On evaluation of transverse stresses in layered symmetric composite and sandwich laminates under flexure

Abstract

This paper attempts to evaluate the transverse stresses that are generated within the interface between two layers of laminated composite and sandwich laminates by using Co finite element formulation of higher-order theories. These theories do not require the use of a fictitious shear correction coefficient which is usually associated with the first-order Reissner-Mindlin theory. The in-plane stresses are evaluated by using constitutive relations. The transverse stresses are evaluated through the use of equilibrium equations. The integration of the equilibrium equations is attempted through forward and central direct finite difference techniques and a new approach, named as, an exact surface fitting method. Sixteen and nine-noded quadrilateral Lagrangian elements are used. The numerical results obtained by the present approaches in general and the exact surface fitting method in particular, show excellent agreement with available elasticity solutions. New results for symmetric sandwich laminates are also presented for future comparisons.