Self-similar problem of a penny-shaped crack subjected to pure torsion

The solution of a penny-shaped crack in an infinite body subjected to pure torsion is carried out. It is assumed that at time t ⩾ 0, a penny-shaped flaw begins to propagate uniformly along the surface y = 0 with a constant speed s which is smaller than the SH-wave speed. This penny-shaped crack is twisted about the y -axis by a constant torque acting at y = ± ∞ of the body. By using the method of the rotational superposition in conjunction with the Smirnov-Sobolev method of self-similar potentials for the two-dimensional problems, the solution of this problem is obtained. The dynamic stress intensity factor and the crack tearing displacement are also evaluated.