We prove convergence and optimal complexity of an adaptive finite element algorithm on quadrilateral meshes. The local mesh refinement algorithm is based on regular subdivision of marked cells, leading to meshes with hanging nodes. In order to avoid multiple layers of these, a simple rule is defined, which leads to additional refinement. We prove an estimate for the complexity of this refinemen...

In this paper we investigate the relationship between stabilized and enriched finite element formulations for the Stokes problem. We also present a new stabilized mixed formulation for which the stability parameter is derived purely by the method of weighted residuals. This new formulation allows equal order interpolation for the velocity and pressure fields. Finally, we show by counterexample ...

where f ∈ L2(Ω). Let Th be a simplicial or convex quadrilateral triangulation of Ω. In C 0 interior penalty methods, we choose the discrete space Vh ⊂ H 1 0 (Ω) to be either a P` (` ≥ 2) triangular Lagrange finite element space or a Q` (` ≥ 2) tensor product finite element space associated with Th. By an integration by parts argument [4], it can be shown that the solution u of (1), which belong...

We present techniques of a posteriori error estimation for Q1 finite element discretizations based on residual evaluations with respect to test functions of higher-order. This technique is designed for quadrilateral (or hexahedral) triangulations and gives local error indicators in terms of nodal contributions. We show reliability and efficiency of the estimator. Moreover, we present a simplifi...

The coordinate transformation for quadrilateral isoparametric elements is well-defined in the finite element literature. However, a corresponding inverse transformation is not found. In fact, it has been commonly believed that no explicit solutions to the inverse transformation problem exist. This paper shows that if geometric considerations are used, a complete set of general solutions to the ...

Abstract. A hybrid stress finite volume method is proposed for linear elasticity equations. In this new method, a finite volume formulation is used for the equilibrium equation, and a hybrid stress quadrilateral finite element discretization, with continuous piecewise isoparametric bilinear displacement interpolation and two types of stress approximation modes, is used for the constitutive equa...

A higher order hybrid finite element – method of moments (FEM-MoM) technique for threedimensional analysis and design of radiating and scattering structures is presented. The technique uses generalized parametric hexahedral and quadrilateral elements of arbitrary geometrical orders in conjunction with curland divergence-conforming hierarchical polynomial vector basis functions of arbitrary appr...