An efficient four-variable I-L nonlocal static model of unsymmetrical sandwich rectangular plate with laminated facings

Abstract This paper presents a new, simple, containing only four unknown functions, individual-layer, static model for rectangular sandwich plate unsymmetrical with respect to its middle plane. The shear strains in the outer layers of the plate are neglected while the shear strains in the middle layer are variable and equivalent to zero on its outer surfaces. Local constitutive models of the layers consistent with the assumed kinematics are derived. A detailed analysis of all partial problems is presented. In order to determine the unknown functions, appearing in the kinematic model assumed, one needs to solve a set of three coupled partial differential equations and separately the fourth governing equation that contains only one unknown function. In the case of the plate symmetrical about its middle plane only two uncoupled partial differential equations for the bending problem must be solved. Deflections predicted by the present model for a symmetrical sandwich plate are compared with counterparts, existing in the literature, predicted by two theories that include flexibility of the middle layer of the plate. Good agreement of these results has been obtained.