POSTBUCKLING OF LAMINATED COMPOSITE AND SANDWICH PLATES AND SHELLS - ON THE SIGNIFICANCE OF THE FULFILLMENT OF STATIC INTERLAYER CONTINUITYCONDITIONS

Two structural models of laminated composite and sandwich plates and s hells are presented and used to study their postbuckling response. Whe reas in one of the considered structural models the kinematic continui ty at the contact between the contiguous layers and the free shear tra ction condition on the outer bounding surfaces are solely satisfied, w ithin the second model, in addition to these conditions, also the stat ic interlaminae continuity requirement is fulfilled. Comparisons of th e postbuckling behavior obtained in the context of the two structural models are presented and pertinent conclusions on the implications of the violation of the static continuity requirement are outlined. In or der to study this problem, as a basic pre-requisite, a geometrically n onlinear structural model of initially imperfect laminated shells fulf illing both the static and kinematic interlaminae continuity requireme nts is briefly presented.