Refined hybrid method for plane isoparametric element using an orthogonal approach

Abstract

In this paper a refined hybrid method based on a new variational formulation and orthogonal approach is developed for plane isoparametric elements. According to this formulation plane refined hybrid elements RGH4 (four-noded model) and RGH8 (eight-noded model), which are typical low- and high-order models, respectively, have been proposed. The element stiffness matrix of the present element can be decomposed into a series of matrices with respect to assumed strain modes and can be derived explicitly or by using lower-order numerical integration. It is shown that the present method is more rational than generalized hybrid methods and hybrid stress method for improving the computational efficiency. A number of numerical examples are used to demonstrate the effectiveness of the proposed elements in terms of convergence, accuracy, sensitivity of distorted mesh and free of locking. © 1992.