ComputeFrictionalForceCartesianLMMechanicalContact

Computes mortar frictional forces.

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:

Ctj(λj,u,u˙)=max(μ(p+cng~nj),abs(λj+ctu~tj))λjμmax(0,(p+cng~nj))(λj+ctu~tj)C_{tj}(\lambda_{j},\boldsymbol{u}, \boldsymbol{\dot{u}}) = \max({\mu({p} + c_{n}\tilde{g}_{nj}), \mathrm{abs}({\lambda_{j} + c_t \tilde{u}_{tj}})) \lambda_{j} - \mu \max({0,({p} + c_{n}\tilde{g}_{nj})}) (\lambda_{j} + c_t \tilde{u}_{tj}) }

pp is the normal contact pressure, λj\lambda_{j} is a Lagrange's multiplier that refers to the tangential contact pressure at node jj, u~tj\tilde{u}_{tj} is the weighted tangential velocity integrated forward in time, g~n)j\tilde{g}_n)_j is the weighted normal gap, cnc_{n} is a numerical parameter (cc in ComputeWeightedGapLMMechanicalContact) and ctc_{t} is a numerical parameter that can determine convergence properties but has no effect on the results.

The nodal, weighted tangential velocity is computed as v~tj=γc(1)Φjvt,hdA\tilde{v}_{tj} = \int_{\gamma_c^{(1)}} \Phi_j v_{t,h} dA

where γc(1)\gamma_c^{(1)} denotes the secondary contact interface, Φj\Phi_j is the j'th lagrange multiplier test function, and vt,hv_{t,h} is the discretized version of the tangential velocity function. Note that this object assumes that the Lagrange multipliers are defined in a global Cartesian frame. Local variables to solve the contact problem are projected using nodal geometry, i.e. normal and tangential vectors.

This object automatically enforces normal contact constraints by making calls to its parent class.

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.

The ComputeFrictionalForceCartesianLMMechanicalContact object computes the weighted gap and applies the frictional contact conditions using Lagrange multipliers defined in a global Cartesian reference frame. As a consequence, the number of contact constraints at each node will be two, in two-dimensional problems, and three, in three-dimensional problems. The normal contact pressure is obtained by projecting the Lagrange multiplier vector along the normal vector computed from the mortar generation objects. The result is a normal contact constraint, which, in general, will be a function of all (two or three) Cartesian Lagrange multipliers. The other degree(s) of freedom are constrained by enforcing that tangential tractions follow Coulomb constraints within a semi-smooth Newton approach. Usage of Cartesian Lagrange multipliers is recommended when condensing Lagrange multipliers via the variable condensation preconditioner (VCP) VariableCondensationPreconditioner.

Input Parameters

  • disp_xThe x displacement variable

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The x displacement variable

  • disp_yThe y displacement variable

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The y displacement variable

  • lm_xMechanical contact Lagrange multiplier along the x Cartesian axis

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:Mechanical contact Lagrange multiplier along the x Cartesian axis

  • lm_yMechanical contact Lagrange multiplier along the y Cartesian axis.

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:Mechanical contact Lagrange multiplier along the y Cartesian axis.

  • primary_boundaryThe name of the primary boundary sideset.

    C++ Type:BoundaryName

    Controllable:No

    Description:The name of the primary boundary sideset.

  • primary_subdomainThe name of the primary subdomain.

    C++ Type:SubdomainName

    Controllable:No

    Description:The name of the primary subdomain.

  • secondary_boundaryThe name of the secondary boundary sideset.

    C++ Type:BoundaryName

    Controllable:No

    Description:The name of the secondary boundary sideset.

  • secondary_subdomainThe name of the secondary subdomain.

    C++ Type:SubdomainName

    Controllable:No

    Description:The name of the secondary subdomain.

Required Parameters

  • aux_lmAuxiliary Lagrange multiplier variable that is utilized together with the Petrov-Galerkin approach.

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:Auxiliary Lagrange multiplier variable that is utilized together with the Petrov-Galerkin approach.

  • c1e+06Parameter for balancing the size of the gap and contact pressure

    Default:1e+06

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Parameter for balancing the size of the gap and contact pressure

  • c_t1Numerical parameter for tangential constraints

    Default:1

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Numerical parameter for tangential constraints

  • compute_lm_residualsTrueWhether to compute Lagrange Multiplier residuals

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether to compute Lagrange Multiplier residuals

  • compute_primal_residualsTrueWhether to compute residuals for the primal variable.

    Default:True

    C++ Type:bool

    Controllable:No

    Description:Whether to compute residuals for the primal variable.

  • correct_edge_droppingFalseWhether to enable correct edge dropping treatment for mortar constraints. When disabled any Lagrange Multiplier degree of freedom on a secondary element without full primary contributions will be set (strongly) to 0.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether to enable correct edge dropping treatment for mortar constraints. When disabled any Lagrange Multiplier degree of freedom on a secondary element without full primary contributions will be set (strongly) to 0.

  • debug_meshFalseWhether this constraint is going to enable mortar segment mesh debug information. An exodusfile will be generated if the user sets this flag to true

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether this constraint is going to enable mortar segment mesh debug information. An exodusfile will be generated if the user sets this flag to true

  • disp_zThe z displacement variable

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:The z displacement variable

  • epsilon1e-07Minimum value of contact pressure that will trigger frictional enforcement

    Default:1e-07

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Minimum value of contact pressure that will trigger frictional enforcement

  • ghost_higher_d_neighborsFalseWhether we should ghost higher-dimensional neighbors. This is necessary when we are doing second order mortar with finite volume primal variables, because in order for the method to be second order we must use cell gradients, which couples in the neighbor cells.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether we should ghost higher-dimensional neighbors. This is necessary when we are doing second order mortar with finite volume primal variables, because in order for the method to be second order we must use cell gradients, which couples in the neighbor cells.

  • ghost_point_neighborsFalseWhether we should ghost point neighbors of secondary face elements, and consequently also their mortar interface couples.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether we should ghost point neighbors of secondary face elements, and consequently also their mortar interface couples.

  • interpolate_normalsFalseWhether 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:False

    C++ Type:bool

    Controllable:No

    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

  • lm_zMechanical contact Lagrange multiplier along the z Cartesian axis.

    C++ Type:std::vector<VariableName>

    Unit:(no unit assumed)

    Controllable:No

    Description:Mechanical contact Lagrange multiplier along the z Cartesian axis.

  • matrix_onlyFalseWhether this object is only doing assembly to matrices (no vectors)

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether this object is only doing assembly to matrices (no vectors)

  • minimum_projection_angle40Parameter to control which angle (in degrees) is admissible for the creation of mortar segments. If set to a value close to zero, very oblique projections are allowed, which can result in mortar segments solving physics not meaningfully, and overprojection of primary nodes onto the mortar segment mesh in extreme cases. This parameter is mostly intended for mortar mesh debugging purposes in two dimensions.

    Default:40

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:Parameter to control which angle (in degrees) is admissible for the creation of mortar segments. If set to a value close to zero, very oblique projections are allowed, which can result in mortar segments solving physics not meaningfully, and overprojection of primary nodes onto the mortar segment mesh in extreme cases. This parameter is mostly intended for mortar mesh debugging purposes in two dimensions.

  • muThe friction coefficient for the Coulomb friction law

    C++ Type:double

    Unit:(no unit assumed)

    Controllable:No

    Description:The friction coefficient for the Coulomb friction law

  • normalize_cFalseWhether to normalize c by weighting function norm. When unnormalized the value of c effectively depends on element size since in the constraint we compare nodal Lagrange Multiplier values to integrated gap values (LM nodal value is independent of element size, where integrated values are dependent on element size).

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether to normalize c by weighting function norm. When unnormalized the value of c effectively depends on element size since in the constraint we compare nodal Lagrange Multiplier values to integrated gap values (LM nodal value is independent of element size, where integrated values are dependent on element size).

  • 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

    Controllable:No

    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

  • quadratureDEFAULTQuadrature rule to use on mortar segments. For 2D mortar DEFAULT is recommended. For 3D mortar, QUAD meshes are integrated using triangle mortar segments. While DEFAULT quadrature order is typically sufficiently accurate, exact integration of QUAD mortar faces requires SECOND order quadrature for FIRST variables and FOURTH order quadrature for SECOND order variables.

    Default:DEFAULT

    C++ Type:MooseEnum

    Options:DEFAULT, FIRST, SECOND, THIRD, FOURTH

    Controllable:No

    Description:Quadrature rule to use on mortar segments. For 2D mortar DEFAULT is recommended. For 3D mortar, QUAD meshes are integrated using triangle mortar segments. While DEFAULT quadrature order is typically sufficiently accurate, exact integration of QUAD mortar faces requires SECOND order quadrature for FIRST variables and FOURTH order quadrature for SECOND order variables.

  • use_petrov_galerkinFalseWhether to use the Petrov-Galerkin approach for the mortar-based constraints. If set to true, we use the standard basis as the test function and dual basis as the shape function for the interpolation of the Lagrange multiplier variable.

    Default:False

    C++ Type:bool

    Controllable:No

    Description:Whether to use the Petrov-Galerkin approach for the mortar-based constraints. If set to true, we use the standard basis as the test function and dual basis as the shape function for the interpolation of the Lagrange multiplier variable.

  • 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

    Unit:(no unit assumed)

    Controllable:No

    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

  • absolute_value_vector_tagsThe tags for the vectors this residual object should fill with the absolute value of the residual contribution

    C++ Type:std::vector<TagName>

    Controllable:No

    Description:The tags for the vectors this residual object should fill with the absolute value of the residual contribution

  • extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

    C++ Type:std::vector<TagName>

    Controllable:No

    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>

    Controllable:No

    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

    Options:nontime, system

    Controllable:No

    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

    Options:nontime, time

    Controllable:No

    Description:The tag for the vectors this Kernel should fill

Contribution To Tagged Field Data 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_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

    Controllable:No

    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

  • 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

    Unit:(no unit assumed)

    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.

  • 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.

Material Property Retrieval Parameters

Input Files

References

  1. 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]