The R-functions theory is applied to study free vibration and dynamic instability of the symmetrically laminated
plates subjected to combined static and periodic axial forces. It is assumed that subcritical state of the plate
may be inhomogeneous. Theoretical formulation is made on the classical plate theory (CTP). The developed
approach is based on combined application of Ritz’s method, Galerkin procedure, R-functions theory and
Bolotin’s method. The buckling, instability zones and response curves for laminated plate with different
external cutouts are presented and discussed. Effects of plate geometrical parameters, parking of layers,
mechanical characteristics of the material on buckling, natural frequencies and parametric resonance are also
studied