The Elasto-Plastic Analysis of Imperfect Cylinders.

Abstract

A finite difference formulation is presented for the large deflexion elasto-plastic analysis of initially imperfect thin cylinders subjected to axial compression and external pressure. The elasto-plastic rigidities of the shell are calculated using a rigorous multi-layer approach, and the governing equations are solved in an incremental form using dynamic relaxation. Complete load-deflexion curves (which include response after the attainment of peak load) have been obtained for various loadings and shell geometries. Although the Paper covers a number of aspects of cylinder behaviour, it focuses attention on the variations in strength encountered in many experimental investigations. Notation D mean cylinder diameter E Young's modulus I unstiffened cylinder length (ring stiffener spacing) R mean cylinder radius t cylinder thickness W out of plane displacement w o peak geometric initial imperfection magnitude c average longitudinal strain eo yield strain U average longitudinal stress uo yield stress

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