Shear dominated transonic interfacial crack growth in a bimaterial I-II. Asymptotic fields and favorable velocity regimes

Motivated by experimental observations of transonic crack tip speeds (Lambros and Rosakis, 1994c, J. Mech. Phys. Solids 43(2), 169–188), the problem of intersonic interfacial crack growth in an elastic-rigid bimaterial system is analysed. Following the analytical procedure employed in Liu et al. (1993, J. Mech. Phys. Solids 41, 1887–1954), the two-dimensional in-plane asymptotic deformation field surrounding the tip of a crack propagating intersonically along an elastic-rigid bimaterial interface, is obtained. The theoretical results show that the near-tip stress field does not exhibit oscillations, while a stress singularity weaker than 0.5 still exists and is a function of the crack tip speed. In addition, due to the intersonic nature of crack growth, a singular line emanating from the moving crack tip is present in the near-tip field. Across this line, stresses and particle velocities suffer infinite jumps. The theoretical analysis also shows that the near-tip deformation field is shear dominated. It is also shown that in the velocity range cs < v < √2cs, either crack face contact or negative normal tractions ahead of the crack tip exist. Visual evidence of such contact is reported in Part I of this study. These observations, together with additional experimental results of Part I, lead to the conclusion that crack growth is favorable in the velocity regimes 0 < v < cs and √2cs < v < c1.