CONSTRUCTION OF QUADRILATERAL MEMBRANE ELEMENTS WITH DRILLING DOF USING AREA COORDINATE METHOD

Two generalized conforming quadrilateral membrane elements with drilling degree-of-freedom named AQ4è and AQ4èλ are developed. In the formulation, the quadrilateral area coordinates are used instead of the isoparametric coordinates. Both elements pass the strict patch test and their convergence is assured. Numerical examples show that the proposed elements exhibit better efficiency and accuracy than other elements. Both elements are insensitive to mesh distortion and lock-free for the MacNeal test problem of trapezoidal locking.