A new extended higher-order sandwich panel theory (EHSAPT) for orthotropic
elastic sandwich plates is formulated. This new theory extends the one-dimensional
extended higher-order sandwich panel beam theory to two dimensions and applies it
to plate structures. In this theory, the compressibility of the soft core in the
transverse direction is taken into consideration. The in-plane displacements are
third-order and the transverse displacement is second-order in the transverse
coordinate respectively. This arrangement allows the theory to take the axial, shear
and transverse normal stresses in the core in consideration. In order to derive the
governing equations and associated boundary conditions, eleven generalized
coordinates are considered. Each face sheet has three generalized coordinates (two
in-plane and one transverse displacement respectively) and the core has five
generalized coordinates which include three displacements and two independent
rotations. The governing equations and boundary conditions are derived using a
variational approach such that all core/face sheet displacement compatibility
conditions are satisfied.
