DYNAMIC INSTABILITY OF SHEAR-DEFORMABLE LAMINATED PLATES

The dynamic instability of antisymmetric angle-ply and cross-ply laminated plates, subjected to periodic in-plane loads P(t) = P(s) + P(d) cos-omega-t, is investigated within the high-order shear deformation lamination theory, where the motion is governed by five partial differential equations. Using the method of multiple-scale, analytical expressions for the instability regions are obtained at omega = OMEGA-j +/- OMEGA-i, where OMEGA-i are the natural frequencies of the system. It is shown that, besides the principal instability region at omega = 2-OMEGA-1 (OMEGA-1 is the fundamental frequency), other cases of omega = OMEGA-i + OMEGA-j, related to the first mode, can be of major importance and yield a significantly enlarged instability region.