Bifurcation creep buckling of viscoelastic laminated circular cylindrical shells

The prebuckling creep deformation and bifurcation creepbuckling for viscoelastic symmetrically laminated circular cylindricalshells subjected to axial compression are analyzed. Boltzmann hereditaryconstitutive relationship is used to model the viscoelastic behavior oflamina and the instantaneous elastic response is assumed whenbifurcation occurs. The governing equations of prebuckling creep deformationand bifurcation buckling are based on DMV shallow shell theory and the K\'arm\'an-Donnell geometrically nonlinear relationship. Thenumerical procedure and analytical deduction based on viscoelasticapproachand quasi-elastic approach, respectively, are performed to investigate thebehavior of prebuckling creep deformation. A semi-analytical solutionstrategy is adopted to obtain the critical time of bifurcation buckling.Particular attention is placed on the analysis of glass/epoxy matrixcomposite circular cylindrical shells, results of prebuckling creepdeformation show that the time-dependent evolution of flexural deformationand circumferential membrane force is strongly dependent on the lay-upconfiguration of cylindrical shells. Both of them decrease in the case ofcross-ply conditions and increase for symmetric angle lay-up mode withtime. Theboundary condition at two ends of short laminated cylindrical shells withsymmetric angle lay-up plays a key role on the stability and the bifurcationcreep buckling may not be observed for simply supported ends.The increase of the ratio of radius to thickness will deteriorate the longterm stability of laminated cylindrical shells with constrained ends.