- constant_propertiesConstant mechanical and thermal material properties (PROPS)
C++ Type:std::vector<double>
Controllable:No
Description:Constant mechanical and thermal material properties (PROPS)
- num_state_varsThe number of state variables this UMAT is going to use
C++ Type:unsigned int
Controllable:No
Description:The number of state variables this UMAT is going to use
- pluginThe path to the compiled dynamic library for the plugin you want to use
C++ Type:FileName
Controllable:No
Description:The path to the compiled dynamic library for the plugin you want to use
- use_one_based_indexingFalseParameter to control whether indexing for element and integration points as presented to UMAT models is based on 1 (true) or 0 (false). This does not affect internal MOOSE numbering. The option to use 0-based numbering is deprecated and will be removed soon.
Default:False
C++ Type:bool
Controllable:No
Description:Parameter to control whether indexing for element and integration points as presented to UMAT models is based on 1 (true) or 0 (false). This does not affect internal MOOSE numbering. The option to use 0-based numbering is deprecated and will be removed soon.
Abaqus UMAT Stress
Coupling material to use Abaqus UMAT models in MOOSE
Description
AbaqusUMATStress provides an interface for using _Abaqus UMAT_ functions as constitutive models in MOOSE.
UMAT User subroutine interface
UMAT functions are commonly coded in Fortran, are located in the $(APPLICATION_DIR)/plugins and $(APPLICATION_DIR)/test/plugins directories, and are automatically compiled by the MOOSE build system.
A UMAT file my_umat.f can be loaded by the AbaqusUMATStress by providing the the full path and filename without an extension via the "plugin" parameter in the MOOSE input file.
A valid UMAT subroutine has the following call signature
SUBROUTINE UMAT(STRESS,STATEV,DDSDDE,SSE,SPD,SCD,
1 RPL,DDSDDT,DRPLDE,DRPLDT,
2 STRAN,DSTRAN,TIME,DTIME,TEMP,DTEMP,PREDEF,DPRED,CMNAME,
3 NDI,NSHR,NTENS,NSTATV,PROPS,NPROPS,COORDS,DROT,PNEWDT,
4 CELENTCELENT,DFGRD0,DFGRD1,NOEL,NPT,LAYER,KSPT,KSTEP,KINC)
C
CHARACTER*80 CMNAME
DIMENSION STRESS(NTENS),STATEV(NSTATV),
1 DDSDDE(NTENS,NTENS),DDSDDT(NTENS),DRPLDE(NTENS),
2 STRAN(NTENS),DSTRAN(NTENS),TIME(2),PREDEF(1),DPRED(1),
3 PROPS(NPROPS),COORDS(3),DROT(3,3),DFGRD0(3,3),DFGRD1(3,3)
user coding to define DDSDDE, STRESS, STATEV, SSE, SPD, SCD
and, if necessary, RPL, DDSDDT, DRPLDE, DRPLDT, PNEWDT
RETURN
END
A description of the input and output parameters of the UMAT user subroutines can be found in the Abaqus user manual.
Note that the UMAT standard uses 1-based indexing for NOEL (element number) and NPT (integration point number), while MOOSE uses 0-based indexing internally. We therefore add one to the element and integration point numbers from MOOSE before passing them to the UMAT.
UMAT Time step control
Time step control within the UMAT subroutine is used together with MOOSE's general capabilities to control time steps based on material behavior. PNEWDT denotes a factor that can be modified in the UMAT routine to be less than one, to signal a cut in the time step, or more than one, to signal a local increment in the time step. Since these time step controls are local to the quadrature point, MOOSE provides a layer of objects to handle the information provided by UMAT's PNEWDT. First, we select a soft Terminator which will invalidate a time step if the time step increment used turns out to be larger than a computed maximum time step increment anywhere in the system:
[UserObjects]
[time_step_size]
type = TimestepSize
execute_on = 'INITIAL LINEAR'
[]
[terminator_umat]
type = Terminator
expression = 'time_step_size > matl_ts_min'
fail_mode = SOFT
execute_on = 'FINAL'
[]
[]
As a second step, we select the time stepper controls for the entire finite element system. These controls will apply to UMAT stepping as well as any other kernel or object in the system:
[Executioner]
[TimeStepper]
type = IterationAdaptiveDT
optimal_iterations = 30
iteration_window = 9
growth_factor = 2.0
cutback_factor = 1.0
timestep_limiting_postprocessor = matl_ts_min
dt = 1.0
[]
[]
The time step increment will be reduced as prescribed in the UMAT routine. However, the maximum increment will be limited by the selection of growth_factor. This avoids increasing the time step too much from one time step to the next. To further rely on UMAT's PNEWDT, one can choose to select a larger growth_factor.
A subroutine that acts on PNEWDT is chosen in the regression test:
[Materials]
[umat]
type = AbaqusUMATStress
constant_properties = '1000 0.3'
plugin = '../../../plugins/elastic_timestep'
num_state_vars = 0
use_one_based_indexing = true
[]
[]
UMAT Loading steps
When setting up an input file, it can be useful to organize it in terms of the loading and boundary conditions that the structural component will undergo throughout the numerical simulation. For example, a user may want to apply natural boundary conditions as a first step (Step 1), then apply gradually a permanent or long-term load, e.g. the internal pressure in a vessel (Step 2). Finally, other loads, such as those originated by wind, can be added to the existing step to obtain the desired final numerical results (Step 3). For this case, MOOSE steps need to be defined throughout the simulation in StepUserObject. This user object can be passed to AbaqusUMATStress to inform the UMAT routine of the value of step time at the beginning of the current increment (TIME(1) with Fortran indexing).
An example of how to pass the user object in an input file is given below:
[Materials]
[umat]
type = AbaqusUMATStress
constant_properties = '1000 0.3'
plugin = '../../../plugins/elastic_temperature'
num_state_vars = 0
temperature = temperature
use_one_based_indexing = true
[]
[]
Note that the step capability is three-pronged: 1) It allows to pass the step number to the UMAT routine via the present object, 2) It allows to pass the step number to the AbaqusUExternalDB plugin, and 3) It allows to directly drive controls via step number in StepPeriod.
Example input file
[Materials]
[constant]
type = AbaqusUMATStress
# Young's modulus, Poisson's Ratio, Yield, Hardening
constant_properties = '1000 0.3 10 100'
plugin = ../../../plugins/linear_strain_hardening
num_state_vars = 3
use_one_based_indexing = true
[]
[]
Input Parameters
- 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
Controllable:No
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 blocks (ids or names) that this object will be applied
C++ Type:std::vector<SubdomainName>
Controllable:No
Description:The list of blocks (ids or names) that this object will be applied
- boundaryThe list of boundaries (ids or names) from the mesh where this object applies
C++ Type:std::vector<BoundaryName>
Controllable:No
Description:The list of boundaries (ids or names) from the mesh where this object 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
Controllable:No
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 computeQpProperties() 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
Controllable:No
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 computeQpProperties() for the 0th quadrature point, and then copy that value to the other qps. Evaluations on element qps will be skipped
- declare_suffixAn optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any declared properties. The suffix will be prepended with a '_' character.
- decomposition_methodTaylorExpansionMethod to calculate the strain kinematics.
Default:TaylorExpansion
C++ Type:MooseEnum
Controllable:No
Description:Method to calculate the strain kinematics.
- external_fieldsThe external fields that can be used in the UMAT subroutine
C++ Type:std::vector<VariableName>
Controllable:No
Description:The external fields that can be used in the UMAT subroutine
- external_properties
C++ Type:std::vector<MaterialPropertyName>
Controllable:No
- prop_getter_suffixAn optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
C++ Type:MaterialPropertyName
Controllable:No
Description:An optional suffix parameter that can be appended to any attempt to retrieve/get material properties. The suffix will be prepended with a '_' character.
- step_user_objectThe StepUserObject that provides times from simulation loading steps.
C++ Type:UserObjectName
Controllable:No
Description:The StepUserObject that provides times from simulation loading steps.
- temperatureCoupled temperature
C++ Type:std::vector<VariableName>
Controllable:No
Description:Coupled temperature
- use_interpolated_stateFalseFor the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Default:False
C++ Type:bool
Controllable:No
Description:For the old and older state use projected material properties interpolated at the quadrature points. To set up projection use the ProjectedStatefulMaterialStorageAction.
Optional Parameters
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Controllable:No
Description:Adds user-defined labels for accessing object parameters via control logic.
- enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
Controllable:Yes
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
Controllable:No
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
Controllable:No
Description:The seed for the master random number generator
- use_displaced_meshFalseWhether or not this object should use the displaced mesh for computing displacements and quantities based on the deformed state.
Default:False
C++ Type:bool
Controllable:No
Description:Whether or not this object should use the displaced mesh for computing displacements and quantities based on the deformed state.
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<std::string>
Controllable:No
Description:List of material properties, from this material, to output (outputs must also be defined to an output type)
- outputsnone Vector of output names where you would like to restrict the output of variables(s) associated with this object
Default:none
C++ Type:std::vector<OutputName>
Controllable:No
Description:Vector of output names where you would like to restrict the output of variables(s) associated with this object