Buckling modes and failure of test specimens from fiber-reinforced composites with a [0∘]s layup under axial compression. Theory and experiment

The analytical solutions for the problems of macroscale flexural-shear and purely transverse-shear buckling modes of test specimens made of fiber-reinforced composites with a [0∘] s layup ( s denoting the number of laminas) were analyzed, as well as the problems of mesoscale transverse-shear buckling modes of their peripheral layers under axial compression. Composite materials characterized by a physically nonlinear relationship only between transverse tangential stresses and the corresponding shear strains were examined. The solutions were obtained using three variants of linearized equations of the equilibrium in a perturbed state: based on the simplest refined S.P. Timoshenko’s model; from a linear approximation of the deflection and a cubic polynomial approximation of the axial displacements in the transverse coordinate with the preliminary satisfaction of the boundary conditions for tangential forces (the first refined version of the theory; Reddy–Nemirovsky model type); and without the preliminary satisfaction of such conditions (the second refined version of the theory). The physical nonlinearity of the material was incorporated in the linearized equations following the Shanley concept by introducing the tangential shear modulus. The theoretical data were compared with the experimental results.