CRACK TIP SHARPNESS EFFECTS IN FRACTURE AND MACHINING

摘要

Recent studies have proposed measuring fracture toughness using machining tests [1,2,3]. These can be convenient, particularly for softer materials where plastic deformation can lead to crack tip blunting. A sharp tool is used (tip radius 5 urn) and the Gc value determined was compared with that obtained from standard LEFM or Jc tests. The agreement was quite good [3] but the standard test results were usually somewhat higher. Here we offer some suggestions about the reasons for this effect.