A NEW METHOD OF QUADRILATERAL ELEMENTS BY AREA COORDINATES INTERPOLATION

A universal technique for developing new plane quadrilateral spline elements is proposed. In this approach, the triangular area coordinate interpolation and the B-net method are employed to establish the formulations, which satisfy the conforming conditions between two adjacent elements. By using 1-, 2- and 3-order bivariate spline interpolation bases, three new 4-, 8- and 12-node quadrilateral elements are successfully constructed, respectively. The displacement interpolation functions of the new 8- and 12-node elements possess higher order completeness than the corresponding isoparametric quadrilateral elements and the generalized conforming elements by area coordinates, and the resulting stresses are continuous within an element. Some appropriate examples are employed to evaluate the performance of the proposed elements. The numerical results show that the new spline elements present higher precision and are insensitive to mesh distortions.