Abstract
In the FEM formulation of a plane beam element, the interpolation is improved toward consistency with the beam-column theory. The geometrical effects of the flexural and axial displacements upon the longitudinal strain are explicitly analyzed in up to their second-order terms. The flexural displacement is framed, as usual, in the cubic-polynomoal distributions, the magnitudes of which are linear with the nodal parameters. But, in the interpolation of the axial displacement, the secondary effects of the flexural displacement are taken into account, which are expressed in a quadratic form of the deflection parameters.
