An exact solution of the antiplane problem of the diffraction of a plane el
astic SH-wave with a step profile by a wedge is obtained. The stresses on t
he wedge sides are assumed to be proportional to a linear combination of th
e displacements, velocities and higher derivatives with respect to time of
the displacements along the wedge axis. A solution of the problem is obtain
ed using integral transformations with subsequent transformation using Cagn
iard's method. Solutions of the corresponding problems with boundary condit
ions of the Winkler and inertial types are considered. When a wave with a l
inear profile is incident on the wedge the stresses suffer a discontinuity
of the second kind on the diffraction wave front; the same type of feature
is observed in the problem with the inertial condition. (C) 1999 Elsevier S
cience Ltd. All rights reserved.