Research On Vibration Characteristics Of Composite Honeycomb Sandwich Panels

Lightweight composite honeycomb sandwich panels have been widely used in various fields such as automobile manufacturing,ship and ocean engineering,aerospace and other modern industries because of their advantages of high specific strength,specific modulus,impact resistance and outstanding design ability.Due to the particularity of their working environment,these structures are often subjected to vibration loads.Therefore,it is of great significance to study the dynamic characteristics of honeycomb sandwich structures.Based on the first order shear theory,the finite element formula of laminate plate is derived,and the finite element program of quadrilateral eight node isoparametric plate element is written in FORTRAN language,and then the static displacement,stress of each layer and natural modes of laminated plates are calculated,and the effects of the aspect ratio of length to thickness,modulus ratio and the number of layers on the natural frequency of symmetric and antisymmetric orthogonal ply laminates plates are also discussed.For the typical Honeycomb sandwich structure,based on the Y-type cell element model,considering the bending,expansion and shear deformation of the Honeycomb cell wall,the equivalent mechanical parameter expression of the double-thickness hexagonal Honeycomb core is derived using the Timoshenko beam theory.And the correctness of the theoretical formula is proved by the finite element numerical simulation of the characteristic cell.On the basis of the Resineer theory,and considering the shear strain of core layer,the free vibration control equation of the orthotropic rectangular honeycomb sandwich plate is derived,and the exact solution of the natural frequency under the condition of simply supported is given.Then the theoretical calculation is compared with the numerical and experimental results,and the rationality of the method is verified.On this basis,the influence of various characteristic parameters of honeycomb sandwich plate on its natural frequency is discussed.Finally,the forced vibration response of the composite sandwich plate was analyzed in time domain and frequency domain respectively,and the influence of damping ratio,excitation frequency and the thickness of the core ratio on the response characteristics of the forced vibration is discussed.