  The present work deals with the problem of a semi-infinite crack steadily
propagating in an elastic body subject to plane-strain shear loading. It is
assumed that the mechanical response of the body is governed by the theory of
couple-stress elasticity including also micro-rotational inertial effects. This
theory introduces characteristic material lengths in order to describe the
pertinent scale effects that emerge from the underlying microstructure and has
proved to be very effective for modeling complex microstructured materials. It
is assumed that the crack propagates at a constant sub-Rayleigh speed. An exact
full field solution is then obtained based on integral transforms and the
Wiener-Hopf technique. Numerical results are presented illustrating the
dependence of the stress intensity factor and the energy release rate upon the
propagation velocity and the characteristic material lengths in couple-stress
elasticity. The present analysis confirms and extends previous results within
the context of couple-stress elasticity concerning stationary cracks by
including inertial and micro-inertial effects.
