A study on an effect of geometric singularities on ductile fracture

This paper describes the appearance of fractures in the vicinity of geometric singularities in cold upsetting of three series of slightly different samples between flat and spherical dies. The main goal of the research is to understand an effect of geometric singularities on ductile fracture. To this end, the series of tests are designed such that the site of fracture initiation moves to the geometric singularity, as compared to conventional tests, independently of its effect on the ductile fracture process. The paper concerns with a qualitative effect of geometric singularities on ductile fracture initiation rather than with quantitative values of parameters controlling the ductile fracture process.