Postbuckling of laminated composite and sandwich plates and shells: on the significance of the fulfillment of static interlayer continuity conditions

Two structural models of laminatedcomposite and sandwichplates and shells are presented and used to study their postbuckling response. Whereas in one of the considered structural models the kinematiccontinuity at the contact between the contiguous layers and the free shear traction condition on the outer bounding surfaces are solely satisfied, within the second model, in addition to these conditions, also the static interlaminae continuity requirement is fulfilled. Comparisons of the 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 order to study this problem, as a basic pre-requisite, a geometrically nonlinear structural model of initially imperfect laminatedshells fulfilling both the static and kinematic interlaminae continuity requirements is briefly presented.