Aeroelastic Studies On The Rudder Of Hypersonic-glide Vehicle

Aeroelastic problem is one of the key technologies during the hypersonic vehicles overall design.This dissertation takes the boost-glide tactical missile within the atmosphere as the research object,of which the flutter characteristics of the air rudder surface in supersonic condition is put into the main research effort.Compared with conventional aircrafts,new generation of hypersonic vehicles like boost-glide tactical missiles prefer lighter materials and thin-walled structure,take the slender body,lifting body and complete/partial wave-riders as the main choices of the aerodynamic layout design.All these particular characteristics mentioned above make the aero elastic problem highly different from the conventional aircrafts.Flutter,which is mostly focused among numerous aeroelastic problems,typically happen in few seconds to destroy the structure,or worse to disassemble the aircraft.Research results in this paper will have a great value on aircraft design.Flutter dynamic model of rudder surface is established,including the structural motion equation of 2-D wing,two methods to calculate unsteady aerodynamic respectively named as the piston theory and supersonic dipole grid method,and the commonly used P-K flutter analysis method.Calculation examples of plane wing surfaces are given to validate the model.Hypersonic aerothermoelasticity are investigated.Adopting the 3-D perfect gas model and heat conduction differential equation,numerical simulation of the surface dynamic heat is established to calculate the temperature distribution,which is farther used to analyze affections of the anti-heat cover structure to the oscillation and flutter characteristics of rudder.Simulation results demonstrate that thermal protection structure can appreciably decrease the natural vibration frequency under constant temperature environment,and dramatically increase the flutter speed under aerodynamic heating environment.Rudder flutter characteristics influenced by the rocket body vibration are investigated.The transverse vibration equation is established to obtain the dynamic response of the rocket body functioned by constant thrust.The third chapter takes the plane wing surface as example,adopts the second order piston theory to establish the dynamic equation of 3-D rudder surface and to calculate the unsteady dynamic force upon the wing,discretizes the equation by Bubnov-Galerkin method,and solves the equation by the fourth order Ronge-Kutta method.Results show that along with the fuel consumption,the natural frequency of vibration increases and the flutter speed slightly decreases.Whereas when the flight altitude changes quickly,air density affects much more than the fuel consumption on the flutter speed.The research work of this dissertation focus on the influence of the aerodynamic heat,the thermal protection structure and the rocket vibration to the rudder flutter speed,and the conclusions can help to increase the flight rudder speed and choose the statue parameters during the design process.