A Nitsche extended finite element method for incompressible elasticity with discontinuous modulus of elasticity

R. Becker (1, 2) , Erik Burman (3, 4) , Peter Hansbo (5)

1 CONCHA - Complex Flow Simulation Codes based on High-order and Adaptive methods
2 LMAP - Laboratoire de Mathématiques et de leurs Applications [Pau]
3 IACS - CMCS - Institut d'Analyse et Calcul Scientifique [Lausanne]
4 Department of Mathematics [Sussex]
5 Chalmers University of Technology [Göteborg]

In this note we propose a finite element method for incompressible (or compressible) elasticity problems with discontinuous modulus of elasticity (or, if compressible, Poisson's ratio). The problem is written on mixed form using P1–continuous displacements and the space of piecewise P0 pressures, leading to the possibility of eliminating the pressure beforehand in the compressible case. In the incompressible case, the method is augmented by a stabilization term, penalizing the pressure jumps. We show a priori error estimates under certain regularity hypothesis. In particular we prove that if the exact solution is sufficiently smooth in each subdomain then the convergence order is optimal.

Domaines: Analyse numérique [math.NA]

R. Becker, Erik Burman, Peter Hansbo. A Nitsche extended finite element method for incompressible elasticity with discontinuous modulus of elasticity. [Research Report] 2008. ⟨inria-00341737⟩