  An adapted deflation preconditioner is employed to accelerate the solution of
linear systems resulting from the discretization of fracture mechanics problems
with well-conditioned extended/generalized finite elements. The deflation space
typically used for linear elasticity problems is enriched with additional
vectors, accounting for the enrichment functions used, thus effectively
removing low frequency components of the error. To further improve performance,
deflation is combined, in a multiplicative way, with a block-Jacobi
preconditioner, which removes high frequency components of the error as well as
linear dependencies introduced by enrichment. The resulting scheme is tested on
a series of non-planar crack propagation problems and compared to alternative
linear solvers in terms of performance.
