Linear bifurcation of perfect column-supported cylinders: Support modelling and boundary conditions

Abstract

Large elevated silos and tanks are generally supported on a number of columns. The discrete supports of the columns give rise to high stresses adjacent to the column terminations. In particular, very high meridional compressive stresses arise above each column termination and these can lead to buckling of the shell at a load much lower than that for a uniformly supported shell. This paper presents a study of the linear bifurcation buckling behaviour of column-supported thin elastic perfect cylinders using the finite element method. Cylinders on both rigid and flexible column supports are studied, and the effects of varying several shell parameters are examined. The effects of the top and bottom edge boundary conditions are also investigated. It is well recognised that the linear bifurcation load is only an upper bound on the actual elastic buckling load, because the effects of large deflections and initial imperfections are ignored. Nevertheless, our understanding of the buckling behaviour of these structures is so limited that the results obtained here provide a significant starting point from which more elaborate studies may follow.