A mode I crack parallel to the interfaces in a periodically layered medium

摘要

The plane problem of a single crack in aperiodically layered bimaterial composite is considered. For thecase of a long crack loaded by opening normal tractions, theuniversal relation obtained between the Mode I and Mode II stressintensity factors show that the most dangerous crack location liesin the midplane of the layer. This crack location of the Mode Ifinite length crack is examined th detail. A closed formexpression of th Green's function for a single dislocation isderived and the problem is reduced to a singular integral equationof the first kind. The study of the dependence of the normalizedstress intensity factor upon the crack length reveals a wavynonmonotonic behavior. A simple analytic formula for thelimiting case of a semi-infinite crack is derived. It is found to bevalid for a broad rang eof parameters.