A model for laminated composite beams based on a novel zig-zag theory

Abstract

We develop a new model called C-311 for laminated composite beams based on a new zig-zag theory that is firstly proposed in this paper. The in-plane displacement field of the model includes two parts: part one is regarded as the global displacement field which is made of third-order polynomial about z, part two is the local displacement field which is the new zig-zag theory. By satisfying inter-laminar transverse stress continuity and the free surface conditions, the local displacement unknown variables can be eliminated, and the final displacement field should be expressed by the fixed number of unknown displacement variables. For testing the ability of C-311, the classical example about a simply supported laminated beam is investigated under mechanical loading in this paper. In comparison with other models of laminated composite beams, the numerical results show that the present model can give more accurate analysis, and are closer to the exact solutions. Especially the accurate transverse shear stresses are able to be directly obtained from the constitutive equations without any processing, and that is never done for other zig-zag models existing in the literature and benefit for practical engineering applications in the finite element method.