Compute Axisymmetric RZ Finite Strain

Compute a strain increment for finite strains under axisymmetric assumptions.

Description

The material ComputeAxisymmetricRZFiniteStrain calculates the finite strain for 2D Axisymmetric systems.

Axisymmetric (cylindrical) materials are included in Tensor Mechanics for revolved geometries and assume symmetrical loading. These 'strain calculator' materials compute the strain within the appropriate coordinate system and rely on specialized AxisymmetricRZ kernels to handle the stress divergence.

warning:Symmetry Assumed About the -axis

The axis of symmetry must lie along the -axis in a or cylindrical coordinate system. This symmetry orientation is required for the calculation of the residual and of the jacobian. See StressDivergenceRZTensors for the residual equation and the germane discussion.

The AxisymmetricRZ material is appropriate for a 2D simulation and assumes symmetry revolved about the z-axis. A 2D formulation of an appropriate simulation problem can reduce the simulation run time while preserving key physics. Axisymmetric simulations are appropriate to problems in which a solid is generated by revolving a planar area about an axis in the same plane.

note:Use RZ Coordinate Type

The coordinate type in the Problem block of the input file must be set to COORD_TYPE = RZ.

Axisymmetric Strain Formulation

The axisymmetric model employs the cylindrical coordinates, , , and , where the planar cross section formed by the and axes is rotated about the axial axis, along the length of the cylinder, in the direction. The cylindrical coordinate system strain tensor for axisymmetric problems has the form

(1) where the value of the strain depends on the displacement and position in the radial direction (2)

Although axisymmetric problems solve for 3D stress and strain fields, the problem is mathematically 2D. Using an appropriate set of geometry and boundary conditions, these types of problems have strain and stress fields which are not functions of the out of plane coordinate variable. In the cylindrical coordinate axisymmetric system, the values of stress and strain in the direction do not depend on the coordinate.

note:Notation Order Change

The axisymmetric system changes the order of the displacement vector from , usually seen in textbooks, to . Take care to follow this convention in your input files and when adding eigenstrains or extra stresses.

Once the deformation gradient is calculated for the specific 2D geometry, the deformation gradient is passed to the strain and rotation methods used by default 3D Cartesian simulations, as described in the Finite Strain Class page.

Example Input File

[./strain1]
  type = ComputeAxisymmetricRZFiniteStrain
  block = 1
[../]
(modules/combined/test/tests/cavity_pressure/cavity_pressure_rz.i)

Input Parameters

  • displacementsThe displacements appropriate for the simulation geometry and coordinate system

    C++ Type:std::vector

    Options:

    Description:The displacements appropriate for the simulation geometry and coordinate system

Required Parameters

  • global_strainOptional material property holding a global strain tensor applied to the mesh as a whole

    C++ Type:MaterialPropertyName

    Options:

    Description:Optional material property holding a global strain tensor applied to the mesh as a whole

  • decomposition_methodTaylorExpansionMethods to calculate the strain and rotation increments

    Default:TaylorExpansion

    C++ Type:MooseEnum

    Options:TaylorExpansion EigenSolution

    Description:Methods to calculate the strain and rotation increments

  • computeTrueWhen false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

    Default:True

    C++ Type:bool

    Options:

    Description:When false, MOOSE will not call compute methods on this material. The user must call computeProperties() after retrieving the Material via MaterialPropertyInterface::getMaterial(). Non-computed Materials are not sorted for dependencies.

  • base_nameOptional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

    C++ Type:std::string

    Options:

    Description:Optional parameter that allows the user to define multiple mechanics material systems on the same block, i.e. for multiple phases

  • eigenstrain_namesList of eigenstrains to be applied in this strain calculation

    C++ Type:std::vector

    Options:

    Description:List of eigenstrains to be applied in this strain calculation

  • out_of_plane_directionzThe direction of the out-of-plane strain.

    Default:z

    C++ Type:MooseEnum

    Options:x y z

    Description:The direction of the out-of-plane strain.

  • volumetric_locking_correctionFalseFlag to correct volumetric locking

    Default:False

    C++ Type:bool

    Options:

    Description:Flag to correct volumetric locking

  • boundaryThe list of boundary IDs from the mesh where this boundary condition applies

    C++ Type:std::vector

    Options:

    Description:The list of boundary IDs from the mesh where this boundary condition applies

  • blockThe list of block ids (SubdomainID) that this object will be applied

    C++ Type:std::vector

    Options:

    Description:The list of block ids (SubdomainID) that this object will be applied

Optional Parameters

  • output_propertiesList of material properties, from this material, to output (outputs must also be defined to an output type)

    C++ Type:std::vector

    Options:

    Description:List of material properties, from this material, to output (outputs must also be defined to an output type)

  • outputsnone Vector of output names were you would like to restrict the output of variables(s) associated with this object

    Default:none

    C++ Type:std::vector

    Options:

    Description:Vector of output names were you would like to restrict the output of variables(s) associated with this object

Outputs Parameters

  • control_tagsAdds user-defined labels for accessing object parameters via control logic.

    C++ Type:std::vector

    Options:

    Description:Adds user-defined labels for accessing object parameters via control logic.

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Options:

    Description:Set the enabled status of the MooseObject.

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Options:

    Description:The seed for the master random number generator

  • implicitTrueDetermines whether this object is calculated using an implicit or explicit form

    Default:True

    C++ Type:bool

    Options:

    Description:Determines whether this object is calculated using an implicit or explicit form

  • constant_onNONEWhen ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

    Default:NONE

    C++ Type:MooseEnum

    Options:NONE ELEMENT SUBDOMAIN

    Description:When ELEMENT, MOOSE will only call computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps.When SUBDOMAIN, MOOSE will only call computeSubdomainProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped

Advanced Parameters

Input Files