Three-Dimensional Dynamic Stress Analysis of Sandwich Panels

A layerwise geometrically nonlinear theory for a thick sandwich plate was developed by introducing assumptions on a variation of transverse strains in the thickness direction of the faces and the core of the plate. An effect of transverse extensibility or compressibility of the core and the face sheets is taken into account, and the terms associated with transverse shear strain of the face sheets and the core are included into the expression for the strain energy. Displacements, obtained by integration of the strain-displacement relations, depend nonlinearly on a coordinate in the thickness direction, and are continuous at the boundaries between the face sheets and the core. The nonlinear von-Karman strain-displacement relations are used in order to provide a representation of the moderately large rotations. The in-plane stresses are computed from the constitutive relations in each ply of the face sheets, using each ply`s material properties, and the transverse stresses are computed by substituting the in-plane stresses into equations of motion and by integrating the equations of motion.