DYNAMIC INSTABILITY OF ANTISYMMETRIC LAMINATED PLATES

The dynamic instability of antisymmetric angle-ply and cross-ply laminated plates, subjected to periodic in-plane loads P(t) = P0 + P1 cos θt, is investigated. Within the classical lamination theory, the motion is governed by three partial differential equations. By using the method of multiple scales, analytical expressions for the instability regions are obtained at θ = Ωi + Ωj, where Ωi are the natural frequences of the system. It is shown that in some cases, beside the principal instability region at θ = 2Ω1, where Ω1 is the fundamental frequency, other cases of θ = Ωi + Ωj can be of major importance, and the final instability regions are significantly enlarged. © 1992.