Bifurcation of Elastoplastic Pressure-Sensitive Hollow Cylinders

Abstract

A linear bifurcation analysis is presented for pressure sensitive elastoplastic hollow cylinders under radial surface loads. Material response is modeled by flow and deformation theories of the Drucker-Prager solid accounting for arbitrary hardening. Sample calculations are given for cylinders that deform in axially symmetric patterns under uniform radial pressure applied at the boundaries. No bifurcation points were found with flow theory in the realistic range of stress though the primary equilibrium path is nearly identical for both theories. For thick-walled cylinders the dominant bifurcation mode predicted by deformation theory appears to be a circumferential surface instability. Deformation theory results for bifurcations are apparently not sensitive to deviations from associativity.