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讨论了油膜轴承瞬态非线性油膜力的力学模型、数学表达式及其基本性质.指出建模中考虑油膜自由边界瞬态性的重要性;对短轴承论证了“动态π油膜”模型;对有限长轴承,提出了用变分法决定油膜瞬态自由边界位置;提出了非线性油膜力一般表达式,它由3个函数组成“瞬态刚度矩阵”和“瞬态阻尼矩阵”;导出了这3个函数的一般表达式;证明了瞬态阻尼矩阵的正定对称性,表明非线性油膜力具有正阻尼特性.具体讨论了两类油膜轴承的油膜力解案.一是圆柱短轴承油膜力精确解;二是采用变分方法对有限长椭圆轴承获得油膜力的高精度近似公式.通过实例,证实了变分方法的高效性.
The mechanical model, mathematical expression and basic properties of oil film bearing transient nonlinear oil film force are discussed. The importance of considering the transient boundary of oil film free boundary is pointed out. The model of “dynamic oil film” is demonstrated for short bearing. Finite element bearing is proposed, the method of variational method is proposed to determine the transient free boundary position of oil film. A general expression of nonlinear oil film force is proposed. It consists of three functions “transient stiffness matrix” and “transient damping matrix” The general expressions of these three functions are proved.The positive symmetry of the transient damping matrix is proved, which indicates that the nonlinear oil film force has a positive damping characteristic.The oil film force solutions of two kinds of oil film bearings are discussed in detail.The first is the short cylinder oil film force Accurate solution and the second is to use the variational method to obtain the approximate formula of the oil film force for the finite length elliptical bearing.According to the example, the high efficiency of the variational method is verified.