Welded Joint Impact And Fracture Toughness

Operational security and reliability are very important for engineering structures, such as explosive vessel, which are worked under dynamic impact loading. It is badly affected by the dynamic fracture toughness of welded joints in the structure.The paper introduces briefly the characteristic of welded joints, the testing methods of dynamic fracture toughness. More attentions are paid to the investigation of welded joint' impact toughness and dynamic fracture toughness under dynamic impact loading. In doing so, a measuring system of impact toughness with high loading rate was established by combined the pressure gas gun of split Hopkinson Pressure Bar with the measuring technology of the three-point bending speciments. Analysis of testing dates shows that welded joints' impact toughness and dynamic fracture toughness are affected by matching, zone, loading rate and temperature. The crack tip stress field and strain field of welded joints under dynamic loading are described. The dimension of plastic zone around crack tip of welded joints under dynamic loading is very small, which indicates that the rupture of crack is brittleness. On the basis of analysis above-mentioned, instructive advice on design of the structure under dynamic impact loading are proposed.