Fracture Capabilities in Grizzly with the extended Finite Element Method (X-FEM)

Modular system for probabilistic fracture mechanics analysis of embrittled reactor pressure vessels in the Grizzly code

“…Because it is based on a finite element framework, Grizzly also provides the ability to directly solve for the stress fields around a flaw using a detailed 2D or 3D finite element model. The flaw geometry can be represented either by incorporating it in the mesh topology [28], or using the extended finite element method (XFEM) [29,30] to represent it as a mesh-independent discontinuity. For such an analysis, the detailed fracture model can be constructed to represent the material in the vicinity of the flaw.…”

Summary of Grizzly Development for Advanced Reactor Structural Materials

“…XFEM development in MOOSE was originally motivated by the need to model discrete fracture in ceramic nuclear fuel [2,3], and used within the Bison application. There is also a significant need for modeling fracture in structural nuclear power plant components, and those needs have largely driven further development of XFEM in MOOSE, particularly for 3D fracture [4,5]. The XFEM implementation in MOOSE is particularly powerful because it inherently represents discontinuities caused by the presence of the crack in all solution fields in a multiphysics analysis.…”

“…4 shows the mesh and crack for each of these tests. These test examples represent a wide range of possible cutting scenarios.…”

Improved Fracture Models for Relocation Modeling

“…For some time, a capability has existed in MOOSE to evaluate interaction integrals to obtain the mixed-mode stress intensity factors and . This was originally developed for mesh-conforming cracks [4], and was later modified to permit use with XFEM [5]. The development of this capability was motivated by the need to assess the probability of fracture initiation at the locations of flaws in embrittled reactor pressure vessels for the Department of Energy's Light Water Reactor Sustainability (LWRS) program.…”