Some computational results for robust FETI-DP methods applied to heterogeneous elasticity problems in 3D

Robust FETI-DP methods for heterogeneous, linear elasticity problems in three dimensions were developed and analyzed in Klawonn and Widlund [2004]. For homogeneous problems or materials with only small jumps in the Young moduli, the primal constraints can be chosen as edge averages of the displacement components over well selected edges; see Klawonn and Widlund [2004] and for numerical experimental work, Klawonn and Rheinbach [2005a]. In the case of large jumps in the material coefficients, first order moments were introduced as additional primal constraints in Klawonn and Widlund [2004], in order to obtain a robust condition number bound. In the present article, we provide some first numerical results which confirm the theoretical findings in Klawonn and Widlund [2004] and show that in some cases, first order moments are necessary to obtain a good convergence rate.