Title
A Primal-Dual Finite Element Approximation for a Nonlocal Model in Plasticity
Abstract
We study the numerical approximation of a static infinitesimal plasticity model of kinematic hardening with a nonlocal extension. Here, the free energy to be minimized is a combination of the elastic energy and an additional term depending on the curl of the plastic variable. First, we introduce the stress as dual variable and provide an equivalent primal-dual formulation resulting in a local flow rule. The discretization is based on curl-conforming Nédélec elements. To obtain optimal a priori estimates, the finite element spaces have to satisfy a uniform inf-sup condition. This can be guaranteed by adding locally defined face and element bubbles. Second, the discrete variational inequality system is reformulated as a nonlinear equality. We show that the classical radial return algorithm applied to the mixed inequality formulation is equivalent to a semismooth Newton method for the nonlinear system of equations. Numerical results illustrate the convergence of the applied discretization and the solver.
Year
DOI
Venue
2011
10.1137/100789397
SIAM J. Numerical Analysis
Keywords
Field
DocType
applied discretization,elastic energy,discrete variational inequality system,finite element space,lec element,dual variable,equivalent primal-dual formulation,free energy,element bubble,nonlocal model,primal-dual finite element approximation,mixed inequality formulation,variational inequalities
Discretization,Mathematical optimization,Nonlinear system,Mathematical analysis,Finite element method,Solver,Curl (mathematics),Mathematics,Newton's method,Mixed finite element method,Variational inequality
Journal
Volume
Issue
ISSN
49
2
0036-1429
Citations 
PageRank 
References 
0
0.34
2
Authors
2
Name
Order
Citations
PageRank
C. Wieners191.41
B. Wohlmuth200.34