AN AXISYMMETRICAL CRACK IN BONDED MATERIALS WITH A NONHOMOGENEOUS INTERFACIAL ZONE UNDER TORSION

In this study the mode III axisymmetric crack problem for two dissimil ar homogeneous materials bonded through a thin layer of nonhomogeneous interfacial region is considered. The shear modulus of the interfacia l layer is assumed to be mu(2)(z) = mu(1) exp (alpha z). If is also as sumed that mu(3) = mu(1) exp (alpha h), h being the thickness of the l ayer and mu(1) and mu(3) the shear moduli of the adherents. The main r esults of the study are the stress intensity factors, the strain energ y release rates and to a limited extent, the crack-opening displacemen ts obtained as functions of the two primary variables h/a and mu(3)/mu (1) under various lending conditions, where a is the radius of the cra ck. Some results are also presented for a penny-shaped crack in an unb ounded nonhomogeneous medium.