Finite Strain Crystal Plasticity

Crystal Plasticity base class: FCC system with power law flow rule implemented

Description

warning

The FiniteStrainCrystalPlasticity model is maintained but not actively developed. Use of the FiniteStrainUObasedCP crystal plasticity system is recommend instead.

Constitutive models are used to calculate the plastic slip rate. In this crystal plasticity material the slip rate is modeled as a power law: (1) where is a reference slip rate, is the applied shear stress on each slip system , is the slip system strength, or resistance to slip, and is the strain rate sensitivity exponent. The strength of each slip system is solved with an iterative process as a function of the slip increment (2) where is a hardening coefficient matrix that accounts for the different in self and latent hardening, Eq. (3), is an initial hardening term, is a constant saturated hardening value, and is the hardening exponent (Kalidindi et al., 1992). The self and latent hardening of the crystal is defined for an FCC system as (3) where is a constant value of latent hardening among non-coplanar slip systems. In Eq. (3) the slip systems which share the same slip plane normal (e.g. ) are coplanar and grouped together with a latent hardening rate of unity (Kalidindi et al., 1992). Each matrix entry in Eq. (3) represents the interaction among two different coplanar slip system groups, that is a total of six slip systems (Kalidindi et al., 1992).

In this class, the crystal strain and stress response with response to the residual calculated by the second Piola-Kirchoff stress increment. In contrast, in FiniteStrainCPSlipRateRes the convergence of the crystal plasticity strain and stress response is determined with respect to the slip rate on each slip system of the crystal plasticity model.

Units Assumed in the Crystal Plasticity Materials

The simulation domain for crystal plasticity models is resolved on the order of individual crystal grains, and, as such, the mesh size is small. Although MOOSE itself is dimension agnostic, the crystal plasticity models are implemented in the mm-MPa-s unit system. This dimension system choice impacts the input files in the following manner:

  • Mesh dimensions should be constructed in mm

  • Elastic constant values (e.g. Young's modulus and shear modulus) are entered in MPa

  • Initial slip system strength values are entered in MPa

  • Simulation times are given in s

  • Strain rates and displacement loading rates are given in 1/s and mm/s, respectively

In physically based models, which maybe based on this class, initial densities of crystal defects (e.g. dislocations, point defects) should be given in 1/mm or 1/mm

Input Parameters

  • nssNumber of slip systems

    C++ Type:int

    Options:

    Description:Number of slip systems

  • slip_sys_file_nameName of the file containing the slip system

    C++ Type:FileName

    Options:

    Description:Name of the file containing the slip system

Required Parameters

  • abs_tol1e-06Constitutive stress residue absolute tolerance

    Default:1e-06

    C++ Type:double

    Options:

    Description:Constitutive stress residue absolute tolerance

  • 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

  • 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

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

  • 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

  • flowpropsParameters used in slip rate equations

    C++ Type:std::vector

    Options:

    Description:Parameters used in slip rate equations

  • gen_random_stress_flagFalseFlag to generate random stress to perform time cutback on constitutive failure

    Default:False

    C++ Type:bool

    Options:

    Description:Flag to generate random stress to perform time cutback on constitutive failure

  • gpropsInitial values of slip system resistances

    C++ Type:std::vector

    Options:

    Description:Initial values of slip system resistances

  • gtol100Constitutive slip system resistance residual tolerance

    Default:100

    C++ Type:double

    Options:

    Description:Constitutive slip system resistance residual tolerance

  • hpropsHardening properties

    C++ Type:std::vector

    Options:

    Description:Hardening properties

  • input_random_scaling_varFalseFlag to input scaling variable: _Cijkl(0,0,0,0) when false

    Default:False

    C++ Type:bool

    Options:

    Description:Flag to input scaling variable: _Cijkl(0,0,0,0) when false

  • intvar_read_typenoneRead from options for initial value of internal variables: Default from .i file

    Default:none

    C++ Type:MooseEnum

    Options:slip_sys_file slip_sys_res_file none

    Description:Read from options for initial value of internal variables: Default from .i file

  • line_search_maxiter20Line search bisection method maximum number of iteration

    Default:20

    C++ Type:unsigned int

    Options:

    Description:Line search bisection method maximum number of iteration

  • line_search_methodCUT_HALFThe method used in line search

    Default:CUT_HALF

    C++ Type:MooseEnum

    Options:CUT_HALF BISECTION

    Description:The method used in line search

  • line_search_tol0.5Line search bisection method tolerance

    Default:0.5

    C++ Type:double

    Options:

    Description:Line search bisection method tolerance

  • maximum_substep_iteration1Maximum number of substep iteration

    Default:1

    C++ Type:unsigned int

    Options:

    Description:Maximum number of substep iteration

  • maxiter100Maximum number of iterations for stress update

    Default:100

    C++ Type:unsigned int

    Options:

    Description:Maximum number of iterations for stress update

  • maxitergss100Maximum number of iterations for slip system resistance update

    Default:100

    C++ Type:unsigned int

    Options:

    Description:Maximum number of iterations for slip system resistance update

  • min_line_search_step_size0.01Minimum line search step size

    Default:0.01

    C++ Type:double

    Options:

    Description:Minimum line search step size

  • num_slip_sys_flowrate_props2Number of flow rate properties for a slip system

    Default:2

    C++ Type:unsigned int

    Options:

    Description:Number of flow rate properties for a slip system

  • num_slip_sys_props0Number of slip system specific properties provided in the file containing slip system normals and directions

    Default:0

    C++ Type:unsigned int

    Options:

    Description:Number of slip system specific properties provided in the file containing slip system normals and directions

  • random_scaling_var1e+09Random scaling variable: Large value can cause non-positive definiteness

    Default:1e+09

    C++ Type:double

    Options:

    Description:Random scaling variable: Large value can cause non-positive definiteness

  • random_seed2000Random integer used to generate random stress when constitutive failure occurs

    Default:2000

    C++ Type:unsigned int

    Options:

    Description:Random integer used to generate random stress when constitutive failure occurs

  • read_prop_user_objectThe ElementReadPropertyFile GeneralUserObject to read element specific property values from file

    C++ Type:UserObjectName

    Options:

    Description:The ElementReadPropertyFile GeneralUserObject to read element specific property values from file

  • rtol1e-06Constitutive stress residue relative tolerance

    Default:1e-06

    C++ Type:double

    Options:

    Description:Constitutive stress residue relative tolerance

  • slip_incr_tol0.02Maximum allowable slip in an increment

    Default:0.02

    C++ Type:double

    Options:

    Description:Maximum allowable slip in an increment

  • slip_sys_flow_prop_file_nameName of the file containing the values of slip rate equation parameters

    C++ Type:FileName

    Options:

    Description:Name of the file containing the values of slip rate equation parameters

  • slip_sys_hard_prop_file_nameName of the file containing the values of hardness evolution parameters

    C++ Type:FileName

    Options:

    Description:Name of the file containing the values of hardness evolution parameters

  • slip_sys_res_prop_file_nameName of the file containing the initial values of slip system resistances

    C++ Type:FileName

    Options:

    Description:Name of the file containing the initial values of slip system resistances

  • tan_mod_typenoneType of tangent moduli for preconditioner: default elastic

    Default:none

    C++ Type:MooseEnum

    Options:exact none

    Description:Type of tangent moduli for preconditioner: default elastic

  • use_line_searchFalseUse line search in constitutive update

    Default:False

    C++ Type:bool

    Options:

    Description:Use line search in constitutive update

Optional 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.

  • 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

  • seed0The seed for the master random number generator

    Default:0

    C++ Type:unsigned int

    Options:

    Description:The seed for the master random number generator

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

Child Objects

References

  1. Surya R Kalidindi, Curt A Bronkhorst, and Lallit Anand. Crystallographic texture evolution in bulk deformation processing of fcc metals. Journal of the Mechanics and Physics of Solids, 40(3):537–569, 1992.[BibTeX]