A BDDC Algorithm for Mortar Discretization of Elasticity Problems

Abstract. A BDDC (balancing domain decomposition by constraints) algorithm is developed for elasticity problems in three dimensions with mortar discretization on geometrically nonconforming subdomain partitions. Coarse basis functions in the BDDC algorithm are constructed from primal constraints on faces. These constrains are similar to the average matching condition and the moment matching condition on common faces or edges considered in [10, 7]. A condition number bound is proved to be C(1+log(H/h))3 for geometrically non-conforming partitions as well as to be C(1 + log(H/h))2 for geometrically conforming partitions.