Abstract: By employing stress optimization condition of hybrid stress element, a quadrangular hybrid stress element HE3 for bending analysis of thick-thin plates is developed based on the energy functional with shear effect and incompatible displacements. The element is free from Shear Locking and Zero Energy Deformation Modes owing to the rational selection of both shear force field and incompatible displacements. Numerical examples show that HE3 element possesses a good performance for thick-thin plates. It is also pointed out by the paper that Spilker's RCI criterion is not sufficient for the absence of the Shear Locking phenomenon in the bending analysis of thick-thin plate elements.

Key words: hybrid stress elements, element optimization condition, incompatible displacements, shear locking, zero energy deformation modes