On the general treatment of a cracked multi-layered medium in antiplane viscoelasticity

An arbitrary crack lying in a viscoelastic multi-layered medium under an anti-plane concentrated load is discussed in this paper. The fundamental elastic solution is obtained as a rapidly convergent series in terms of complex potentials via successive iterations of the Mobius transformation in order to satisfy continuous conditions on multiple different interfaces. Based on the correspondence principle, the Laplace transformed viscoelastic solution is then directly determined from the corresponding elastic one. Using the singular integral technique, the time-dependent mode-III stress intensity factor of the crack tip can be solved numerically in a straightforward manner. Finally, some typical examples showing the effect of bonded layers and crack orientations on the stress intensity factor are also discussed. The results show that the stress intensity factor decreases monotonically with time if the bonded layer is stiffer than the cracked layer. (C) 2002 Elsevier Science Ltd. All rights reserved.