SINGULARITIES AT THE TIP OF A CRACK TERMINATING NORMALLY AT AN INTERFACE BETWEEN 2 ORTHOTROPIC MEDIA

The order of stress singularities at the lip of a crack terminating no rmally at an interface between two orthotropic media is analyzed. Char acteristic equation in complex form for the power of singularity s, wh ere 0 < Re{S} < 1, is first set up for two general anisotropic materia ls. Attention is then focused on the problem that is composed by two o rthotropic media where one of them them (say material #2) the material principal axes are aligned while the other one (say, material #1) the principal axes can have an angle gamma relative to the interface. For such a problem, a real form of the characteristic equation is obtaine d. The roots arefunctions of gamma in general. Two real roots exist fo r most values of gamma; however, there are possible ranges of gamma th at the complex roofs will occur. The roots s are found to be independe nt of gamma when material #1 has the property that delta((1)) = 1. Whe n gamma = 0, two roots are always real. Furthermore, each of these two roots is associated with symmetric or antisymmetric mode and they bec ome equal when Delta = 1. Many other features of the effects of the ma terial parameters on the behaviors of the roots s are further investig ated in the present work, where the six generalized Dundurs' constants , expressed in terms of Krenk's parameters, play an important role in the analysis.