Panel Flutter Analysis With Thermal Effect Under Unsteady Aerodynamics

As a typical aeroelastic phenomenon,panel flutter which usually occurs when the aircraft flying at a high-speed has been a problem for a long time. And it is especially prominent for the modern high-speed aircraft. When the March number of the aircraft flights is quite large, the aerothermal effect factor should be considered for the reason that it affects the structural stiffness of the panel, and finally affects the critical flutter speed of the panel. Moreover, the panel flutter phenomenon will directly influence the service life of the aircraft and its flight stabilities. In view of its important engineering significance and scientific value, a lot of researches on the panel flutter have been done. The influences of the aerothermal effect factor and the airflow speed factor on the panel flutter are mainly considered in this paper, which finally provides the important theory basis for the control of this phenomenon.By taking metal material flat panel as a research object, its flutter phenomenon in high-speed environment is analyzed. The main contents are: first, the common used unsteady aerodynamics model in panel flutter is introduced. And the unsteady aerodynamics calculation model used in this paper according to Piston- theory is deduced; second, the homogeneous temperature field model of the material properties varying with the temperature which causes the thermal effect is establish. Based on the Mindlin - Reisser plate and shell theory of continuum mechanics, the geometric relations and stress -strain constitutive relation of the flat panel are established; The dynamics equation of the general flat panel is derived by utilizing the energy theory; third, by using the finite element method based on the MIN3 element, the interpolation functions are determined and the whole function of displacement field is derived. By using the unsteady aerodynamic model derived in the above proceeding, the dynamical equation of metal material panel is finally obtained; last, the dynamic equation of the panel is solved by using the numerical method and the influences of the various factors on the panel flutter are analyzed. in the analysis, the influence of temperature on the amplitude of the vibration before the panel's failure, the natural frequencies and flutter frequencies as well as the critical flutter velocity of the flow is mainly considered, and the influences of the flow velocity on the amplitude of vibration before the panel's failure and natural frequencies are also considered.