This study numerically analyzes and investigates the effects of the bearing design parameters of a tilting pad journal bearing (TPJB) on the pad-pivot friction-induced nonlinear rotordynamic phenomena and bifurcations. The bearing parameters were set to the pad preload, pivot offset, spherical pivot radius, and bearing length to diameter (L/D) ratio. The Stribeck curve model (SCM) model was applied at the contact surface between the pad and the pivot, which varied to the boundary-mixed-fluid friction state depending on the friction condition. The rotor-bearing model was set up with a symmetrical five-pad TPJB system supporting a Jeffcott type rigid rotor. The fluid repelling force generated in the oil film between each pad and the shaft was calculated using a finite element method. The simulation recurrently conducted the transient numerical integration to obtain the Poincaré maps and phase states of the journal and pad with various bearing design variables, then the nonlinear properties of each condition were analyzed by expressing the bifurcation diagrams. As a result, the original findings of this study are: (1) The pad preload and pivot offset significantly influenced the emergence of Hopf bifurcations and the associated limit cycles. In contrast, (2) the pivot radius and L/D ratio contributed relatively less to the friction-induced instability. Resultantly, (3) all the effects diminished when the rotor operated under the larger mass eccentricity of the disc.

中文翻译：

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倾斜垫轴颈轴承设计参数对垫-轴摩擦和非线性转子动力分叉的影响

本研究通过数值分析和研究了可倾瓦块轴颈轴承（TPJB）的轴承设计参数对瓦块-枢轴摩擦引起的非线性转子动力学现象和分叉的影响。轴承参数设置为轴瓦预载，枢轴偏移，球形枢轴半径和轴承长度与直径（L / D）的比率。斯特里贝克曲线模型（SCM）模型应用于轴瓦和枢轴之间的接触表面，随摩擦条件的变化而变化为边界混合流体的摩擦状态。转子轴承模型由对称的五垫板TPJB系统建立，该系统支持Jeffcott型刚性转子。使用有限元方法计算在每个衬套和轴之间的油膜中产生的流体排斥力。该模拟反复进行瞬态数值积分，以得到庞加莱图和带有各种轴承设计变量的轴颈和轴瓦的相态，然后通过分叉图分析每种条件的非线性特性。结果，该研究的原始发现是：（1）垫块的预紧力和枢轴偏移量显着影响Hopf分叉的出现和相关的极限环。相反，（2）枢轴半径和L / D比对摩擦引起的不稳定性的贡献相对较小。结果，（3）当转子在较大的圆盘质量偏心率下运行时，所有影响都会减弱。然后通过表达分叉图来分析每种条件的非线性性质。结果，该研究的原始发现是：（1）垫板的预紧力和枢轴偏移量显着影响Hopf分叉的出现和相关的极限环。相反，（2）枢轴半径和L / D比对摩擦引起的不稳定性的贡献相对较小。结果，（3）当转子在较大的圆盘质量偏心率下运行时，所有影响都会减弱。然后通过表达分叉图来分析每种条件的非线性性质。结果，该研究的原始发现是：（1）垫板的预紧力和枢轴偏移量显着影响Hopf分叉的出现和相关的极限环。相反，（2）枢轴半径和L / D比对摩擦引起的不稳定性的贡献相对较小。结果，（3）当转子在较大的圆盘质量偏心率下运行时，所有影响都会减弱。（2）枢转半径和L / D比对摩擦引起的不稳定性的贡献相对较小。结果，（3）当转子在较大的圆盘质量偏心率下运行时，所有影响都会减弱。（2）枢转半径和L / D比对摩擦引起的不稳定性的贡献相对较小。结果，（3）当转子在较大的圆盘质量偏心率下运行时，所有影响都会减弱。