Chang-Ock Lee

A locking-free nonconforming finite element method for planar linear elasticity

We propose a locking-free nonconforming finite element method based on quadrilaterals to solve for the displacement variable in the pure displacement boundary value problem of planar linear elasticity. The method proposed in this paper is optimal and robust in the sense that the convergence estimates in the energy and L2-norms are independent of the Lamé parameter λ.

A Preconditioner for the FETI-DP Formulation with Mortar Methods in Two Dimensions

In this paper, we consider a dual-primal FETI (FETI-DP) method for elliptic problems on nonmatching grids. The FETI-DP method is a domain decomposition method that uses Lagrange multipliers to match solutions continuously across subdomain boundaries in the sense of dual-primal variables. We use the mortar matching condition as the continuity constraints for the FETI-DP formulation. We construct a preconditioner for the FETI-DP operator and show that the condition number of the preconditioned FETI-DP operator is bounded by

B_z

C \max_{i=1,\ldots,N} \{ \left(1+\log\left( H_i / h_i \right)\right)^2 \},

A FETI-DP Formulation for the Stokes Problem without Primal Pressure Components

where

An algorithm for stylus instruments to measure aspheric surfaces

H_i

First-Order System Least Squares For Linear Elasticity: Numerical Results

and

Ramp-Preserving Denoising for Conductivity Image Reconstruction in Magnetic Resonance Electrical Impedance Tomography

h_i

A Nonlinear Structure Tensor with the Diffusivity Matrix Composed of the Image Gradient

are sizes of domain and mesh for each subdomain, respectively, and