Mode Localization And Its Application In The Flutter And Vibration Control

Aerospace structures are facing complex external environments with multi-field coupling,which make their flutter and vibration problems extremely prominent,and even affect their safety and stability.Therefore,further study of the mechanism and effective suppression methods of flutter and vibration of aerospace structures are of great significance and application value.A large number of researches show that flutter will cause the coupling and localization of structural modes,and in the structural vibration,disorders of system parameters may also cause the vibration mode localization.Consequently,this thesis mainly explores the mechanism of structural mode localization,and proposes passive vibration and flutter control methods from the perspective of structural optimization design.Firstly,by establishing dynamic models of two-span beams and obtaining the analytical solutions for their transverse vibrations,the phenomena of mode localization,frequency veering and mode exchange caused by the disorder of span length are studied.The correctness of the theoretical analysis results is verified by simulation and experimental methods.The mechanism of mode localization is revealed.Then,the axially functionally graded design is used to adjust the structural mode localization,so as to realize the passive control of structural vibration.Secondly,the phenomenon of mode localization in panel flutter is studied,and an axially functionally graded design method is proposed to realize the passive control of panel flutter.Finally,the flutter analysis method based on the aerodynamic stiffness form is introduced into the aeroelastic flutter research of high aspect ratio wings.According to the specific expression of aerodynamic stiffness matrix,the influences of relevant parameters on the flutter bound of the wings are analyzed.The results show that the passive vibration control method using mode localization can effectively suppress the vibration of the target region.The proposed axially functionally graded design method can offset the influence of aerodynamic load on the structural stiffness to the greatest extent,thus effectively improving the flutter bound of panel.The flutter bound of high aspect ratio wing has a strong dependence on the related parameters of aerodynamic stiffness,which proves once again that the aerodynamic stiffness has an important influence on the structural flutter.