Buckling and post-buckling behavior of a pipe subjected to internal pressure

It is well known that a thin elastic shell under external pressure may undergo buckling and collapse. Less well known is that a hollow beam under internal pressure may buckle as an Euler column. This is the subject of the present study. The buckled deflection and natural frequency about the buckled configuration. of a vertical pipe with clamped (y-axis) and hinged (z-axis) boundary conditions at the lower support location, considering the influence of internal pressure and initial (manufactured) curvature, has been studied analytically and experimentally, The buckling and postbuckling behavior of the pipe beam with an initial static deflection depends upon the nonlinear coupling due to deflection in the two directions including the anisotropic boundary condition at the one support location. The coupling effects increase as the internal pressure and the initial static deflection increase. When the initial static deflection is zero, the coupling effect disappears. The theoretical results agree reasonably well with the experiments.