Mixed finite-element model for thick composite laminated plates

Abstract

A layerwise, mixed, 18-node finite-element (FE) model has been developed to analyze laminated composite plates by using the minimum potential energy principle. Continuity of transverse stresses and displacement fields has been enforced through the thickness direction, Z, of a laminated plate by considering six degrees-of-freedom (three displacement components in the coordinate axes directions and three transverse stress components tau(xz), tau(yz), sigma(z)) per node. Because the transverse stress components have been invoked as nodal degrees of freedom by using the fundamental elasticity relationship between the components of stress and displacement, the model has an added feature of maintaining the fundamental elasticity relation among the stress, strain, and displacement fields throughout the elastic continuum, which has not been observed in various mixed formulations available in the literature. Results obtained by using the present FE model have shown excellent agreement with the available elasticity solutions for thin and thick composite laminates as well as sandwich plates.