Post-Buckling Behavior of a Circular Rod Constrained Within a Circular Cylinder
An axially loaded weightless circular rod buckles helically when constrained within a circular cylinder. The effects of pinned and fixed-end conditions are investigated. Both end conditions locate the rod end on the cylinder axis, and are found to perturb the helix in an exponentially decaying manner for a distance of less than one helix pitch length. Far from the end, the rod behaves as an undisturbed constant-pitch helix. The distance from the rod end to the point of initial contact with the cylinder wall is calculated. Closed-form analytical solutions are obtained for the deflected shapes and internal reactions of the end sections. The solution procedure applies to rods of either finite or infinite length.