Improved displacement based alternative to force based finite element for nonlinear analysis of framed structures

Abstract This paper presents an improved displacement based element (iDBE) for nonlinear finite element analysis of framed structures, which, like the force based elements (FBE), needs neither high order shape functions nor the refinement of the finite element mesh in straight members to attain an accurate solution. To achieve this objective, to the strain fields based on the displacements shape functions of the conventional displacement based element (cDBE) corrective fields are added, which are determined at the element level by the principle of virtual forces. Simple examples involving tapered elements, nonlinear axial-bending interaction and elasto-plastic behavior, are included to illustrate the application of iDBE and compare its performance to cDBE and FBE.