Near-tip fields for transient crack growth in a material whose constit
utive behavior is represented by the Bodner-Partom model are investiga
ted for the case of plane strain mode I fracture under small-scale yie
lding conditions. At time t = 0, a load is applied to the cracked body
. At the same instant, the crack starts to propagate with a constant v
elocity. A boundary integral equation method is used to compute the co
mplete fields of stress and deformation. An expression for the near-ti
p time-dependent stress intensity factor has been derived and numerica
l results are presented for several crack tip speeds. Evolution of the
stresses as the crack extends quasi-statically into the viscoplastic
solid is also presented.