Thermoelastic bending analysis of functionally graded sandwich plates using a new higher order shear and normal deformation theory

A new higher order shear and normal deformation theory is developed to simulate the thermoelastic bending of functionally graded material (FGM) sandwich plates. By dividing the transverse displacement into bending, shear and thickness stretching parts, the number of unknowns and governing equations for the present theory is reduced, significantly facilitating engineering analysis. Indeed, the number of unknown functions involved in the present theory is only five, as opposed to six or even greater numbers in the case of other shear and normal deformation theories. The present theory accounts for both shear deformation and thickness stretching effects by a sinusoidal variation of all displacements across the thickness, and satisfies the stress-free boundary conditions on the upper and lower surfaces of the plate without requiring any shear correction factor. The sandwich plate faces are assumed to have isotropic, two-constituent material distribution through the thickness, and the material properties are assumed to vary according to a power law distribution in terms of the volume fractions of the constituents. The core layer is still homogeneous and composed of an isotropic ceramic material. The influences of thickness stretching, shear deformation, thermal load, plate aspect ratio, side-to-thickness ratio, and volume fraction distribution on plate bending characteristics are studied in detail. Numerical examples are presented to verify the accuracy of the present theory. The present study is relevant to aerospace, chemical process and nuclear engineering structures which may be subjected to intense thermal loads.