Mode III near and far fields for a crack lying in or along a joint

Matched asymptotic expansions allow one to give, at two scales, a descripti on of the solution to the antiplane problem of two different elastic substr ates bonded together by a thin elastic adhesive layer with a crack lying in side or even outside at a short distance of it. The leading term is the cla ssical solution obtained, by finite elements for instance, when perfect tra nsmission conditions are assumed through the line modelling the interface. The corrections depend on the relative stiffnesses of the components and on the thickness of the joint. It also depends on the crack location, within the joint or outside. Two kinds of Mode III stress intensity factors are de fined, a fictitious and an actual one, they are so-called far and near (or remote and local) by the authors. The fictitious one is meaningless and mus t be rescaled by an appropriate coefficient to give the actual one. (C) 200 0 Elsevier Science Ltd. All rights reserved.