Postbuckling Behavior of Open Cylindrical Shells

Postbuckling behavior of perfect open cylindrical shells with free longitudinal edges and simply supported ends subjected to uniform axial compression is studied. Field equations based on the large deflection theory are reduced to a set of nonlinear finite difference equations. With Poisson's ratio μ = 0, the axial loading condition results in a linear eigenvalue problem when the deflection is infinitesimally small. A computer technique for tracing the equilibrium paths, using the eigen-vectors as starting directions and the Newton-Raphson method for solving the nonlinear equations, is presented. Examples show several interesting features of the equilibrium paths and deflection patterns. The linear buckling load is the upper limit of the buckling load as it is the starting point of an unstable equilibrium path. Despite the coarse nets used, both the critical load and the modes of buckling were found to agree with those obtained by the analytical solution of the linear theory. However, due to the coarseness, the local buckling load for the shearing stress equal to zero end conditions was not determined.