Numerical Simulation Analysis Of Mechanical Field At Tip Of Intergranular Crack

Because of the complexity of needing to carry rot candle, high temperature, high pressure,according to the neutron blessing, fatigue loads and shock loads and thermal stress joint action,welded joints of safety end of PWR nuclear components are often the key parts of the occurrenceof failure. SCC, fatigue cracking, manufacturing defects are common factors that cause a varietyof defects. For intergranular corrosion cracking, SCC of welded joints of safety end of PWRnuclear components are extended along the grain. Intergranular fracture is one kind of its manyfailure forms. Research on the intergranular fracture morphology and fracture mechanism is stilldeepening. In order to analysis of the influence of different parameters on characterization ofthe intergranular crack tip field, to research the action and effect of different factors onintergranular crack, to further deepen the knowledge and understanding of intergranular cracktip field, the crack tip field of intergranular crack was simulated and analyzed in this dissertationbased on finite element software ABAQUS. The main contents are as follows:(1)Making a distinction between grain and grain boundary material, determining thematerial and geometry used for the analysis model, the global macro model of standard compacttension specimen and micro sub-model of grains and grain boundary microstructure wereconstructed by finite element software ABAQUS using triangulation method;(2)On the macroscopic scale, in order to observe the impact of mechanics and materialfactors on the boundary conditions of sub-model passed from global model by using variableparameter method, a global intergranular cracks computing model was established;(3)On the meso scale, in order to get the impact of geometric factors on the crack tip field,FEA model of different grain size were established；(4)On the meso scale, in order to get the impact of crack length on the crack tip field, FEAmodel of different crack length were established； 5.In addition, the impact with the boundary conditions（mechanical factors and materialfactors） of meso scopic model transformed from the global model on crack tip field wasspecific analysis in this paper.