Study On Dynamic Characteristics Of Multi-Stage Bladed Disk System

Aero-engine is the heart of aircraft,its performance is directly related to the performance and safety of aircraft.With the development of science and technology and the need of civil aviation,the development of aero-engine is becoming more and more perfect.The compressor bladed disk system is an important component of aero-engine,which is composed of multi-stage bladed disk system,and the coupling between the bladed disk and the bladed disk can’t be ignored.In this paper,the multi-stage bladed disk system is taken as the research object,the dynamics model of the multi-stage bladed disk system is established,the vibration localization characteristics are analyzed,and the optimization analysis model and algorithm of vibration reduction are established.The thesis mainly includes the following contents:Firstly,the reduction modeling method of the multi-stage bladed disk system is studied.Based on the substructure modal synthesis method,the inter-stage coupling characteristics of the multi-stage bladed disk system are considered.The substructure reduction model and the whole model of the multi-stage bladed disk system are established using ANSYS,and the inherent characteristics of the two models are analyzed.The results show that the errors between the dynamic frequency parameters of each order mode of the substructure model and the whole model can be ignored,which meets the calculation requirements.The lumped parameter model of the multi-stage bladed disk system is established,which provides the basis for verifying the accuracy of the substructure model.Secondly,the modal localization characteristics of the mistuned multi-stage disk system are studied,the displacement and strain energy distribution of the disk system are considered,the modal localization degree caused by the mistuning of the contact boundary between stages is analyzed,and the vibration characteristics of the substructure model and the centralized parameter model are compared under the condition of mistuning.The results show that the maximum displacement amplitude of the multi-stage disk system increases obviously due to parameter mistuning,and modal localization occurs.When the stiffness and mass mistuning are 5%,the maximum amplitude and modal localization degree of the system reach the extreme value.Thirdly,the response localization characteristics of the mistuned multi-stage bladed disk system are studied.According to the results of modal analysis,the frequency of600Hz～1600Hz is swept,the excitation order and softening effect are considered,and the vibration response localization caused by the mistuning is analyzed.The results show that the maximum vibration amplitude of the third stage of each excitation order is the highest,and reaches the extreme value when the excitation order is 2.It is found that the softening effect has a certain influence on the amplitude of the system.Finally,the vibration reduction optimization method of the mistuned multi-stage bladed disk system is studied.According to the vibration response results of the mistuned bladed disk system,the local vibration reduction optimization algorithm of the mistuned blade disk vibration is established based on the intelligent optimization algorithm and the substructure reduction model of the bladed disk system.The results show that the optimization algorithm of random slightly worn bladed mass has a certain effect of vibration reduction,saving a lot of computer time,and the calculation efficiency is high.The snake optimization algorithm based vibration reduction optimization method can obtain the global optimal solution through a certain number of iterations,and can effectively reduce the degree of vibration localization of the mistuned blade disk system.