A Modified Nonconforming 5-Node Quadrilateral Transition Finite Element

This paper analyzes a nonconforming 5-node quadrilateral transition finite element for Poisson equation.This element was originally proposed by Choi and Park[Computers and Structures,32(1989),pp.295–304 and Thin-Walled Structures,28(1997),pp.1–20]for the analysis of Mindlin plates.We show the consistency error of this element is only O(h^(1/2))over the transition edges of the quadrilateral subdivision.By modifying the shape functions with respect to mid-nodes,we get an improved version of the element for which the consistency error is O(h).Numerical examples are provided to verify the theoretical results.