Static and dynamic instability analysis of composite cylindrical shell panels subjected to partial edge loading

The postbuckling and dynamic instability behavior of simply supported composite cylindrical shell panels subjected to dynamic partial edge loadings and transverse patch loadings is studied in this paper considering von Kármán type of non-linearity. The stress distribution within the panel due to the applied partial edge loadings is evaluated by panel׳s membrane analysis. Subsequently using these stress distribution and via Hamilton׳s variational principle, the equations governing the instability behavior of shell panel are derived. Neglecting inertia terms, governing equations for the postbuckling analysis of panel are obtained. Galerkin׳s method is used in the solution procedure. It is observed from the postbuckling analysis that the cylindrical shell panel subjected to partial edge compression behaves as an imperfect shell panel as the partial edge compression in the x-direction induces tensile stress in the y-direction which makes the shell panel to deflect out-of-plane. It is also observed that by suitably adjusting the lamina number and lamina layup, the snap through behavior of shells can be altogether avoided. Dynamic instability regions of simply supported composite shell panels are traced by the method suggested by Bolotin. The linear and non-linear dynamic responses of the shell in stable and unstable regions are studied. This brings out various features of the instability problem such as, existence of beats and its dependence on forcing frequency and initial conditions, and effect of non-linearity on the response. It is found that for certain value of dynamic partial edge loading, the panel exhibits chaotic behavior.