Flutter Analysis Of Swept Wing

During the flight,the interaction between the structure of wing and the airflow makes the wing flutter phenomenon very significant.At present,most of the research and analysis of wing flutter are based on the model of long straight wings,and the aerodynamic force is mostly nonlinear.In order to improve the high speed performance of modern large transport aircraft,most of wing structures adopt the high-aspect-ratio swept wing,which can increase the critical speed of wing flutter.With the widespread use of high-aspect-ratio swept wing in modern large transport aircraft,it is very important to study the flutter characteristics and response analysis of swept wings.In this regard,the following research work is done in this paper.(1)The structural motion model of the swept wing is derived by using Hamilton’s variational principle without considering the wing store;the swept wing aerodynamic model is obtained by modifying the Theodorsen aerodynamics,so that the system equations of motion of the swept wing can be established and dimensionless treatment is performed.(2)The first fourth order vibration functions of the swept wing is solved considering the effect of the tip-root ratio,and the system equations are discretized by Galliakin method.(3)The equations of the swept wing system are solved by the V-g method,and numerical simulations of different wing models are carried out by matlab to study the effect of order change on the flutter critical velocity;a wing model is used to calculate the flutter critical velocity,and buckling analysis and nonlinear response analysis are carried out to study the flutter characteristics of the swept wing.(4)Considering the effect of wing suspension,a swept wing model with external suspension system is rederived and established.Numerical simulations are carried out for a wing model to calculate the effects of different store parameters and swept angles on the critical velocity and frequency of flutter,and to perform buckling analysis and nonlinear response analysis.The results of numerical simulation show that the position of the swept wing elastic axis,the aspect-ratio,the position of the center of gravity and the swept angle have significant effects on the flutter characteristics.The store parameters have significant effects on the flutter characteristics of the wing.When the speed is greater than the flutter speed,the swept wing will undergo a series of complicated motion and finally enter the chaotic motion state.