A zigzag model for laminated composite beams

In the present work, a zigzag model for symmetric laminated beam is developed. This model uses a sine term to represent the non-linear displacement field across the thickness as compared to a third order polynomial term in conventional theories. Transverse shear stress and strain are represented by a cosine term as compared to parabolic term. This model satisfies displacement and transverse shear stress continuity at the interface. Zero transverse shear stress boundary condition at the top and bottom of the beam are also satisfied. The numerical results indicates that the present model predicts very accurate results for displacement and stresses for symmetric cross-ply laminated beam, even for small length to thickness ratio. The results are also compared with a simplified theory of same class.