Note on the instability of tubes subjected to end pressure, and on the folds in a flexible material

Abstract

When a straight rod is subjected to end compression it is stable for small lateral displacements unless the compressing force exceeds a definite limit depending on the elastic constants of the material of the rod and its length and cross section dimensions. If this limit is exceeded, the rod is unstable and the least departure from straightness grows under the action of the force, the axis of the rod then taking the form of one of the well-known elastic curves; and this is the only form which a solid rod can take in the circumstances.