- disp_xThe x displacement variable
C++ Type:std::vector<VariableName>
Description:The x displacement variable
- disp_yThe y displacement variable
C++ Type:std::vector<VariableName>
Description:The y displacement variable
- friction_lmThe frictional Lagrange's multiplier
C++ Type:std::vector<VariableName>
Description:The frictional Lagrange's multiplier
- muThe friction coefficient for the Coulomb friction law
C++ Type:double
Description:The friction coefficient for the Coulomb friction law
- primary_boundaryThe name of the primary boundary sideset.
C++ Type:BoundaryName
Description:The name of the primary boundary sideset.
- primary_subdomainThe name of the primary subdomain.
C++ Type:SubdomainName
Description:The name of the primary subdomain.
- secondary_boundaryThe name of the secondary boundary sideset.
C++ Type:BoundaryName
Description:The name of the secondary boundary sideset.
- secondary_subdomainThe name of the secondary subdomain.
C++ Type:SubdomainName
Description:The name of the secondary subdomain.
ComputeFrictionalForceLMMechanicalContact
This class represents a preliminary implementation of frictional mortar contact constraints intended to be used with Lagrange's multiplier interpolation with dual bases. The nonlinear complementarity constraints employed here are based on a primal-dual active set strategy (PDASS), see (Gitterle et al., 2010). These constraints capture nodes in sticking and slipping states on different solution branches, and can be written as:
is a Lagrange's multiplier that refers to the tangential contact pressure at node , is the weighted tangential velocity integrated forward in time, is the weighted normal gap, is a numerical parameter ( in ComputeWeightedGapLMMechanicalContact) and is a numerical parameter that can determine convergence properties but has no effect on the results.
The nodal, weighted tangential velocity is computed as
where denotes the secondary contact interface, is the j'th lagrange multiplier test function, and is the discretized version of the tangential velocity function.
This object automatically enforces normal contact constraints by making calls to its parent class ComputeWeightedGapLMMechanicalContact, see ComputeWeightedGapLMMechanicalContact for input parameters and details.
The preliminary recommendation is to select c to be on the order of the moduli of elasticity of the bodies into contact, and c_t to be a few orders of magnitude less than c. This selection of these purely numerical parameters can represent an initial difficulty when running new models, but they can be held constant once good convergence behavior has been attained.
Computes the tangential frictional forces
Input Parameters
- c1e+06Parameter for balancing the size of the gap and contact pressure
Default:1e+06
C++ Type:double
Description:Parameter for balancing the size of the gap and contact pressure
- c_t1Numerical parameter for tangential constraints
Default:1
C++ Type:double
Description:Numerical parameter for tangential constraints
- compute_lm_residualsTrueWhether to compute Lagrange Multiplier residuals
Default:True
C++ Type:bool
Description:Whether to compute Lagrange Multiplier residuals
- compute_primal_residualsTrueWhether to compute residuals for the primal variable.
Default:True
C++ Type:bool
Description:Whether to compute residuals for the primal variable.
- epsilon1e-07Minimum value of contact pressure that will trigger frictional enforcement
Default:1e-07
C++ Type:double
Description:Minimum value of contact pressure that will trigger frictional enforcement
- interpolate_normalsTrueWhether to interpolate the nodal normals (e.g. classic idea of evaluating field at quadrature points). If this is set to false, then non-interpolated nodal normals will be used, and then the _normals member should be indexed with _i instead of _qp
Default:True
C++ Type:bool
Description:Whether to interpolate the nodal normals (e.g. classic idea of evaluating field at quadrature points). If this is set to false, then non-interpolated nodal normals will be used, and then the _normals member should be indexed with _i instead of _qp
- periodicFalseWhether this constraint is going to be used to enforce a periodic condition. This has the effect of changing the normals vector for projection from outward to inward facing
Default:False
C++ Type:bool
Description:Whether this constraint is going to be used to enforce a periodic condition. This has the effect of changing the normals vector for projection from outward to inward facing
- 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
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.
- variableThe name of the lagrange multiplier variable that this constraint is applied to. This parameter may not be supplied in the case of using penalty methods for example
C++ Type:NonlinearVariableName
Description:The name of the lagrange multiplier variable that this constraint is applied to. This parameter may not be supplied in the case of using penalty methods for example
Optional Parameters
- control_tagsAdds user-defined labels for accessing object parameters via control logic.
C++ Type:std::vector<std::string>
Description:Adds user-defined labels for accessing object parameters via control logic.
- enableTrueSet the enabled status of the MooseObject.
Default:True
C++ Type:bool
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
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
Description:The seed for the master random number generator
- use_displaced_meshTrueWhether 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:True
C++ Type:bool
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.
Advanced Parameters
- extra_matrix_tagsThe extra tags for the matrices this Kernel should fill
C++ Type:std::vector<TagName>
Description:The extra tags for the matrices this Kernel should fill
- extra_vector_tagsThe extra tags for the vectors this Kernel should fill
C++ Type:std::vector<TagName>
Description:The extra tags for the vectors this Kernel should fill
- matrix_tagssystemThe tag for the matrices this Kernel should fill
Default:system
C++ Type:MultiMooseEnum
Description:The tag for the matrices this Kernel should fill
- vector_tagsnontimeThe tag for the vectors this Kernel should fill
Default:nontime
C++ Type:MultiMooseEnum
Description:The tag for the vectors this Kernel should fill
Tagging Parameters
References
- Markus Gitterle, Alexander Popp, Michael W Gee, and Wolfgang A Wall.
Finite deformation frictional mortar contact using a semi-smooth newton method with consistent linearization.
International Journal for Numerical Methods in Engineering, 84(5):543–571, 2010.[BibTeX]