Analysis On Dynamic Characteristics Of Honeycomb Sandwich Panels With Zero Poisson's Ratio Simply Supported On Four Edges

Honeycomb sandwich structure is light in weight,high in strength,high in rigidity and easy to form.It has been widely used in transportation,aerospace and other fields.Honeycomb sandwich structure with zero Poisson's ratio is an important material for intelligent aircraft with its special in-plane unidirectional deformation capability.In this paper,the equivalent structural parameters of the honeycomb core layer are deduced,and the theoretical and numerical studies on the free vibration characteristics and nonlinear forced vibration characteristics under the four-sided simply supported condition are carried out.The main work and achievements of the thesis are as follows:(1)According to the classical Euler beam theory,theoretical calculation formula of the equivalent elastic modulus Ex?Ey?Ez and the Poisson's ratio vxy?vyx of the honeycomb core structure are derived.Considering the influence of the bending moment of internal force and shearing force of the structure,the equivalent shear modulus Gxy,in the plane xoy is derived by the bending deformation theory.The theoretical calculation formula of the equivalent shear modulusGxz?Gyz in the plane xoz and plane yoz is derived by the energy method.The equivalent density of the honeycomb core structure is derived from mass conservation.The finite element simulation of the honeycomb core layer of honeycomb sandwich panel with zero Poisson's ratio is carried out to verify the accuracy of the above theoretical formula.(2)The problem of lateral bending free vibration of honeycomb sandwich panel with zero Poisson's ratio simply supported on four edges is studied.Based on the classical laminated plate theory,first-order shear plate theory and Reddy's shear deformation plate theory,the vibration differential equation of honeycomb sandwich panel is derived by Hamilton variational principle.Under boundary conditions of simply supported on four edges,the frequency equation of the honeycomb sandwich panel is derived respectively.The theoretical calculation results are compared with the ANSYS simulation results,and the influence of the structural parameters of the honeycomb sandwich panel on its natural frequency is analyzed based on Reddy's shear deformation plate theory.(3)The nonlinear forced vibration of honeycomb sandwich panel with zero Poisson's ratio simply supported on four edges is studied.Based on Reddy's shear deformation plate theory and nonlinear geometric relationship,the nonlinear vibration differential equations of honeycomb sandwich panel with zero Poisson's ratio are derived by using the Hamilton variational principle.The nonlinear vibration differential equations are discretized by Galerkin method.Considering the influence of lateral damping,the fourth-order Runge-Kutta method is used to numerically simulate the nonlinear vibration characteristics of honeycomb sandwich panels with zero Poisson's ratio under harmonic excitation.