STATISTICAL CHARACTER OF THE FAILURE OF MULTIPHASE MATERIALS DUE TO HIGH-PRESSURE WATER-JET IMPINGEMENT

In this study, fracture experiments on multiphase material samples hav e been carried out using high speed water jets. Based on fracture geom etry measurements and on grain analyses it was found that the fracture of this type of materials by water jet impingement is a highly locali zed process at low pressure ranges. Beyond a critical pressure range o f about 30 times the material's tensile strength a change in the mater ial behaviour was observed. This result is in agreement with a theory suggested by Powell and Simpson. To explain the local character of the failure process, a simplified fracture model is introduced which resu lted in a relation between a fracture probability parameter and the fr acture width in the damaged materials.