Assessment of zigzag theory for static loading, buckling, free and forced response of composite and sandwich beams

An efficient zigzag one-dimensional (1D) theory of laminated beams is assessed by comparison of analytical solutions of simply supported beam with exact 2D elasticity solutions for static patch load, natural frequencies, harmonic transverse load with sinusoidal longitudinal variation and buckling under axial load. These results for a highly inhomogeneous test beam, symmetric composite beam, anti-symmetric composite beam and sandwich beam are also compared with first order (FSDT) and third order (TOT) shear deformation theories. The effect of the laminate lay-up and the thickness-to-span ratio on the accuracy is assessed. The zigzag theory yields much more accurate results than the TOT and FSDT. (C) 2003 Elsevier Ltd. All rights reserved.