基于磁流变阻尼器的轴系扭振特性研究

针对传统被动硅油减振器调谐范围较窄、不易匹配的问题，基于磁流变液的流变效应，提出并设计了一种应用于轴系扭振半主动控制的磁流变阻尼.根据所设计的磁流变阻尼器结构，推导建立了其力学模型，并对其进行了磁场仿真；然后将其引入到曲轴系统中，建立磁流变阻尼器-曲轴系统耦合模型，利用Newmark法进行数值仿真，获得曲轴系统的扭振响应，并分析作用于磁流变阻尼器上的电流对扭振特性的影响.结果表明:磁流变液板极外的漏磁与磁压降较小，所设计的磁路是有效的；传统的硅油减振器对曲轴6谐次扭振幅值具有较好的抑制作用，但是对4.5谐次扭振效果的抑制不理想，反而使扭振幅值增大；与传统硅油减振器相比，采用磁流变阻尼器可使曲轴系统具有明显的变刚度、变阻尼特性.通过施加合适的电流，可使曲轴系统的扭振幅值在整个工作转速范围内达到最低. 

Torsional Vibration Characteristics of Shafting Based on MRD

Due to the narrow tuning range and match difficulty of the traditional passive silicone oil damper, a magneto-rheological damping (MRD) was proposed and designed for the semi-active control of sh afting torsion vibration based on the rheological effect of magneto-rheological fluid (MRF). According to the designed MRD structure, a mechanical model was derived and the magnetic field simulation was carried out. After that, introducing the proposed MRD into a crankshaft system, and a coupling model of the MRD-crankshaft system was established. Finally, numerical simulation was carried out based on Newmark method to obtain the torsion vibration response of the crankshaft system. And the influence of the current applying on the MRD on the torsion vibration characteristics was analyzed. The results show that the magnetic flux leakage and magnetic pressure drop outside the plate of MRF are small, and the designed magneti c circuit is effective. Though the traditional silicone oil damper has a better effect on suppressing the 6 harmonic amplitude of the crankshaft, but the effect on suppressing the 4.5 harmonic torsion vibration is not ideal, and the torsion amplitude is increased. Compared with the traditional silicone oil damper, the MRD can make crankshaft system possess obvious characteristics of variable stiffness and variable damping. Supplying a suitable current, the torsion amplitude of the crankshaft system can be minimized over the entire operating speed range.