为了研究波纹刚度特性以及其对箔片轴承动力学特性的影响,设计了波纹箔片刚度测试试验台。分别对两端固定和一端固定一端自由两种约束条件下的波纹箔片刚度进行了测试,并将试验结果与仿真结果进行了对比分析。最后基于轴承波纹结构刚度特性,利用小扰动法求解了轴承动力学特性系数,研究了波纹箔片刚度特性对轴承动力学特性系数的影响。结果表明:两端固定波纹箔片刚度较一端固定一端自由波纹箔片单位宽度刚度大5倍以上,并且随着波纹变形量的增加,两端固定约束使其波纹箔片刚度比一端固定一端自由波纹箔片更具有非线性,而刚度仿真结果并没有体现出非线性,只是模型中引入的结构摩擦因数使得刚度值随摩擦因数有所增大。最后轴承载荷增加会使得轴承刚度系数以及主阻尼增加,其他阻尼系数减小,并且鉴于波纹箔片刚度非线性的原因,采用刚度试验值计算得到的轴承动力学系数增加幅度要明显大于文献仿真模型。
In order to study the bump stiffness and its effect on dynamic coefficients of foil bearing, a test rig is designed to measure the stiffness of bump foil. Two type of bump foil under fixed-fixed ends and fixed-free ends constraint conditions are both tested and the experimental results are compared with numerical results. Finally, based on the obtained bump foil stiffness, the dynamic coefficients of foil beating are obtained by using perturbation method, and the effect of bump foil stiffness on these coefficients are studied. The results indicate that the fixed-fixed ends bump foil has 5 times greater stiffness per unit width than fixed-free ends bump foil, and with the increase of bump deflection, the stiffness of fixed-fixed ends bump foil is more nonlinear than the fixed-free ends bump foil, but the numerical results don't show any same nonlinear feature except of the increase of stiffness value due to the structural friction coefficient. At last, the bearing stiffness and direct damping can be enlarged with the increase of bearing load while the other damping values decrease, and values of bearing dynamic coefficients using tested bump stiffness grow faster than using numerical bump foil stiffness due to the nonlinear stiffness features of bump foil.