XFEM System Design Description

This template follows INL template TEM-140, "IT System Design Description."

commentnote

This document serves as an addendum to Framework System Design Description and captures information for SDD specific to the XFEM module.

Introduction

The physics models in MOOSE typically represent spatially continuous behavior, for which the finite element method is well suited. However, discontinuities can arise in the physical systems being modeled, and representing those discontinuities can be challenging, especially when they move or grow, as is the case for moving material interfaces or propagating cracks. The MOOSE XFEM module provides capabilities to represent arbitrary, mesh-independent discontinuities in physical solutions using the extended finite element method. This module relies on MOOSE for solving its system of equations, and is designed to be flexible in its ability to introduce discontinuities to arbitrary physics models. This document describes the system design of the XFEM module.

System Purpose

The Software Design Description provided here is description of each object in the system. The pluggable architecture of the underlying framework of the XFEM module makes MOOSE and MOOSE-based applications straightforward to develop as each piece of end-user (developer) code that goes into the system follows a well-defined interface for the underlying systems that those object plug into. These descriptions are provided through developer-supplied "markdown" files that are required for all new objects that are developed as part of the XFEM module. More information about the design documentation for MOOSE-based applications and like the XFEM module can be found in Documenting MOOSE.

System Scope

The MOOSE XFEM module provides capabilities for representing mesh-independent discontinuities in a finite-element model. This is done using the phantom-node variant of the extended finite element method, which introduces discontinuities by duplicating elements cut by the discontinuity, re-connecting those elements to the mesh in an appropriate way, and modifying the integration rule of these cut elements to reflect the fact that only part of the elements represent physical material.

This module provides all of the capabilities needed to use phantom-node-based XFEM. The core of this capability is the cutting algorithm, known as the element fragment algorithm (EFA). The EFA determines which elements should be deleted and added, and which nodes should be added. The XFEM module provides all the capabilities needed to store and use data about the elements that have been cut, and to modify the integration rules for those cut elements.

The XFEM module also provides capabilities for the user to define how the mesh is cut in a variety of ways, including based on primitive geometric objects, meshes, level set fields, or paths determined by stresses or fracture integrals. For crack propagation based on fracture integrals, the XFEM module can provide the information on crack geometry needed to compute those integrals, which are computed externally to this module.

In addition, the XFEM module contains tools to support the setup of models that use XFEM and outputting relevant data for use in visualizing results.

Dependencies and Limitations

The MOOSE XFEM module inherits the software dependencies of the MOOSE framework and Solid Mechanics module with no additional dependencies.

Definitions and Acronyms

This section defines, or provides the definition of, all terms and acronyms required to properly understand this specification.

Definitions

  • Pull (Merge) Request: A proposed change to the software (e.g. usually a code change, but may also include documentation, requirements, design, and/or testing).

  • Baseline: A specification or product (e.g., project plan, maintenance and operations (M&O) plan, requirements, or design) that has been formally reviewed and agreed upon, that thereafter serves as the basis for use and further development, and that can be changed only by using an approved change control process (NQA-1, 2009).

  • Validation: Confirmation, through the provision of objective evidence (e.g., acceptance test), that the requirements for a specific intended use or application have been fulfilled (24765:2010(E), 2010).

  • Verification: (1) The process of: evaluating a system or component to determine whether the products of a given development phase satisfy the conditions imposed at the start of that phase. (2) Formal proof of program correctness (e.g., requirements, design, implementation reviews, system tests) (24765:2010(E), 2010).

Acronyms

AcronymDescription
APIApplication Programming Interface
DOE-NEDepartment of Energy, Nuclear Energy
FEfinite element
HITHierarchical Input Text
HPCHigh Performance Computing
I/OInput/Output
INLIdaho National Laboratory
MOOSEMultiphysics Object Oriented Simulation Environment
MPIMessage Passing Interface
SDDSoftware Design Description

Design Stakeholders and Concerns

Design Stakeholders

Stakeholders for MOOSE include several of the funding sources including DOE-NE and the INL. However, Since MOOSE is an open-source project, several universities, companies, and foreign governments have an interest in the development and maintenance of the MOOSE project.

Stakeholder Design Concerns

Concerns from many of the stakeholders are similar. These concerns include correctness, stability, and performance. The mitigation plan for each of these can be addressed. For correctness, XFEM module development requires either regression or unit testing for all new code added to the repository. The project contains several comparisons against analytical solutions where possible and also other verification methods such as MMS. For stability, the XFEM module (located within the MOOSE repository) maintains multiple branches to incorporate several layers of testing both internally and for dependent applications. Finally, performance tests are also performed as part of the the normal testing suite to monitor code change impacts to performance.

System Design

The MOOSE XFEM module relies on MOOSE to solve the governing equations for arbitrary physics, and provides the additional capabilities needed to introduce spatial discontinuities in those physics models. Discontinuities are introduced using the phantom-node variant of the extended finite element method, which duplicates elements cut by the discontinuity, re-connects those elements to the mesh in an appropriate way, and modifies the integration rule of these cut elements to reflect the fact that only part of the elements represent physical material. The core of this capability is the cutting algorithm, known as the element fragment algorithm (EFA). The EFA determines which elements should be deleted and added, and which nodes should be added. The EFA is designed to have minimal dependencies on MOOSE, and uses its own simple mesh data structures. The EFA mesh is defined using information provided to it about the elements that make up the MOOSE finite element mesh used for the physics solution. Once the EFA identifies the changes to be made to the mesh, the XFEM module modifies the MOOSE mesh, and uses its own data structures to store data about the cut locations that is necessary for integration of the fields that are nonzero over only a portion of the element.

For integration of the fields on the cut elements, the XFEM module uses a moment-fitting method, which uses the original quadrature points, but modifies their weights using values that are obtained through a least-squares procedure. It also provides an option to simply multiply the original quadrature-point weights by the volume fraction of the cut element that represents physical material, which is a special case of the moment-fitting method.

The XFEM module provides the capability for the user to define how the mesh is cut in a variety of ways, including based on primitive geometric objects, meshes, level set fields, or paths determined by stresses or fracture integrals. A base class, based on the MOOSE ElementUserObject, is provided in the XFEM module, which provides a way for cut elements to be identified and have those elements and the cut locations be conveyed to the EFA. A number of objects that derive from that base cut definition class are provided to define cuts in a variety of ways. For crack propagation based on fracture integrals, the XFEM module can provide the information on crack geometry needed to compute those integrals to the Solid Mechanics module, which computes those integrals. If those fracture integrals indicate that a crack should be extended, the cut definition is modified to reflect those changes. The design of MOOSE is based on the concept of modular code objects that define all of the aspects of the physics model. Although there are specialized capabilities in XFEM that fall outside the standard MOOSE base classes, wherever it is possible, this module follows this design, providing code objects that define specific aspects of the solutions for its physics that derive from the base classes defined by the MOOSE framework and the modules that it depends on.

System Structure

The MOOSE XFEM module relies on the MOOSE framework to provide the core functionality of solving multiphysics problems using the finite element method, and on other physics modules to solve for the continuous solutions that are enriched using the extended finite element method. Although the XFEM module is designed to operate with arbitrary physics, there are models specific to fracture propagation that are designed to operate specifically with the Solid Mechanics module. The structure of the XFEM module is based on defining C++ classes that derive from classes in the MOOSE framework to provide needed functionality wherever possible. By using the interfaces defined in MOOSE base classes for these classes, this module is able to rely on MOOSE to execute these models at the appropriate times during the simulation and use their results in the desired ways.

Data Design and Control

At a high level, the system is designed to process HIT input files to construct several objects that will constitute an FE simulation. Some of the objects in the simulation may in turn load other file-based resources to complete the simulation. Examples include meshes or data files. The system will then assemble systems of equations and solve them using the libraries of the Code Platform. The system can then output the solution in one or more supported output formats commonly used for visualization.

Human-Machine Interface Design

The XFEM module is a command-line driven program. All interaction with the XFEM module is ultimately done through the command line. This is typical for HPC applications that use the MPI interface for running on super computing clusters. Optional GUIs may be used to assist in creating input files and launching executables on the command line.

System Design Interface

All external system interaction is performed either through file I/O or through local API calls. Neither the XFEM module, nor the MOOSE framework, nor the other MOOSE modules are designed to interact with any external system directly through remote procedure calls. Any code to code coupling performed using the framework are done directly through API calls either in a static binary or after loading shared libraries.

Security Structure

The XFEM module does not require any elevated privileges to operate and does not run any stateful services, daemons or other network programs. Distributed runs rely on the MPI library.

Requirements Cross-Reference

  • xfem: LevelSetCutUserObject
  • 22.1.1The XFEM module shall have the capability to calculate mechanical response in two glued, layered materials with the interface location and material properties applied to on each side of the boundary determined by a level set function.

    Specification(s): glued_bimaterial

    Design: LevelSetCutUserObjectXFEMSingleVariableConstraint

    Issue(s): #10421

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.1.2The XFEM module shall have the capability to calculate mechanical response in a composite material matrix with an inclusion with the location of the inclusion boundary and material properties applied to the matrix and inclusion determined by a prescribed level set function.

    Specification(s): inclusion_bimaterial

    Design: LevelSetCutUserObjectXFEMSingleVariableConstraint

    Issue(s): #10421

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.5.3The XFEM Module shall have the capability to run 2D diffusion problems with a fixed position discontinuous interface defined by the location of the zero values of a level set function with the level set variable being a Moose Variable.

    Specification(s): levelsetcut2d

    Design: LevelSetCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.5.4The XFEM Module shall have the capability to run 2D diffusion problems with a fixed position discontinuous interface defined by the location of the zero values of a prescribed level set function with the level set variable being a Moose AuxVariable.

    Specification(s): levelsetcut2d_aux

    Design: LevelSetCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.5.5The XFEM Module shall have the capability to run 3D diffusion problems with a fixed position discontinuous interface defined by the location of the zero values of a prescribed level set function with the level set variable being a Moose AuxVariable.

    Specification(s): levelsetcut3d

    Design: LevelSetCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.1The XFEM module shall provide an ability to specify whether an XFEM cut surface should be healed independently for individual interfaces

    Specification(s): moving_interface

    Design: LineSegmentCutSetUserObjectLevelSetCutUserObject

    Issue(s): #11259

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.10The XFEM module shall provide an ability to solve bi-material diffusion problems where a moving material interface is defined by an XFEM surface, which is defined by a prescribed level set field.

    Specification(s): moving_diffusion

    Design: LevelSetBiMaterialRealXFEMEqualValueAtInterfaceLevelSetCutUserObject

    Issue(s): #11749

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    8
  • 22.11.17The XFEM module shall accurately solve 1D, xy problems with homogeneous material properties with a moving interface determined by a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 1D_xy_homog1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.18The XFEM module shall accurately solve 1D, xy problems with material properties and a moving interface dependent on a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 1D_xy_lsdep1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.19The XFEM module shall accurately solve 1D, xy problems with a moving interface separating two discrete materials prescribed by a user defined level set function with problem results verified using the Method of Manufactured Solutions.

    Specification(s): 1D_xy_discrete2mat

    Design: LevelSetCutUserObjectXFEMSingleVariableConstraint

    Issue(s): #13756

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.20The XFEM module shall accurately solve 1D, rz problems with homogeneous material properties with a moving interface determined by a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 1D_rz_homog1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.21The XFEM module shall accurately solve 1D, rz problems with material properties and a moving interface dependent on a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 1D_rz_lsdep1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.22The XFEM module shall accurately solve 2D, xy problems with homogeneous material properties with a moving interface determined by a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 2D_xy_homog1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.23The XFEM module shall accurately solve 2D, xy problems with material properties and a moving interface dependent on a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 2D_xy_lsdep1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.24The XFEM module shall accurately solve 2D, rz problems with homogeneous material properties with a moving interface determined by a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 2D_rz_homog1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.25The XFEM module shall accurately solve 2D, rz problems with material properties and a moving interface dependent on a user prescribed level set function, and problem results are verified using the Method of Manufactured Solutions.

    Specification(s): 2D_rz_lsdep1mat

    Design: LevelSetCutUserObject

    Issue(s): #12833

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • xfem: Checkpoint
  • 22.2.1The XFEM module shall support outputting of checkpoint files.

    Specification(s): checkpoint

    Design: Checkpoint

    Issue(s): #17063

    Collection(s): FUNCTIONAL

    Type(s): CheckFiles

    66
  • xfem: LineSegmentCutUserObject
  • 22.3.1The XFEM module shall have the capability of cutting directly through multiple nodes of a single QUAD4 element in 2D.

    Specification(s): corner_node_cut_twice

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.3.2The XFEM module shall be able to perform mesh cuts on any combination of the edges of elements and through elements including allowing cuts that go through the nodes on the same mesh.

    Specification(s): corner_edge_cut

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.3.3The XFEM module shall have the capability of perfoming mesh cuts on the edges of elements such that only two new nodes are generated to separate the previously connected elements.

    Specification(s): corner_node_cut

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.3.4The XFEM module shall be capable of propagating an existing crack front along a prescribed cut in 2D.

    Specification(s): notch

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.4.1The XFEM module shall have the capability to include near-tip enrichment functions in 2D mechanics simulations.

    Specification(s): crack_tip_enrichment_edge_2d

    Design: LineSegmentCutUserObjectCrackTipEnrichmentStressDivergenceTensors

    Issue(s): #10042

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.5.1The XFEM Module shall have the capability to run 2D diffusion problems with prescribed values on the domain boundary (Dirichlet conditions) with a fixed position discontinuous interface through mesh elements.

    Specification(s): diffusion_xfem

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.5.2The XFEM Module shall have the capability to run 2D diffusion problems with prescribed solution values on the domain boundary (Dirichlet conditions) and prescribed boundary flux values (Neumann conditions) with a fixed position discontinuous interface defined by a geometric cut user object.

    Specification(s): diffusion_xfem_flux_bc

    Design: LineSegmentCutUserObject

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • xfem: XFEM
  • 22.6.1The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 2D using TRI6 elements.

    Specification(s): diffusion_2d_tri6

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.2The XFEM module shall permit modeling of discontinuities represented with XFEM with third-order elements in 2D using TRI7 elements.

    Specification(s): diffusion_2d_tri7

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.3The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 2D using QUAD8 elements.

    Specification(s): diffusion_2d_quad8

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.4The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 2D using QUAD9 elements.

    Specification(s): diffusion_2d_quad9

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.5The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 2D using QUAD9 elements when the XFEM cutting plane is prescribed using a level set field.

    Specification(s): diffusion_quad9_levelsetcut

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.6The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 3D using TET10 elements when the XFEM cutting plane is prescribed using a level set field.

    Specification(s): diffusion_3d_tet10

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.7The XFEM module shall permit modeling of discontinuities represented with XFEM with third-order elements in 3D using TET14 elements when the XFEM cutting plane is prescribed using a level set field.

    Specification(s): diffusion_3d_tet14

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.8The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 3D using HEX20 elements when the XFEM cutting plane is prescribed using a level set field.

    Specification(s): diffusion_3d_hex20

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.9The XFEM module shall permit modeling of discontinuities represented with XFEM with second-order elements in 3D using HEX27 elements when the XFEM cutting plane is prescribed using a level set field.

    Specification(s): diffusion_3d_hex27

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.10The XFEM module shall permit modeling of branching of discontinuities represented with XFEM by sequentially cutting second-order elements in 2D using QUAD8 elements.

    Specification(s): square_branch_quad8_2d

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.11The XFEM module shall permit modeling of branching of discontinuities represented with XFEM by sequentially cutting second-order elements in 2D using QUAD9 elements.

    Specification(s): square_branch_quad9_2d

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.12The XFEM module shall permit modeling of branching of discontinuities represented with XFEM by sequentially cutting second-order elements in 2D using TRI6 elements.

    Specification(s): square_branch_tri6_2d

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.6.13The XFEM module shall permit modeling of branching of discontinuities represented with XFEM by sequentially cutting third-order elements in 2D using TRI7 elements.

    Specification(s): square_branch_tri7_2d

    Design: XFEM

    Issue(s): #8709

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.7.1The XFEM module shall retain the values of auxiliary variables on child nodes and elements after running the cutting algorithm, and initialize solution variables on newly created nodes with values from parent nodes in parallel

    Specification(s): init_solution_propagation

    Design: XFEM

    Issue(s): #8763

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.8.1The XFEM module shall permit applying a glued constraint across the XFEM interface for 2D solid mechanics problems.

    Specification(s): glued_penalty

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    138
  • 22.10.1The XFEM module shall permit the use of the moment fitting algorithm to compute integration point weights for partial elements on 2D solid mechanics problems

    Specification(s): solid_mechanics_moment_fitting

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.10.2The XFEM module shall permit the use of the moment fitting algorithm to compute integration point weights for partial elements on 2D problems with a 4-point integration rule

    Specification(s): diffusion_moment_fitting_four_points

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.10.3The XFEM module shall permit the use of the moment fitting algorithm to compute integration point weights for partial elements on 2D problems with a 6-point integration rule

    Specification(s): diffusion_moment_fitting_six_points

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.11.2The XFEM module shall not output summary information on mesh changes when debug_output_level=0

    Specification(s): moving_interface_debug_output_0

    Design: XFEM

    Issue(s): #13666

    Collection(s): FUNCTIONAL

    Type(s): RunApp

    66
  • 22.11.3The XFEM module shall output summary information on mesh changes when debug_output_level=1

    Specification(s): moving_interface_debug_output_1

    Design: XFEM

    Issue(s): #13666

    Collection(s): FUNCTIONAL

    Type(s): RunApp

    66
  • 22.11.4The XFEM module shall output detailed information on mesh changes when debug_output_level=2

    Specification(s): moving_interface_debug_output_2

    Design: XFEM

    Issue(s): #13666

    Collection(s): FUNCTIONAL

    Type(s): RunApp

    66
  • 22.11.5The XFEM module shall output detailed information on mesh changes when debug_output_level=3

    Specification(s): moving_interface_debug_output_3

    Design: XFEM

    Issue(s): #13666

    Collection(s): FUNCTIONAL

    Type(s): RunApp

    66
  • 22.14.1The XFEM module shall properly integrate quantities on sides of cut elements that are intersected by the cutting plane in 2D

    Specification(s): side_integral_xfem

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.14.2The XFEM module shall properly integrate quantities on sides of cut elements that are intersected by the cutting plane in 3D

    Specification(s): side_integral_3d_xfem

    Design: XFEM

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.17.8The XFEM system shall permit branched cracks to be represented in 2D by sequentially cutting a 4-noded quadrilateral element by two prescribed evolving cutting planes

    Specification(s): square_branch_quad_2d

    Design: XFEM

    Issue(s): #6320#23572

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.17.9The XFEM system shall permit branched cracks to be represented in 2D by sequentially cutting a 3-noded triangle element by two prescribed evolving cutting planes

    Specification(s): square_branch_tri_2d

    Design: XFEM

    Issue(s): #6320#23572

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.17.10The XFEM system shall provide an accessor function to the crack_tip_origin_direction_map

    Specification(s): test_crack_counter

    Design: XFEM

    Issue(s): #6320#23572

    Collection(s): FUNCTIONAL

    Type(s): CSVDiff

    66
  • xfem: MeshCut2DFunctionUserObject
  • 22.9.1The XFEM module shall represent a propagating crack in a 2D mechanics model with XFEM, where the crack is defined using a topologically defined surface cutting mesh by MeshCut2DFunctionUserObject
    1. and crack growth and direction is computed by a fracture integral.
    2. and crack growth and direction is computed by a fracture integral or maximum stress criterion.
    3. and crack growth is defined by a function. The average crack tip stress changes with crack orientation and properly accounts volume averaging near surfaces.

    Specification(s): 2D/k_growth, 2D/k_stress_growth, 2D/stress_check

    Design: MeshCut2DFunctionUserObject

    Issue(s): #23572#27659

    Collection(s): FUNCTIONAL

    Type(s): ExodiffCSVDiff

    666666
  • xfem: XFEMPressure
  • 22.13.1The XFEM module shall permit application of pressure boundary conditions to XFEM cut surfaces in 2D

    Specification(s): edge_2d_pressure

    Design: XFEMPressure

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.13.2The XFEM module shall permit application of pressure boundary conditions to XFEM cut surfaces in 3D

    Specification(s): edge_3d_pressure

    Design: XFEMPressure

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.13.3The XFEM module shall permit application of pressure boundary conditions to inclined XFEM cut surfaces in 2D

    Specification(s): inclined_edge_2d_pressure

    Design: XFEMPressure

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • 22.13.4The XFEM module shall permit application of pressure boundary conditions to XFEM cut surfaces in 2D finite deformation simulations

    Specification(s): 2d_pressure_displaced_mesh

    Design: XFEMPressure

    Issue(s): #6320

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    66
  • xfem: CrackMeshCut3DUserObject
  • 22.17.5The XFEM module shall represent a propagating crack in a 3D mechanics model with XFEM, where the crack is defined using a topological surface cutting mesh by CrackMeshCut3DUserObject and allowed to propagate with
    1. growth speeds determined by the fatigue cracking Paris law, or
    2. growth directions determined by computing the maximum hoop stress law using interaction integrals, or
    3. growth directions determined by an parsed function.

    Specification(s): mesh_cutter_3d/fatigue, mesh_cutter_3d/mhs, mesh_cutter_3d/function

    Design: CrackMeshCut3DUserObject

    Issue(s): #6320#23572

    Collection(s): FUNCTIONAL

    Type(s): Exodiff

    666666

References

  1. ISO/IEC/IEEE 24765:2010(E). Systems and software engineering—Vocabulary. first edition, December 15 2010.[BibTeX]
  2. ASME NQA-1. ASME NQA-1-2008 with the NQA-1a-2009 addenda: Quality Assurance Requirements for Nuclear Facility Applications. first edition, August 31 2009.[BibTeX]