Large amplitude free vibration of simply supported antisymmetric cross-ply plates

The presence of bending-extension coupling in antisymmetric cross-ply plates results in the cubic nonlinear term in addition to the fourth-power term in the energy balance equation. The existence of this term does not allow two real, equal, and opposite roots while solving the energy balance equation for maximum amplitude position unlike in isotropic, orthotropic, symmetric cross-ply and symmetric and antisymmetric angle-ply plates. A direct numerical integration method has been proposed to study the large amplitude free vibrations of such plates. It is also shown that the extensively used perturbation method fails, depending on the severity of the bending-extension coupling term. Large amplitude free vibration characteristics are obtained in this paper for several configurations of antisymmetric cross-ply plates. (Author)