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Cohesive zone modeling of intergranular cracking in polycrystalline aggregates.
- Source :
-
Nuclear Engineering & Design . Mar2015, Vol. 283, p139-147. 9p. - Publication Year :
- 2015
-
Abstract
- Understanding and controlling early damage initiation and evolution are amongst the most important challenges in nuclear power plants, occurring in ferritic, austenitic steels and nickel based alloys. In this work a meso-scale approach to modeling initiation and evolution of early intergranular cracking is presented. This damage mechanism is present in a number of nuclear power plant components and depends on the material (e.g. composition, heat treatment, microstructure), environment and load. Finite element modeling is used to explicitly model the microstructure – both the grains and the grain boundaries. Spatial Voronoi tessellation is used to obtain the grain topology. In addition, measured topology of a 0.4 mm stainless steel wire is used. Anisotropic elasticity and crystal plasticity are used as constitutive laws for the grains. Grain boundaries are modeled using the cohesive zone approach. Different modeling assumptions/parameters are evaluated against the numerical stability criteria. The biggest positive contribution to numerical stability is the use of cohesive-type contact instead of cohesive elements. A small amount of viscous regularization should be also used along with the addition of a small amount of viscous forces to the global equilibrium equations. Two cases of grain boundary damage initiation are explored: (1) initiation due to normal separation and (2) initiation due to a combination of normal and shear separation. The second criterion significantly decreases the ductility of an aggregate and slightly improves the numerical stability. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 00295493
- Volume :
- 283
- Database :
- Academic Search Index
- Journal :
- Nuclear Engineering & Design
- Publication Type :
- Academic Journal
- Accession number :
- 100795504
- Full Text :
- https://doi.org/10.1016/j.nucengdes.2014.09.041