Nonlinear Dynamic Analysis of a Flexible Rod Fastening Rotor Bearing System
Nonlinear Dynamic Analysis of a Flexible Rod Fastening Rotor Bearing System
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DOI：
10.1115/gt2010-23368
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发表时间：
2010-10
期刊：
影响因子：
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通讯作者：
Heng Liu;Chen Li;Weimin Wang;Xiaobin Qi;Minqing Jing
中科院分区：
文献类型：
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作者：
Heng Liu;Chen Li;Weimin Wang;Xiaobin Qi;Minqing Jing
针对柔性连杆-紧固转子轴承系统，利用汉密尔顿原理建立了沿圆周沿着分布的连杆动力学模型，得到了n根连杆引起的附加刚度矩阵和附加广义弯矩的一般表达式.结果表明，当连杆数大于等于3且沿圆周沿着均匀分布时，由n根杆引起的附加刚度矩阵保持各向同性;同时，将轴作为一个整体结构，采用能够考虑轴向载荷影响的B-S单元进行建模，首先建立了FRRBS的动力学模型，然后采用能方便地考虑轴承非线性油膜力的分量模态综合法对模型进行了降阶，然后采用打靶法和路径跟踪技术得到了FRRBS的周期运动及其稳定裕度，用Floquet理论分析了周期运动的局部稳定性和分岔行为，结果表明，质量偏心和不平衡拉杆预紧力对系统的非线性稳定性和T周期运动的分岔有很大的影响，导致系统非线性动力学的溢出和T周期运动的稳定性和分岔的退化。
For flexible rod-fastening rotor bearing system (FRRBS),a dynamic model of tie rods distributed along the circumference is built by using Hamilton principle,and the general expressions of the additional stiffness matrix and additional generalized moment caused by n rods are obtained.The result shows that if the number of rods is greater than or equal to 3 and they are distributed uniformly along the circumference,the additional stiffness matrix caused by n rods keeps isotropy;and the unbalanced pre-tightening force of n rods leads to a constant generalized added-moment rotating at working speed.At the same time,the shaft is considered as an integral structure and is modeled by using Timoshenko beam-shaft element which can take the effects of axial load into consideration,so the whole dynamic model of FRRBS is obtained.Then the model is reduced by a component mode synthesis method,which can conveniently account for nonlinear oil film forces of the bearing.Afterward,the periodic motions and their stability margin are obtained by using shooting method and path-following technique,and the local stability and bifurcation behaviors of periodic motions are obtained by Floquet theory.The results indicate that mass eccentricity and unbalanced pre-tightening forces of tie rods have great influence on nonlinear stability and bifurcation of the T periodic motion of system,cause the spillover of system nonlinear dynamics and degradation of stability and bifurcation of T periodic motion.