Three-dimensional dynamic steady state growth of a semi-infinite plane crack in a
transversely isotropic solid is considered. Growth takes place on a principal plane with the
material symmetry axis as one tangent. Fracture is brittle, and driven by compressive
loads that translate on the crack surfaces. Translation speed is constant and subcritical,
but direction with respect to the principal axes is arbitrary. An analytical solution
is obtained, and examined in light of the dynamic energy release rate criterion for the
case of a translating compressive point force. Introduction of quasipolar coordinates
leads to a nonlinear first-order differential equation for the distance between force
and crack edge. The equation depicts a crack edge that tends to the rectilinear away
from the force. An analytical expression for the distance measured parallel to translation
direction indicates a marked deviation from the rectilinear near the point force.
