Beam element for creep analysis for a large displacement regime

In this paper a numerical stability analysis of creeping beam structures is presented. A numerical algorithm using one dimensional spatial beam finite element is developed. Beam members are supposed to be straight and prismatic. Spatial displacements and rotations are allowed to be large but strains are assumed to be small. The corresponding equilibrium equations are formulated in the framework of Eulerian description, using the virtual work principle. Euler-Bernoully beam theory for flexure is assumed as well as Saint-Venant theory for torsion. In contrast to conventional Eulerian formulation, which is linear on element level, in this paper an additional nonlinear part of stiffness matrix is evaluated in order to model Wagner effect.