Dirichlet Boundary Condition

The ApplyMPMParticleDirichletConditionProcess imposes non-conforming Dirichlet boundary conditions by means of the Penalty method, which is implemened by boundary material points conditions.

Parameters & Defaults

{
    "kratos_module" : "KratosMultiphysics.MPMApplication",
    "python_module" : "apply_mpm_particle_dirichlet_condition_process",
    "Parameters"    : {
        "model_part_name"                   : "PLEASE_SPECIFY_MODEL_PART_NAME",
        "material_points_per_condition"     : 0,
        "is_equal_distributed"              : false,
        "penalty_factor"                    : 0,
        "variable_name"                     : "DISPLACEMENT",
        "constrained"                       : "fixed",
        "value"                             : [0.0, "0*t", 0.0],
        "interval"                          : [0.0, 1e30],
        "option"                            : ""
    }
}

model_part_name

String identifying the name of the target ModelPart to which the boundary conditions will be applied.

material_points_per_condition

Defines the number of material point conditions used to replace each line or surface condition where Dirichlet boundary conditions must be imposed.

is_equal_distributed

If true, material point conditions are equally distributed over the original (line or surface) condition, otherwise their position is determined by Gauss quadrature nodes.

penalty_factor

Penalty coefficient used in the penalty method to enforce Dirichlet boundary conditions.

variable_name

String identifying the variable whose value is to be imposed using the Penalty method. Admissible values are:

• "DISPLACEMENT"
• "VELOCITY"
• "ACCELERATION"

constrained

Specifies the type of Dirichlet boundary condition to be imposed. Admissible values are:

• "fixed" - the variable is fully constrained
• "contact" - movement is constrained only in the case of contact with the non-conforming boundary
• "slip" - constrains the movement along the normal direction while not restricting the others
• "contact_slip" - combines both contact and slip constraints

value

Value to be assigned to the variable specified by variable_name. Each component of the list can be either a number or a string representing a function depending on space and/or time.

interval

Time interval in which the process applies.

option

If set to "flip_normal", the normal of each condition is flipped.

Source Code

MPMApplication/python_scripts/apply_mpm_particle_dirichlet_condition_process.py

Reference

Chandra, B., Singer, V., Teschemacher, T., Wuechner, R., & Larese, A. (2021). Nonconforming Dirichlet boundary conditions in implicit material point method by means of penalty augmentation, Acta Geotechnica, 16(8), 2315-2335. DOI: 10.1007/s11440-020-01123-3.