Stability Research Of Abrupt Vibration Of Flexible Rotor Caused By Limiting Structure

Vibration control is one of the important parts which compose rotor safety and stability research.Displacement damper is one of the useful vibration control methods,it uses the collision and friction between rotor and limiting devices to reduce abnormal vibration,which transform the rotor dynamic into a high coupling,strongly nonlinear and astable problem.A new type of limiting structure is applied between the inner and outer rotor of a certain model of dual-rotor turboshaft engine,which hasn’t been deeply studied in domestic.Therefore the study on rotor-rotor rub impact vibration characteristics has important theoretical significance and engineering value.The structure of this paper is organized as follows:1.We set up a 5-fulcrum dual-rotor system,presented the aero-engine dynamic modeling methods and calculated the parameters of rolling bearings,squeeze film damper and squirrel-cage elastic support.We adopted finite element method to independently construct dual rotors,analyzed their critical speeds and dynamic characteristics without limiting structure.2.Based on the state of relative motion between inner and outer rotors,we created a rubbing force model which effected both rotors.Using numerical integration method we calculated the dynamic response of rubbing rotors,and we observed the difference of kinestates generated by different relative displacement between dual rotors.We studied the influence of rubbing interval,contacting material and installation site on rubbing rotor dynamic characteristics and we proposed an optimization criteria.3.We studied the influence of working frequencies of outer rotor on dynamic response.We set up a variable speed rotor system model and calculated the dynamic response under different accelerations,in order to observe the detachment of inner rotor against the limiting structure.