On the Dynamic Stability of Multilayer Sandwich Plates

The dynamic stability of homogeneous isotropic plates subjected to time-dependent periodic in-plane loads has been the subject of several investigations in recent years. Plates other than homogeneous and isotropic have been less fully explored. This paper is concerned with the case in which the plate is constructed of several alternating soft and hard layers. Although each layer may serve a different purpose (structural, thermal, etc.), the interaction between these layers makes it desirable to take full advantage of their load-carry-: ing capacity. In investigating the dynamic stability of such multilayer sandwich plates, one may be justified in neglecting in-plane inertia and damping when considering loads with certain frequency characteristics. In other ranges of frequency, a correct description of the stable and unstable regions can only be obtained by including the influences of in-plane inertia as well as damping in the formulation of the problem. A theory that accounts for all of these effects is presented for multilayer sandwich plates. The plate thickness consists of (k) orthotopic soft core layers sandwiched between (K) hard isotropic membrane layers, each of which This paper presents the results of one phase of research carried out at the Jet Propulsion Laboratory under Contract NAS7-100, sponsored by the National Aeronautics and Space Administration.