Fracture criteria in cracked bimaterial elastic plates

A plane bimaterial model is introduced which allows the determination of the stress intensity factors K sub(I) and K sub(I) sub(I), as well as the fracture angle theta sub(0). The model is composed of a long orthogonal strip penetrating into an elastic orthogonal soft matrix. The strip is cemented along three of its edges with the matrix and the composite is submitted to either symmetric tension, or compression. Simple tension of the model creates slowly progressing cracks in the matrix parallel to the transverse edge of the strip, whereas compression develops slowly growing oblique cracks at different angles to the transverse edge of the strip. For the evaluation of the components of the complex stress intensity factor, the optical method of reflected caustics is used. The orientation of both external and internal caustics yield also the fracture angle theta sub(0).