A COMPARISON OF 9-NODE AND 16-NODE QUADRILATERAL ELEMENTS BASED ON HIGHER-ORDER LAMINATE THEORIES FOR ESTIMATION OF TRANSVERSE STRESSES

Abstract

C-degrees finite elements based on a set of higher-order theories are projected to provide reliable predictions for interlaminar stresses in layered composite and sandwich laminates. These theoretical-cum-computational models incorporate laminate deformations which account for the effects of transverse shear deformation, transverse normal strain/stress and a nonlinear variation of inplane displacements with respect to the thickness coordinate, thus eliminating the need for shear correction coefficients. The inplane stresses are evaluated via constitutive relations, while the interlaminar stresses are evaluated by using the equilibrium equations. 16 and 9 noded Lagrangian selectively integrated isoparametric elements are used in this study. The present results, when compared with available elasticity and closed-form laminate solutions, show good agreement. New results for sandwich laminates are also presented which may serve as a benchmark for future investigations.