Vibration And Buckling Of Graphene-reinforced Functionally Graded Dielectric Circular Plate

Advanced materials are the precursors and carriers of scientific and technological progress.Graphene reinforced functionally graded dielectric materials are new advanced materials that meet the requirements of the rapid development of modern science and technology for the performance-function-intelligence integration of engineering materials The reinforcement of graphene greatly improves the mechanical,electrical and thermal properties of dielectric materials.It also overcomes the problems of delamination,cracking and thermal stress concentration in high temperature environment caused by the discontinuity of the interface of traditional laminated smart composites.With many advantages such as designability and smart controllability.The studies of mechanical behaviors are key issues in safety and design,function and optimization,intelligence and control in the applications of these composite material.In this thesis,widely used circular plates in engineering are chosen as the structure to study the vibration and buckling characteristics of graphene reinforced functionally graded dielectric circular plates.Firstly,the equivalent materials parameters of the composite circular plate are obtained based on effective medium theory(EMT)and linear mixture rule model considering various complex factors such as gradient properties of the material,dielectric properties,imperfect bonding between graphene and matrix material,interfacial electron tunneling,MaxwellWagner-Sillars(MWS)polarization and percolation threshold of the composite.Secondly,based on the classical plate theory,the free vibration and buckling characteristics of the plate are studied,and the governing differential equations for the vibration and buckling of the circular plate are derived by Hamiltonian principle and the principle of virtual work,respectively.And the quantitative results of the dimensionless natural frequencies and the buckling critical load are obtained by numerical solution using the differential quadrature method.Finally,the numerical results are also discussed in detail,and the effects of the volume fraction and geometry of graphene,gradient distribution pattern,percolation threshold,dielectric permittivity,gradient slope factor,as well as thickness variation of interphase layer on the natural frequencies and critical loads of the circular plate are analyzed.The influences of the distribution pattern and volume fraction of graphene,as well as the parameters such as external load,control voltage,and structural geometry on the natural frequencies and critical loads are revealed.The results show that the vibration and buckling characteristics of the plate can be actively adjusted by changing the distribution parameters of graphene or the properties of the applied control voltage.It can also be concluded that the vibration and buckling characteristics of the composite circular plate with the FG-X model are optimal.The research results of the thesis give the main influencing factors of the free vibration and buckling characteristics of the composite structures,which can provide theoretical reference for the optimal design,dynamics and stability analysis of a class of intelligent structures under complex environment.