Research On Vibration Suppression Method Of Aero-engine Rotor Based On Stack Assembly Optimization

As the "pearl in the crown of industry",aviation engine directly affects the working efficiency,safety and economy of aircraft,so it is an important standard to measure the level of national industry,science and technology and national defense.More than 70% of the total engine faults are caused by vibration,which has always been the bottleneck in the independent development of aviation engines in China.Only by solving the vibration problem can the performance and reliability of the engine be improved.At present,the influence mechanism of error on vibration response is not clear,and no theoretical relationship has been established from the control index of key assembly process parameters to the vibration index evaluating assembly quality level.Therefore,it is necessary to study the influence mechanism of process parameters and assembly process parameters on high-speed vibration response of rotors and establish the combined rotor vibration model to realize vibration suppression of high-voltage combined rotor.In this paper,a rotor vibration suppression method based on stack assembly optimization is proposed to establish a rotor vibration measurement model so as to improve the rotor vibration of aero-engine from the root in the assembly process.This method can realize the joint control of bending stiffness and unbalanced excitation force of composite rotors by building the stacked assembly model of composite rotors,so as to realize the prediction and optimization of rotor vibration characteristics.In this paper,the influence of stacked assembly on bending stiffness and unbalanced excitation force of composite rotors is deeply studied,and a vibration measurement and adjustment model based on stiffness and unbalanced excitation force is established.The effectiveness of vibration suppression method of composite rotors based on stacked assembly is verified by experiments.The main research contents include:Firstly,a composite rotor stiffness measurement model based on stack assembly is established.The relationship between single stage rotor error and flexibility is clarified by analyzing the regulation principle of bending stiffness of composite rotor.The law of transfer and amplification of rotor flexibility vector during assembly is studied to establish a prediction model of bending stiffness of composite rotor considering errors.A combined rotor stiffness optimization method based on stack assembly optimization is presented.Secondly,the rotor unbalance excitation force measurement model based on stack assembly is established.The reason and regulation principle of unbalance excitation force of composite rotor are clarified.The prediction model of initial unbalance excitation force is established by studying the transfer and amplification of rotor unbalance excitation force vector during assembly.An optimization method for unbalanced excitation force of composite rotors is presented.Thirdly,the combined rotor vibration suppression method based on stiffness and excitation force measurement is studied.The influence mechanism of bending stiffness and unbalanced excitation force on the vibration of the rotor are clarified.The stiffness matrix considering the error and the unbalanced excitation force matrix are established to establish the rotor finite element steady-state motion equation.Rotor vibration prediction can be achieved by solving the high-speed vibration response of the rotor.A rotor vibration suppression method based on the joint control of stiffness and unbalanced excitation force is presented to realize the vibration suppression of aero-engine rotor.Finally,an experimental study on vibration suppression of rotor of an aero-engine is carried out.An aero-engine rotor test piece is developed and a dynamic vibration measurement system is built to measure the vibration response of the combined rotor under different assembly strategies.It is proved that the maximum error between the measured vibration amplitude and the theoretical predicted value of the directly assembled combined rotors is 15.5 ?m at the rotation speeds of 4000 rpm,5000 rpm,6000 rpm and 7000 rpm,which indicates that the theoretical model established in this paper can predict the vibration response of the combined rotor.The vibration response of composite rotors assembled with the optimal assembly strategy is 22.5% lower than that of composite rotors assembled with the direct assembly strategy.This indicates that the rotor vibration suppression method proposed in this paper can effectively improve the assembly quality of the rotor and suppress the vibration of the rotor.