Theory and numerics of three-dimensional beams with elastoplastic materialbehaviour

A theory of space curved beams with arbitrary cross-sections and an associa ted finite element formulation is presented. Within the present beam theory the reference point, the centroid, the centre of shear and the loading poi nt are arbitrary points of the cross-section. The beam strains are based on a kinematic assumption where torsion-warping deformation is included. Each node of the derived finite element possesses seven degrees of freedom. The update of the rotational parameters at the finite element nodes is achieve d in an additive way. Applying the isoparametric concept the kinematic quan tities are approximated using Lagrangian interpolation functions. Since the reference curve lies arbitrarily with respect to the centroid the develope d element can be used to discretize eccentric stiffener of shells. Due to t he implemented constitutive equations for elastoplastic material behaviour the element can be used to evaluate the load-carrying capacity of beam stru ctures. Copyright (C) 2000 John Wiley & Sons, Ltd.