  In this work a novel approach is presented for the isogeometric Boundary
Element analysis of domains that contain inclusions with different elastic
properties than the ones used for computing the fundamental solutions. In
addition the inclusion may exhibit inelastic material behavior. In this paper
only plane stress/strain problems are considered.
  In our approach the geometry of the inclusion is described using NURBS basis
functions. The advantage over currently used methods is that no discretization
into cells is required in order to evaluate the arising volume integrals. The
other difference to current approaches is that Kernels of lower singularity are
used in the domain term. The implementation is verified on simple finite and
infinite domain examples with various boundary conditions. Finally a practical
application in geomechanics is presented.
