C 0 Zig-Zag Finite Element for Analysis of Laminated Composite Beams

Abstract

A new C⁰ finite element for accurate analysis of laminated composite beam structures is developed. The element formulation is based on a quadratic zig-zag layerwise theory developed previously by the writers. The theory assumes a zig-zag distribution of the in-plane displacement field through the thickness and satisfies the interlaminar shear stress continuity across the layer interfaces. In developing the finite-element formulation, the shear strain fields are made field consistent, and thus the shear locking phenomenon is eliminated. A new transverse normal strain is derived by assuming the transverse normal stress to be constant through the thickness of the laminate. This assumption is shown to remove Poisson's ratio stiffening. The results obtained from the present finite element are found to be in good agreement with exact elasticity solutions available for simply supported beams. A multisublaminate approach that is simple to implement with the present element is shown to improve the predictions of the present model for complex laminated structures.