Aero-thermo-elastic Dynamics And Control Study On The Plate Structures Of Flight Vehicles In Supersonic Airflow

Supersonic flight vehicle has the remarkable military value and potential economic value because of its fast cruise speed and strong penetration performance,and many countries focus on developing it.Since the plate structures,which are the basic elements in the flight vehicle,are exposed in severe environment during the cruise and the aerodynamic,thermal and mechanical loads will act on them,a large number of researchers have investigated the dynamic problems of the plate structures in supersonic airflow.Although considerable literature concerning the aero-thermo-elastic dynamic behaviors of the plate can be found,most of these publications focus on the cases with classical boundary conditions with the effects of the riveting and bonding ignored,and few researchers have studied the cases having elastic boundary conditions.At the same time,these studies mainly focus on the aerothermo-elastic dynamic problems of the supersonic plate with the simple shapes and working conditions,where a difference can be found compared with the actual engineering cases.In addition,in order to increase the critical flutter aerodynamic pressure and reduce the dynamic response of the plate structures,it is urgent to develop an efficient vibration control strategy of the plate structures in supersonic airflow.In this thesis,to investigate the dynamic characteristics of the supersonic plate structures with general boundary conditions and multi-field loads and propose the efficient control strategy,the linear and nonlinear aero-thermo-elastic analysis of the composite laminated plate in supersonic airflow,the aero-thermo-elastic analysis of the coupled composite plate and porous functionally graded material(FGM)plate in supersonic airflow,the random dynamic of the composite laminated plate in supersonic airflow and the vibration control of the composite laminated plate in supersonic airflow with nonlinear energy sink(NES)are performed,to reveal the mechanism between the elastic structures and aerodynamic,thermal and mechanical loadings.The organization of the thesis is as follows:Firstly,the first-order shear deformation plate theory(FSDT)and supersonic piston theory are employed,to formulate the energy functionals of the composite laminated plate in supersonic airflow.The governing equations of the system are obtained by using the Hamilton's principle and the solutions for the dynamic problems of the plate in supersonic airflow are obtained by using the modified Fourier method,in which the displacement components of the composite plate are expanded by the Fourier series combined with auxiliary functions to satisfy the classical and elastic boundary conditions.A considerable number of numerical examples concerning the vibration and flutter of the supersonic composite plate are carried out to show the efficiency and accuracy of the described method.The effects of the boundary conditions,thermal loads,aerodynamic pressure,fiber orientation and yawed flow angle on the flutter characteristics of the supersonic plate are analyzed in detail.Secondly,with the geometric nonlinearity of the plate structures considered,a semi-analytical vibration model of the composite laminated plate with aerodynamic,thermal and acoustic loads is formulated based on the VonKarman theory.By using the modified Fourier method,Newmark method and newton iteration method,the time domain dynamic responses of the composite plate are readily obtained.The parametric analysis is further performed to investigate the effects of the boundary constraints,thermal loads,aerodynamic pressure and acoustic loads on the dynamic response of the system,and the corresponding physical mechanism is revealed.Also,the different dynamic behaviors of the supersonic composite plate are shown and discussed in detail.Then,a unified solution is derived for the aero-thermo-elastic flutter problems of the coupled plate structures and porous FGM plates with general boundary conditions,in which the classical and elastic boundary conditions can be dealt with.The FSDT in conjunction with the supersonic piston theory to consider the supersonic flow effect is adopted to formulate the theoretical model of the heated plate structures subjected to supersonic flow.A considerable number of numerical cases are presented to show the accuracy and efficiency of the proposed method.The effects of the aerodynamic pressure,boundary condition,coupling spring,coupling location and thermal loads on the flutter characteristics of the coupled plate and the effects of the boundary condition,material property distribution,elastic foundation,temperature field,porosity volume fraction and yawed flow angle on the flutter characteristics of the supersonic FGM plate are also discussed in detail,which is important for the optimum design of plate structures and determination of safety factor.Further,the stationary/nonstationary stochastic vibration models of composite laminated plates under thermal and aerodynamic loads are established,where the temporally and spectrally stationary/nonstationary point excitation,distributed excitation and base acceleration excitation can be considered.The FSDT and supersonic piston theory are adopted to formulate the energy functionals of the system,and the governing equations are obtained based on the Hamilton's principle.The unified solutions for the cases with classical and elastic boundary conditions are achieved by using the modified Fourier method combined with pseudo excitation method(PEM).The efficiency and accuracy of the proposed model are validated by comparing the obtained results with those from the FEM and published literature.Finally,the effects of boundary constrain,thermal load,fiber orientation and aerodynamic pressure on the stochastic vibration characteristics of composite laminated plates are also discussed in detail.The experiments of the dynamic characteristics of the composite plate under random acoustic loads are carried out.By comparing the computed results with those from the experiments,the accuracy of the proposed models is validated.Finally,in order to control the dynamic responses of the composite laminated plate in supersonic airflow,the NES is further employed.The dynamic model of the composite laminated plate with NES in supersonic airflow is subsequently established.By comparing the dynamic responses of the composite plates with and without NES in supersonic airflow,the efficiency of the NES for the dynamic control is validated.The effects of the location,mass,stiffness and damping of the NES are further discussed.In this paper,a series of theoretical models are established to predict the dynamic and flutter behaviors of the composite laminated plates in supersonic airflow.Also,the effects of the aerodynamic pressure,thermal loads,acoustic loads,material and geometric parameters asymmetric on the elastic structures on the vibration and flutter characteristics of the composite laminated plates in supersonic airflow are systematically investigated.The influence laws of the aerodynamic,thermal and acoustic loads and relevant mechanisms are revealed.Above all,the discussion and the revealed mechanisms in this thesis are of great significance in science and engineering.