系,结果表明:随着二次压力峰幅值的增大,最大剪应力先减少后增大;最大剪应力深度随着载荷的增加逐渐加深,最终近似于赫兹接触状况下应力的分布,随着速度的增大而接近于接触区表面;并且给出了最大剪应力位置横坐标的拟合公式。
[Abstract]:The gear, bearing and other parts with point and line contact are often in the state of elastohydrodynamic lubrication in normal operation, but the Hertz stress theory, which is based on the strength design of this kind of parts, completely ignores the influence of lubrication, in fact, Lubrication has an important effect on the distribution and performance of contact surface stress, which not only produces a secondary pressure peak near the outlet, but also produces a stress concentration under the secondary pressure peak. Therefore, the study of pressure extremum under elastohydrodynamic lubrication is of great significance to the strength design and fatigue life prediction of this kind of parts. (1) the mathematical model and solution equation of the steady-state linear contact elastohydrodynamic lubrication theory are given, and the Newton-Raphson method is introduced in detail. The correctness and availability of the program are verified by an example. (2) the effects of dimensionless velocity, load and material parameters on the pressure extremum under elastohydrodynamic lubrication are studied in detail. The fitting formulas of the peak value of secondary pressure, central pressure and the position of the peak of secondary pressure are given by using the method of multiple regression analysis. The significance and accuracy of the formula are verified. The results show that in a wide range of parameters, The fitting formula fully meets the needs of engineering design. (3) the distribution of subsurface stress in contact area under elastohydrodynamic lubrication is studied in detail. The relationship between the maximum shear stress and the secondary pressure peak and the position of the maximum shear stress are discussed. The results show that the maximum shear stress decreases first and then increases with the increase of the amplitude of the second pressure peak. The maximum shear stress depth gradually deepens with the increase of load, and finally approximates to the stress distribution under Hertz contact condition, and approaches to the contact area surface with the increase of velocity, and the fitting formula of the maximum shear stress position is given.
【学位授予单位】：郑州大学
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TH117.2

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