转子系统盘轴松动故障动力学建模和仿真研究

Research on Dynamic Modeling and Simulation of Rotors with Loose Disc

现有的松动故障动力学特性研究主要集中在非转动部件的配合松动上,而转动部件松动故障却忽略了。针对此不足,采用Hertz接触理论,建立了盘轴碰摩模型和盘轴松动转子系统的动力学模型,并进行了仿真研究。讨论了转轴转速、盘轴弹性模量、盘轴间隙、转轴阻尼、转盘阻尼、转动阻尼、转盘初始转速对转盘运动状态的影响以及转盘振动特性、盘轴位移差的变化和盘轴运动轨迹。结果表明:转轴转速、盘轴弹性模量、盘轴间隙、转轴阻尼、转盘阻尼、转动阻尼、转盘初始转速对转盘运动状态有明显的影响;在某些转速下,拍振现象会出现在转轴的波形中,其原因可能是由盘轴碰摩或者盘轴碰撞所导致,在频谱图中会出现二倍频、三倍频等高次谐波成分,随盘轴转速差的增大,高倍频的频率也会增多;当转盘转速趋于平稳时,盘轴位移差也会趋于平稳;锯齿现象会出现在转轴转盘运动轨迹中,盘轴摩擦力方向的改变会造成锯齿方向不确定,且转盘的锯齿现象表现更加明显。研究成果对盘轴松动故障的动力学特性研究具有重要的参考价值。

The traditional research on the dynamic characteristics of rotor system with loose fault mainly focus on the looseness of the non-rotating parts. However, the loose fault of the rotating parts is neglected. Based on this deficiency, a rotor-disc rubbing model is established by Hertzian impact-contact theory, and the motion equation of rotor system with loose disc is also established. The fourth-order Runge-Kutta method is used to solve this equation. The influence factors of the disc motion state, disc vibration characteristics, variation of displacement between loose disc and shaft, and trajectory of shaft and disc are discussed. The research results show that some factors, such as the shaft speed, elasticity modulus of shaft and disc, clearance between loose disc and shaft, shaft damping, disc damping, rotational damping, and initial speed of loose disc have a major effect on the motion state of loose disc. The waveform of the rotating shaft may have the phenomenon of beat vibration at certain rotating speed, this phenomenon may be caused by the loose disc and shaft’s vibration or collision. Some high frequency multiplication occurs in the spectrum, and the multiplication of high frequency increases with the increases of disc and shaft’s speed difference. The displacement between loose disc and shaft tends to be stable as the turntable speed tends to be stable. The sawtooth phenomenon occurs in the trajectory diagram of the loose disc and shaft. The change of the frictional force of the disc-shaft leads to the inconsistency of the saw tooth direction, and the sawtooth phenomena of disc is more obvious. The research results have an important reference value for the research of dynamic characteristics of rotor system with loose disc.