A refined nonconforming plane quadrilateral element

A refined nonconforming plane quadrilateral element RQ6 based on the refined nonconforming element method has been developed directly in Cartesian coordinates. The formulation of RQ6 element is very simple, and the element can pass the patch test. Several numerical examples, including static and vibration problems, are analyzed using the new element, and the computed results have proved that the accuracy of the RQ6 element is quite high.