Flutter Analysis Of Plate And Experimental Research

In this paper,the flutter and thermal flutter of a panel are studied.The flutter of the thin plate in a low speed flow is investigated by wind tunnel experiment.The main research progress and results of this paper are as follows.(1)Using the Lighthill piston theory to calculate the aerodynamic force,the differential equations of motion is established.Then,the flutter theory is analyzed by V-g method after transforming the differential equations into the modal space.(2)Nonlinear flutter analysis of two-dimensional panels in supersonic airflow is carried out.The aerodynamic thermoelastic equation of the system is established,and the Galerkin method is used to discretize the equation.Then,the stability of the system is analysised to find the boundary conditions of static buckling instability and dynamic flutter instability.(3)Linear flutter analysis of thin plates is carried out.The mechanical model of a thin plate with two sides fixed and other two sides free is established.The natural frequencies and vibration modes of this plate are calculated.The influence of aerodynamic heating is not only worked for the properties of structural materials but also lead to thermal stress.In the finite element analysis,thermal buckling of thin plates is easy to take place.The stiffness of the thin plate is increased by applying the intial stress to the sheet.The effects of different temperature on the flutter speed of the thin plate are studied.(4)The flutter of the panel in the low speed flow is studied by tunnel experiments.According to the numerical simulation,the experimental device is designed for the experiment.The relationship between the actual tensile length and the strain is verified by the strain experiment.The actual physical properties of the thin plate are verified by the modal experiment.Finally,the study on the fluttering thin plate is carried out by the wind tunnel experiment.It is found that the amplitude of the thin plate is smaller when the flow velocity is higher.Due to the effects of in plane stress lead by difference of pressure in different side of the plate,the flutter speed increases.Therefore,the flutter characteristics of thin plates with prestress are considered.The velocity range of flutter speed is found at low speed.