Local Collapse of Axially Compressed Pressurized Thin Steel Cylinders

Cylindrical bins, silos, and tanks are thin shell structures subject to internal pressure from stored materials together with axial compression from the frictional drag of stored materials on the walls and roof loads. The governing failure mode is frequently buckling under axial compression. The internal pressure can significantly enhance the buckling strength, but high internal pressures lead to severe local bending near the base. Local yielding then precipitates a buckling failure. This failure mode, often known as “elephant's foot” buckling, has received very little attention to date and is commonly ignored in tank and silo design. This paper describes the results of a study of the elastic‐plastic instability and collapse of axially loaded internally pressurized perfect thin cylindrical shells adjacent to the support. The results are compared with previous design recommendations and a new simple equation is proposed for use in design.