Commonly, the flat shell element which consists a membrane element with 2 degrees of freedom and a plate element with 3 degrees of freedom has great problems because of the only missing one - drilling degree of freedom. In case of sharing one node by two or more elements in a plane, some singular problems are occurred because there are no stiffness of drilling part.
In this paper, a triangular element with drilling degree of freedom is presented. And this element is developed by combined 2 nodes of quadrilateral element. To improve the efficiency, the program code of quadrilateral element is used. Non-conforming mode and a direct modification method are applied for better behavior of developed element. The element passes in the patch test, doesn't show spurious zero energy mode.
Finally, Numerical examples are presented to show the performance of membrane element developed in this study
