FRACTURE-MECHANICS OF DISSIMILAR MATERIALS BONDED THROUGH AN ORTHOTROPIC INTERFACIAL ZONE

In this paper the fracture mechanics of orthotropic materials containi ng collinear interface cracks is considered. The primary objective is to study the influence of the thickness and the structure of the inter facial regions on the crack driving force. The interfacial region is a ssumed to be a relatively thin orthotropic elastic layer. The stress i ntensity factors or the strain energy release rates are assumed to be the main measure of the crack driving force. A relatively simple and e fficient method is presented to solve the related elasticity problem. The results are obtained for a wide range of actual material combinati ons. In order to study the influence of the structure of the interfaci al zone, the problem is also solved for isotropic and orthotropic mate rials bonded through a layer with hypothetically selected material pro perties. The results show that the effect of the thickness, the mechan ical properties and the material orientation of the interfacial zone o n the strain energy release rate could be very significant. An interes ting and a rather useful result obtained from the collinear crack solu tions is that the strain energy release rates for multiple cracks in b onded orthotropic materials with or without an interfacial layer may b e predicted by using the results obtained for an isotropic homogeneous plane provided that the normalization factors are selected properly.