It was recalled that Eshelby had shown that a glide dislocation could move, without radiating energy, at up to v2 times the shear-wave speed. The same velocity played a special role in shear-crack propagation. This link had not attracted much attention due to a lack of experiments and numerical simulations concerning transonic defects. An attempt was made to provide a unified treatment of transonic cracks and dislocations by building on Eshelby’s work. Stroh's method was used here to generalize the Eshelby theorem to orthotropic and anisotropic elastic solids. In the case of orthotropic solids, proof of existence of the radiation-free speed was provided. In the case of general anisotropic solids, there were 3 wave speeds c3 < c2 < c1 to be considered for any given crystal orientation. In the first transonic regime, c3 < v < c2, there always existed a radiation-free state for any given velocity of a moving defect. In the second transonic regime, c2 < v < c1, the existence of radiation-free states appeared to depend upon both the symmetry properties of the material and the defect orientation. Examples of the second transonic regime included a crack propagating in an isotropic solid, and a crack propagating along a plane of symmetry in an orthotropic solid.

On Radiation-Free Transonic Motion of Cracks and Dislocations. H.Gao, Y.Huang, P.Gumbsch, A.J.Rosakis: Journal of the Mechanics and Physics of Solids, 1999, 47[9], 1941-61