Improved Two-Dimensional Finite Element

Plane elements based on assumed displacement fields are reviewed. A plane element based on the assumed-stress hybrid principle is found to model bending action as well as any of the displacement-based elements. Contrary to many displacement-based elements, the hybrid is valid for arbitrary quadrilateral shape. A modification is introduced to remove the orientation-dependence of the element and improve its stress prediction. The element formulation is detailed so that it may be easily adopted by interested users. Numerical examples suggest that among plane quadrilaterals having four nodes and eight degrees-of-freedom, the modified hybrid is the most effective element currently available.