摘要
针对周向拉杆转子轴承系统,将拉杆简化为无质量、受预紧的线性弹簧,得到周向拉杆提供的附加刚度矩阵和附加广义力矩;对具有粗糙表面的长方微元体进行有限元接触分析,得到不同载荷作用下的法向和切向界面接触刚度;计入界面接触刚度和周向预紧拉杆的影响,采用受轴向载荷的Timoshenko梁轴有限单元建立周向拉杆转子轴承系统的非线性动力学模型。基于系统的局部非线性特性进行自由度缩减后,运用结合预估—校正机理的Poincaré-Newton-Floquet方法对滑动轴承支承下周向拉杆转子系统的非线性动力特性进行研究,得到不同转速和质量偏心下系统稳态周期解的稳定性边界和分岔形式。结果表明,系统存在同步周期解、准周期解和倍周期解对应的参数区域,随着转速的增加,当质量偏心较小时,周期解发生准周期分岔,当质量偏心较大时,周期解发生倍周期分岔。考虑界面接触刚度后,系统的分岔失稳转速降低;预紧不均时,系统在更低的不平衡量下发生倍周期分岔。
For circumferential rod fastening rotor bearing system,the additional stiffness matrix and additional generalized moment provided by circumferential rods are obtained after simplifying the rod as massless,preloaded linear spring;the normal and tangential interface contact stiffness under different loads are obtained after finite element analysis on the cuboid contact model with rough surface;including the effects of interface contact stiffness and preloaded circumferential rods,the nonlinear dynamic model of circumferential rod fastening rotor bearing system is built using Timoshenko beam element subjected to axial force.After the system degrees of freedom are reduced based on local nonlinearity property,the nonlinear dynamic characteristics of circumferential rod fastening rotor supported by journal bearing are studied using Poincaré-Newton-Floquet method combined with prediction-correction technique,and the local stability and bifurcation behaviors of periodic motion with different speeds and mass eccentricities are obtained.The results show that the system has parameter regions corresponding to periodic motion,quasi-periodic motion and period-doubling motion.With the increase of speed,period-doubling bifurcation occurs with small eccentricity and quasi-periodic bifurcation occurs with large eccentricity.The threshold speed of system bifurcation decreases after considering interface contact stiffness,and period-doubling bifurcation occurs at lower mass eccentricity with unbalanced preload forces.
出处
《机械工程学报》
EI
CAS
CSCD
北大核心
2011年第23期82-91,共10页
Journal of Mechanical Engineering
基金
国家重点基础研究发展计划资助项目(973计划
2007CB707705
2007CB707706)
关键词
拉杆转子
接触刚度
非线性
分岔
稳定性
Rod fastening rotor Contact stiffness Nonlinear Bifurcation Stability
