NormalNodalLMMechanicalContact

The NormalNodalLMMechanicalContact class is used to ensure that the Karush-Kuhn-Tucker conditions of mechanical contact are satisfied:

where is the gap and is the contact pressure, a Lagrange multipler variable living on the slave face. This object enforces constraints nodally so that zero penetration of nodes is observed into the master face.

The ncp_function_type parameter specifies the type of nonlinear complimentarity problem (NCP) function to use. The options are either min, which is just the min function, or fb which represents the Fischer-Burmeister function. In our experience, the min function achieves better convergence in the non-linear solve. The c parameter is used to balance the size of the gap and the normal contact pressure. If the contact pressure is of order 10000, and the gap is of order .01, then c should be set to 1e6 in order to bring components of the NCP function onto the same level and achieve optimal convergence in the non-linear solve.

Implements the KKT conditions for normal contact using an NCP function. Requires that either the gap distance or the normal contact pressure (represented by the value of variable) is zero. The LM variable must be of the same order as the mesh

Input Parameters

  • masterThe boundary ID associated with the master side

    C++ Type:BoundaryName

    Options:

    Description:The boundary ID associated with the master side

  • master_variableThe variable on the master side of the domain

    C++ Type:std::vector

    Options:

    Description:The variable on the master side of the domain

  • slaveThe boundary ID associated with the slave side

    C++ Type:BoundaryName

    Options:

    Description:The boundary ID associated with the slave side

  • variableThe name of the variable that this constraint is applied to.

    C++ Type:NonlinearVariableName

    Options:

    Description:The name of the variable that this constraint is applied to.

Required Parameters

  • c1Parameter for balancing the size of the gap and contact pressure

    Default:1

    C++ Type:double

    Options:

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

  • disp_yThe y displacement

    C++ Type:std::vector

    Options:

    Description:The y displacement

  • disp_zThe z displacement

    C++ Type:std::vector

    Options:

    Description:The z displacement

  • execute_onLINEARThe list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

    Default:LINEAR

    C++ Type:ExecFlagEnum

    Options:NONE INITIAL LINEAR NONLINEAR TIMESTEP_END TIMESTEP_BEGIN FINAL CUSTOM

    Description:The list of flag(s) indicating when this object should be executed, the available options include NONE, INITIAL, LINEAR, NONLINEAR, TIMESTEP_END, TIMESTEP_BEGIN, FINAL, CUSTOM.

  • ncp_function_typeminThe type of NCP function to use

    Default:min

    C++ Type:MooseEnum

    Options:min fb

    Description:The type of NCP function to use

  • normal_smoothing_distanceDistance from edge in parametric coordinates over which to smooth contact normal

    C++ Type:double

    Options:

    Description:Distance from edge in parametric coordinates over which to smooth contact normal

  • normal_smoothing_methodMethod to use to smooth normals (edge_based|nodal_normal_based)

    C++ Type:std::string

    Options:

    Description:Method to use to smooth normals (edge_based|nodal_normal_based)

  • orderFIRSTThe finite element order used for projections

    Default:FIRST

    C++ Type:MooseEnum

    Options:FIRST SECOND THIRD FOURTH

    Description:The finite element order used for projections

  • tangential_toleranceTangential distance to extend edges of contact surfaces

    C++ Type:double

    Options:

    Description:Tangential distance to extend edges of contact surfaces

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.

  • 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

    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.

Advanced Parameters

  • extra_matrix_tagsThe extra tags for the matrices this Kernel should fill

    C++ Type:std::vector

    Options:

    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

    Options:

    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

    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

    Description:The tag for the vectors this Kernel should fill

Tagging Parameters

Input Files

References