The stability of the fixed pints of a flexible rotor supported by journal bearings is investigated through the Bifurcation diagrams. In this paper the effect of nonlinear electromagnetic harmonic force is added to the simultaneous consideration of the effects of the nonlinearity in curvature and inertia, mass eccentricity and hydrodynamic forces of the journal bearings. Solution of the Reynolds equation renders the pressure distribution in the bearings. The bearing forces are found from integrating the pressure distribution on the surface of bearings. Derivation of the equations is performed using the Hamilton's principle and the nonlinearity terms are related to the eccentricity and the curvature of shaft. Primary and combination resonances are imposed to the rotor-bearing system and steady state responses show the effects of magnetic and bearing forces on the stability of amplitudes. In combination resonance, frequency of the electromagnetic load is tuned as the average of the forward and backward natural frequencies of the rotor. Existence of unstable Hopf points demonstrates that periodic, quasi-periodic and chaotic motions may be arisen in the nonlinear behavior of rotor.

通过分叉图研究了由轴颈轴承支撑的挠性转子的固定销的稳定性。在本文中，将非线性电磁谐波力的影响添加到同时考虑轴颈轴承的曲率和惯性，质量偏心率和流体动力的非线性影响中。雷诺方程的解表示轴承中的压力分布。通过对轴承表面上的压力分布进行积分可以发现轴承力。方程的推导使用汉密尔顿原理进行，非线性项与轴的偏心率和曲率有关。初级共振和组合共振被施加到转子轴承系统，稳态响应显示出磁力和轴承力对振幅稳定性的影响。在组合共振中，将电磁负载的频率调整为转子前向和后向固有频率的平均值。不稳定的Hopf点的存在表明，转子的非线性行为中可能会出现周期性，准周期性和混沌运动。