CappedDruckerPragerCosseratStressUpdate

under construction:Undocumented Class

The CappedDruckerPragerCosseratStressUpdate has not been documented. The content contained on this page includes the basic documentation associated with a MooseObject; however, what is contained is ultimately determined by what is necessary to make the documentation clear for users.

Capped Drucker-Prager plasticity stress calculator for the Cosserat situation where the host medium (ie, the limit where all Cosserat effects are zero) is isotropic. Note that the return-map flow rule uses an isotropic elasticity tensor built with the 'host' properties defined by the user.

Input Parameters

  • yield_function_tolThe return-map process will be deemed to have converged if all yield functions are within yield_function_tol of zero. If this is set very low then precision-loss might be encountered: if the code detects precision loss then it also deems the return-map process has converged.

    C++ Type:double

    Options:

    Description:The return-map process will be deemed to have converged if all yield functions are within yield_function_tol of zero. If this is set very low then precision-loss might be encountered: if the code detects precision loss then it also deems the return-map process has converged.

  • tip_smootherThe cone vertex at J2 = 0 will be smoothed by the given amount. Typical value is 0.1*cohesion

    C++ Type:double

    Options:

    Description:The cone vertex at J2 = 0 will be smoothed by the given amount. Typical value is 0.1*cohesion

  • smoothing_tolIntersections of the yield surfaces will be smoothed by this amount (this is measured in units of stress). Often this is related to other physical parameters (eg, 0.1*cohesion) but it is important to set this small enough so that the individual yield surfaces do not mix together in the smoothing process to produce a result where no stress is admissible (for example, mixing together tensile and compressive failure envelopes).

    C++ Type:double

    Options:

    Description:Intersections of the yield surfaces will be smoothed by this amount (this is measured in units of stress). Often this is related to other physical parameters (eg, 0.1*cohesion) but it is important to set this small enough so that the individual yield surfaces do not mix together in the smoothing process to produce a result where no stress is admissible (for example, mixing together tensile and compressive failure envelopes).

  • DP_modelA TensorMechanicsPlasticDruckerPrager UserObject that defines the Drucker-Prager parameters (cohesion, friction angle and dilation angle)

    C++ Type:UserObjectName

    Options:

    Description:A TensorMechanicsPlasticDruckerPrager UserObject that defines the Drucker-Prager parameters (cohesion, friction angle and dilation angle)

  • host_youngs_modulusYoung's modulus for the isotropic host medium

    C++ Type:double

    Options:

    Description:Young's modulus for the isotropic host medium

  • tensile_strengthA TensorMechanicsHardening UserObject that defines hardening of the tensile strength. In physical situations this is positive (and always must be greater than negative compressive-strength.

    C++ Type:UserObjectName

    Options:

    Description:A TensorMechanicsHardening UserObject that defines hardening of the tensile strength. In physical situations this is positive (and always must be greater than negative compressive-strength.

  • host_poissons_ratioPoisson's ratio for the isotropic host medium

    C++ Type:double

    Options:

    Description:Poisson's ratio for the isotropic host medium

  • compressive_strengthA TensorMechanicsHardening UserObject that defines hardening of the compressive strength. In physical situations this is positive.

    C++ Type:UserObjectName

    Options:

    Description:A TensorMechanicsHardening UserObject that defines hardening of the compressive strength. In physical situations this is positive.

Required Parameters

  • small_dilationTrueIf true, and if the trial stress exceeds the tensile strength, then the user gaurantees that the returned stress will be independent of the compressive strength.

    Default:True

    C++ Type:bool

    Options:

    Description:If true, and if the trial stress exceeds the tensile strength, then the user gaurantees that the returned stress will be independent of the compressive strength.

  • min_step_size1In order to help the Newton-Raphson procedure, the applied strain increment may be applied in sub-increments of size greater than this value. Usually it is better for Moose's nonlinear convergence to increase max_NR_iterations rather than decrease this parameter.

    Default:1

    C++ Type:double

    Options:

    Description:In order to help the Newton-Raphson procedure, the applied strain increment may be applied in sub-increments of size greater than this value. Usually it is better for Moose's nonlinear convergence to increase max_NR_iterations rather than decrease this parameter.

  • admissible_stressA single admissible value of the value of the stress parameters for internal parameters = 0. This is used to initialize the return-mapping algorithm during the first nonlinear iteration. If not given then it is assumed that stress parameters = 0 is admissible.

    C++ Type:std::vector

    Options:

    Description:A single admissible value of the value of the stress parameters for internal parameters = 0. This is used to initialize the return-mapping algorithm during the first nonlinear iteration. If not given then it is assumed that stress parameters = 0 is admissible.

  • base_nameOptional parameter that defines a prefix for all material properties related to this stress update model. This allows for multiple models of the same type to be used without naming conflicts.

    C++ Type:std::string

    Options:

    Description:Optional parameter that defines a prefix for all material properties related to this stress update model. This allows for multiple models of the same type to be used without naming conflicts.

  • perform_finite_strain_rotationsFalseTensors are correctly rotated in finite-strain simulations. For optimal performance you can set this to 'false' if you are only ever using small strains

    Default:False

    C++ Type:bool

    Options:

    Description:Tensors are correctly rotated in finite-strain simulations. For optimal performance you can set this to 'false' if you are only ever using small strains

  • max_NR_iterations20Maximum number of Newton-Raphson iterations allowed during the return-map algorithm

    Default:20

    C++ Type:unsigned int

    Options:

    Description:Maximum number of Newton-Raphson iterations allowed during the return-map algorithm

  • perfect_guessTrueProvide a guess to the Newton-Raphson proceedure that is the result from perfect plasticity. With severe hardening/softening this may be suboptimal.

    Default:True

    C++ Type:bool

    Options:

    Description:Provide a guess to the Newton-Raphson proceedure that is the result from perfect plasticity. With severe hardening/softening this may be suboptimal.

  • 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

  • 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

  • warn_about_precision_lossFalseOutput a message to the console every time precision-loss is encountered during the Newton-Raphson process

    Default:False

    C++ Type:bool

    Options:

    Description:Output a message to the console every time precision-loss is encountered during the Newton-Raphson process

Optional Parameters

  • enableTrueSet the enabled status of the MooseObject.

    Default:True

    C++ Type:bool

    Options:

    Description:Set the enabled status of the MooseObject.

  • use_displaced_meshFalseWhether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

    Default:False

    C++ Type:bool

    Options:

    Description:Whether or not this object should use the displaced mesh for computation. Note that in the case this is true but no displacements are provided in the Mesh block the undisplaced mesh will still be used.

  • 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.

  • 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

  • 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

Input Files

References