PresetAcceleration

Prescribe acceleration on a given boundary in a given direction

The PresetAcceleration class takes an acceleration time history (provided using a function) as input and converts the acceleration into displacement using Newmark time integration method. This displacement is then prescribed at the user provided boundary in the direction corresponding to the displacement variable provided as input.

Input Parameters

accelerationThe acceleration variable.
C++ Type:std::vector
Options:
Description:The acceleration variable.
betabeta parameter for Newmark time integration.
C++ Type:double
Options:
Description:beta parameter for Newmark time integration.
boundaryThe list of boundary IDs from the mesh where this boundary condition applies
C++ Type:std::vector
Options:
Description:The list of boundary IDs from the mesh where this boundary condition applies
variableThe name of the variable that this boundary condition applies to
C++ Type:NonlinearVariableName
Options:
Description:The name of the variable that this boundary condition applies to
velocityThe velocity variable.
C++ Type:std::vector
Options:
Description:The velocity variable.

Required Parameters

diag_save_inThe name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this BC's diagonal jacobian contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
displacementsThe displacements
C++ Type:std::vector
Options:
Description:The displacements
function1Function describing the velocity.
Default:1
C++ Type:FunctionName
Options:
Description:Function describing the velocity.
save_inThe name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
C++ Type:std::vector
Options:
Description:The name of auxiliary variables to save this BC's residual contributions to. Everything about that variable must match everything about this variable (the type, what blocks it's on, etc.)
scale_factor1Scale factor if function is given.
Default:1
C++ Type:double
Options:
Description:Scale factor if function is given.

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.
implicitTrueDetermines whether this object is calculated using an implicit or explicit form
Default:True
C++ Type:bool
Options:
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
Options:
Description:The seed for the master random number generator
use_displaced_meshFalseWhether 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:False
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_tagssystem timeThe tag for the matrices this Kernel should fill
Default:system time
C++ Type:MultiMooseEnum
Options:nontime system time
Description:The tag for the matrices this Kernel should fill
vector_tagsresidualThe tag for the vectors this Kernel should fill
Default:residual
C++ Type:MultiMooseEnum
Options:nontime time residual
Description:The tag for the vectors this Kernel should fill

Tagging Parameters

Input Files

modules/tensor_mechanics/test/tests/dynamics/acceleration_bc/AccelerationBC_test.i
modules/tensor_mechanics/test/tests/dynamics/acceleration_bc/AccelerationBC_test_ti.i

modules/tensor_mechanics/test/tests/dynamics/acceleration_bc/AccelerationBC_test.i

# Test for  Acceleration boundary condition

# This test contains one brick element which is fixed in the y and z direction.
# Base acceleration is applied in the x direction to all nodes on the bottom surface (y=0).

# The PresetAcceleration converts the given acceleration to a displacement
# using Newmark time integration. This displacement is then prescribed on the boundary.
#
# Result: The acceleration at the bottom node should be same as the input acceleration
# which is a triangular function with peak at t = 0.2 in this case. Width of the triangular function
# is 0.2 s.

[Mesh]
  type = GeneratedMesh
  dim = 3
  nx = 1
  ny = 1
  nz = 1
  xmin = 0.0
  xmax = 0.1
  ymin = 0.0
  ymax = 1.0
  zmin = 0.0
  zmax = 0.1
[]

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
  [./disp_z]
  [../]
[]

[AuxVariables]
  [./vel_x]
  [../]
  [./accel_x]
  [../]
  [./vel_y]
  [../]
  [./accel_y]
  [../]
  [./vel_z]
  [../]
  [./accel_z]
  [../]
  [./stress_yy]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./strain_yy]
    order = CONSTANT
    family = MONOMIAL
  [../]

[]

[Kernels]
  [./TensorMechanics]
  [../]
  [./inertia_x]
    type = InertialForce
    variable = disp_x
    velocity = vel_x
    acceleration = accel_x
    beta = 0.25
    gamma = 0.5
  [../]
  [./inertia_y]
    type = InertialForce
    variable = disp_y
    velocity = vel_y
    acceleration = accel_y
    beta = 0.25
    gamma = 0.5
  [../]
  [./inertia_z]
    type = InertialForce
    variable = disp_z
    velocity = vel_z
    acceleration = accel_z
    beta = 0.25
    gamma = 0.5
  [../]

[]

[AuxKernels]
  [./accel_x]
    type = NewmarkAccelAux
    variable = accel_x
    displacement = disp_x
    velocity = vel_x
    beta = 0.25
    execute_on = timestep_end
  [../]
  [./vel_x]
    type = NewmarkVelAux
    variable = vel_x
    acceleration = accel_x
    gamma = 0.5
    execute_on = timestep_end
  [../]
  [./accel_y]
    type = NewmarkAccelAux
    variable = accel_y
    displacement = disp_y
    velocity = vel_y
    beta = 0.25
    execute_on = timestep_end
  [../]
  [./vel_y]
    type = NewmarkVelAux
    variable = vel_y
    acceleration = accel_y
    gamma = 0.5
    execute_on = timestep_end
  [../]
  [./accel_z]
    type = NewmarkAccelAux
    variable = accel_z
    displacement = disp_z
    velocity = vel_z
    beta = 0.25
    execute_on = timestep_end
  [../]
  [./vel_z]
    type = NewmarkVelAux
    variable = vel_z
    acceleration = accel_z
    gamma = 0.5
    execute_on = timestep_end
  [../]
  [./stress_yy]
    type = RankTwoAux
    rank_two_tensor = stress
    variable = stress_yy
    index_i = 0
    index_j = 1
  [../]
  [./strain_yy]
    type = RankTwoAux
    rank_two_tensor = total_strain
    variable = strain_yy
    index_i = 0
    index_j = 1
  [../]

[]

[Functions]
  [./acceleration_bottom]
    type = PiecewiseLinear
    data_file = acceleration.csv
    format = columns
  [../]
[]

[BCs]
  [./top_y]
    type = DirichletBC
    variable = disp_y
    boundary = top
    value=0.0
  [../]
  [./top_z]
    type = DirichletBC
    variable = disp_z
    boundary = top
    value=0.0
  [../]
  [./bottom_y]
    type = DirichletBC
    variable = disp_y
    boundary = bottom
    value=0.0
  [../]
  [./bottom_z]
    type = DirichletBC
    variable = disp_z
    boundary = bottom
    value=0.0
  [../]
  [./preset_accelertion]
    type = PresetAcceleration
    boundary = bottom
    function = acceleration_bottom
    variable = disp_x
    beta = 0.25
    acceleration = accel_x
    velocity = vel_x
   [../]
[]

[Materials]
  [./Elasticity_tensor]
    type = ComputeElasticityTensor
    fill_method = symmetric_isotropic
    C_ijkl = '210e9 0'
  [../]

  [./strain]
    type = ComputeSmallStrain
  [../]

  [./stress]
    type = ComputeLinearElasticStress
  [../]
  [./density]
    type = GenericConstantMaterial
    prop_names = 'density'
    prop_values = '7750'
  [../]

[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart'
  petsc_options_value = 'hypre    boomeramg      101'
  start_time = 0
  end_time = 2.0
  dt = 0.01
  dtmin = 0.01
  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-8
  l_tol = 1e-8
  timestep_tolerance = 1e-8
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
  [./disp]
    type = NodalVariableValue
    variable = disp_x
    nodeid = 1
  [../]
  [./vel]
    type = NodalVariableValue
    variable = vel_x
    nodeid = 1
  [../]
  [./accel]
    type = NodalVariableValue
    variable = accel_x
    nodeid = 1
  [../]
[]

[Outputs]
  csv = true
  exodus = true
  perf_graph = true
[]

modules/tensor_mechanics/test/tests/dynamics/acceleration_bc/AccelerationBC_test_ti.i

# Test for  Acceleration boundary condition

# This test contains one brick element which is fixed in the y and z direction.
# Base acceleration is applied in the x direction to all nodes on the bottom surface (y=0).

# The PresetAcceleration converts the given acceleration to a displacement
# using Newmark time integration. This displacement is then prescribed on the boundary.
#
# Result: The acceleration at the bottom node should be same as the input acceleration
# which is a triangular function with peak at t = 0.2 in this case. Width of the triangular function
# is 0.2 s.

[Mesh]
  type = GeneratedMesh
  dim = 3
  nx = 1
  ny = 1
  nz = 1
  xmin = 0.0
  xmax = 0.1
  ymin = 0.0
  ymax = 1.0
  zmin = 0.0
  zmax = 0.1
[]

[GlobalParams]
  displacements = 'disp_x disp_y disp_z'
[]

[Variables]
  [./disp_x]
  [../]
  [./disp_y]
  [../]
  [./disp_z]
  [../]
[]

[AuxVariables]
  [./vel_x]
  [../]
  [./accel_x]
  [../]
  [./vel_y]
  [../]
  [./accel_y]
  [../]
  [./vel_z]
  [../]
  [./accel_z]
  [../]
  [./stress_yy]
    order = CONSTANT
    family = MONOMIAL
  [../]
  [./strain_yy]
    order = CONSTANT
    family = MONOMIAL
  [../]

[]

[Kernels]
  [./TensorMechanics]
  [../]
  [./inertia_x]
    type = InertialForce
    variable = disp_x
  [../]
  [./inertia_y]
    type = InertialForce
    variable = disp_y
  [../]
  [./inertia_z]
    type = InertialForce
    variable = disp_z
  [../]

[]

[AuxKernels]
  [./accel_x] # These auxkernels are only to check output
    type = TestNewmarkTI
    displacement = disp_x
    variable = accel_x
    first = false
  [../]
  [./accel_y]
    type = TestNewmarkTI
    displacement = disp_y
    variable = accel_y
    first = false
  [../]
  [./accel_z]
    type = TestNewmarkTI
    displacement = disp_z
    variable = accel_z
    first = false
  [../]
  [./vel_x]
    type = TestNewmarkTI
    displacement = disp_x
    variable = vel_x
  [../]
  [./vel_y]
    type = TestNewmarkTI
    displacement = disp_y
    variable = vel_y
  [../]
  [./vel_z]
    type = TestNewmarkTI
    displacement = disp_z
    variable = vel_z
  [../]
  [./stress_yy]
    type = RankTwoAux
    rank_two_tensor = stress
    variable = stress_yy
    index_i = 0
    index_j = 1
  [../]
  [./strain_yy]
    type = RankTwoAux
    rank_two_tensor = total_strain
    variable = strain_yy
    index_i = 0
    index_j = 1
  [../]

[]

[Functions]
  [./acceleration_bottom]
    type = PiecewiseLinear
    data_file = acceleration.csv
    format = columns
  [../]
[]

[BCs]
  [./top_y]
    type = DirichletBC
    variable = disp_y
    boundary = top
    value=0.0
  [../]
  [./top_z]
    type = DirichletBC
    variable = disp_z
    boundary = top
    value=0.0
  [../]
  [./bottom_y]
    type = DirichletBC
    variable = disp_y
    boundary = bottom
    value=0.0
  [../]
  [./bottom_z]
    type = DirichletBC
    variable = disp_z
    boundary = bottom
    value=0.0
  [../]
  [./preset_accelertion]
    type = PresetAcceleration
    boundary = bottom
    function = acceleration_bottom
    variable = disp_x
    beta = 0.25
    acceleration = accel_x
    velocity = vel_x
   [../]
[]

[Materials]
  [./Elasticity_tensor]
    type = ComputeElasticityTensor
    fill_method = symmetric_isotropic
    C_ijkl = '210e9 0'
  [../]

  [./strain]
    type = ComputeSmallStrain
  [../]

  [./stress]
    type = ComputeLinearElasticStress
  [../]
  [./density]
    type = GenericConstantMaterial
    prop_names = 'density'
    prop_values = '7750'
  [../]

[]

[Executioner]
  type = Transient
  solve_type = 'PJFNK'
  petsc_options_iname = '-pc_type -pc_hypre_type -ksp_gmres_restart'
  petsc_options_value = 'hypre    boomeramg      101'
  start_time = 0
  end_time = 2.0
  dt = 0.01
  dtmin = 0.01
  nl_abs_tol = 1e-8
  nl_rel_tol = 1e-8
  l_tol = 1e-8
  timestep_tolerance = 1e-8

  # Time integrator scheme
  schem = "newmark-beta"
[]

[Postprocessors]
  [./_dt]
    type = TimestepSize
  [../]
  [./disp]
    type = NodalVariableValue
    variable = disp_x
    nodeid = 1
  [../]
  [./vel]
    type = NodalVariableValue
    variable = vel_x
    nodeid = 1
  [../]
  [./accel]
    type = NodalVariableValue
    variable = accel_x
    nodeid = 1
  [../]
[]

[Outputs]
  file_base = "AccelerationBC_test_out"
  csv = true
  exodus = true
  perf_graph = true
[]

References

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Input Files
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