EIGHT-NODE QUADRILATERAL MEMBRANE ELEMENT FORMULATED BY MIXED USE OF THE THREE TYPES OF THE QUADRILATERAL AREA COORDINATE METHOD

Three types of the quadrilateral area coordinate method have been proposed. If these three types are used mixedly, the optimal model of quadrilateral element will then be obtained. In this paper, these three types of the quadrilateral area coordinate method are mixedly used to develop one eight-node quadrilateral membrane element. The new element exhibits the following advantages: i) the new element possesses distinguished performance and is insensitive to mesh distortion. In contrast, the eight-node isoparametric element Q8 is very sensitive to mesh distortion. This advantage reflects the common characteristics of the three types (Ⅰ, Ⅱ, Ⅲ) of the quadrilateral area coordinate method. ii) The formulation procedure and the expression of the shape function matrix of the new element are very simple. This advantage is due to the ingenious and optimal combination of the three types (Ⅰ, Ⅱ, Ⅲ) of the quadrilateral area coordinate method.