A KINEMATICALLY EXACT FINITE-ELEMENT FORMULATION OF ELASTIC-PLASTIC CURVED BEAMS

A finite element, large displacement formulation of static elastic-pla stic analysis of slender arbitrarily curved planar beams is presented. Non-conservative and dynamic loads are sit present not included. The Bernoulli hypothesis of plane cross-sections is assumed and the effect of hear strains is neglected. Exact non-linear kinematic equations of curved beams, derived by Reissner are incorporated into;a generalized principle of virtual work through Lagrangian multipliers. The only fu nction that has to be interpolated in the finite element implementatio n is the rotation of the centroid axis of a beam. This is an important advantage over other classical displacement approaches since the fiel d consistency problem and related locking phenomena do not arise. Nume rical examples, comprising elastic and elastic-plastic, curved and str aight beams, at large displacements and rotations, show very nice comp utational and accuracy characteristics of the present family of finite elements. The comparisons with other published results very clearly s how the superior performance of the present elements. (C) 1998 Elsevie r Science Ltd. All rights reserved.