Study of Stresses and Deformations in Sandwich Plates with Anisotropic Facings

Abstract

HIS paper deals with the determination of the stresses and deformations in a sandwich plate with generally orthotropic facings and an isotropic core subjected to a uniform static lateral load. A numerical study of the effect of facing anisotropy on the stress and strain components and on the core and facing strain energies is carried out. It is shown how the introduction of facing anisotropy affects both the magnitude and distribution of stresses and strains and how the core strain energy may be widely altered by varying the elastic axes of the facing material. Several papers have appeared in the literature dealing with anisotropic plate and shell structure analysis. Among the more recent of these are papers by Ashtpn, 1 Whitney and Leissa2 and Whitney and Pagano.3 None of these, however, contains information concerning the effect of anisotropy on the distribution of stresses, strains and displacements within the structure. For this study, governing equation derived by Kingsbury and Pavacic4 for sandwich plates with thin anisotropic facings are used. These equations were derived using the usual assumptions of sandwich plate theory,5 with the exception that the membrane facings are constructed from a generally orthotropic rather than isotropic material. The angle 0, between the plate edges (x, y) and the facing principal elastic axes (a, j8) then serves as a convenient parameter for defining facing anisotropy. The sandwich plate consists of upper and lower facings of thickness t and a core of thickness h. The plate has widths a and b with jc, y directions, respectively. The inplane displacement components u and v, and transverse displacement w at any point in the structure are given by u = u0(x, y) + £(*, y)z, v = v0(x, y) +'£(x, y)z9 w = w(x, y) where £ and f are the rotation components of normals to the middle surface in the x-z and y-z planes. The plate is simply supported on all edges and each of the facings are constructed of the same orthotropic material and