- solve_typeconsistentThe way to solve the system. A 'consistent' solve uses the full mass matrix and actually needs to use a linear solver to solve the problem. 'lumped' uses a lumped mass matrix with a simple inversion - incredibly fast but may be less accurate. 'lump_preconditioned' uses the lumped mass matrix as a preconditioner for the 'consistent' solve
Default:consistent
C++ Type:MooseEnum
Controllable:No
Description:The way to solve the system. A 'consistent' solve uses the full mass matrix and actually needs to use a linear solver to solve the problem. 'lumped' uses a lumped mass matrix with a simple inversion - incredibly fast but may be less accurate. 'lump_preconditioned' uses the lumped mass matrix as a preconditioner for the 'consistent' solve
- use_constant_massFalseIf set to true, will only compute the mass matrix in the first time step, and keep using it throughout the simulation.
Default:False
C++ Type:bool
Controllable:No
Description:If set to true, will only compute the mass matrix in the first time step, and keep using it throughout the simulation.
CentralDifference
Implementation of explicit, Central Difference integration without invoking any of the nonlinear solver
Description
Central difference integration is a common explicit integration scheme, typically used in structural dynamics. For a variable, , at time with a time step, , the central difference approximations for the first and second time derivatives, and , are given as,
The central difference time integrator derives from the ActuallyExplicitEuler class and therefore circumvents the nonlinear solver. It can be used with consistent, lumped or lump_preconditioned, solve_type options. Information on these solve options can be found on the ActuallyExplicitEuler page.
Input 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:No
Description:Set the enabled status of the MooseObject.
Advanced Parameters
Input Files
- (modules/tensor_mechanics/test/tests/central_difference/lumped/2D/2d_lumped_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/lumped/1D/1d_lumped_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/lumped/3D/3d_lumped_explicit.i)
- (test/tests/time_integrators/central-difference/ad_central_difference_dotdot.i)
- (modules/tensor_mechanics/test/tests/central_difference/lumped/3D/3d_nodalmass_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/consistent/1D/1d_consistent_explicit.i)
- (test/tests/time_integrators/central-difference/central_difference.i)
- (modules/tensor_mechanics/test/tests/central_difference/lumped/2D/2d_nodalmass_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/lumped/1D/1d_nodalmass_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/consistent/2D/2d_consistent_explicit.i)
- (modules/tensor_mechanics/test/tests/central_difference/consistent/3D/3d_consistent_explicit.i)
(modules/tensor_mechanics/test/tests/central_difference/lumped/2D/2d_lumped_explicit.i)
# Tests for the central difference time integrator for 2D elements
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
dim = 2
xmin = 0
xmax = 1
ymin = 0
ymax = 2
nx = 1
ny = 2
[../]
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[]
[AuxVariables]
[./accel_x]
[../]
[./vel_x]
[../]
[./accel_y]
[../]
[./vel_y]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_y
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[./inertia_y]
type = InertialForce
variable = disp_y
[../]
[]
[BCs]
[./y_bot]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0.0
[../]
[./x_bot]
type = FunctionDirichletBC
boundary = bottom
variable = disp_x
function = disp
preset = false
[../]
[]
[Functions]
[./disp]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 1e4
[../]
[]
[Executioner]
type = Transient
start_time = 0
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
solve_type = lumped
[../]
[]
[Postprocessors]
[./accel_2x]
type = PointValue
point = '1.0 2.0 0.0'
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/lumped/1D/1d_lumped_explicit.i)
# Test for central difference integration for a 1D element
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
xmin = 0
xmax = 10
nx = 5
dim = 1
[../]
[]
[Variables]
[./disp_x]
[../]
[]
[AuxVariables]
[./accel_x]
[../]
[./vel_x]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[]
[NodalKernels]
[./force_x]
type = UserForcingFunctionNodalKernel
variable = disp_x
boundary = right
function = force_x
[../]
[]
[Functions]
[./force_x]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # force
scale_factor = 1e3
[../]
[]
[BCs]
[./fixx1]
type = DirichletBC
variable = disp_x
boundary = left
value = 0.0
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 2500
[../]
[]
[Executioner]
type = Transient
start_time = -0.01
end_time = 0.1
timestep_tolerance = 2e-10
dt = 0.005
[./TimeIntegrator]
type = CentralDifference
solve_type = lumped
[../]
[]
[Postprocessors]
[./accel_x]
type = PointValue
point = '10.0 0.0 0.0'
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/lumped/3D/3d_lumped_explicit.i)
# Test for the central difference time integrator in 3D.
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
dim = 3
nx = 1
ny = 1
nz = 2
xmin = 0.0
xmax = 1
ymin = 0.0
ymax = 1
zmin = 0.0
zmax = 2
[../]
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[./disp_z]
[../]
[]
[AuxVariables]
[./vel_x]
[../]
[./accel_x]
[../]
[./vel_y]
[../]
[./accel_y]
[../]
[./vel_z]
[../]
[./accel_z]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_x
[../]
[./accel_z]
type = TestNewmarkTI
variable = accel_z
displacement = disp_z
first = false
[../]
[./vel_z]
type = TestNewmarkTI
variable = vel_z
displacement = disp_z
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y disp_z'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[./inertia_y]
type = InertialForce
variable = disp_y
[../]
[./inertia_z]
type = InertialForce
variable = disp_z
[../]
[]
[BCs]
[./x_bot]
type = FunctionDirichletBC
variable = disp_x
boundary = 'back'
function = dispx
preset = false
[../]
[./y_bot]
type = FunctionDirichletBC
variable = disp_y
boundary = 'back'
function = dispy
preset = false
[../]
[./z_bot]
type = FunctionDirichletBC
variable = disp_z
boundary = 'back'
function = dispz
preset = false
[../]
[]
[Functions]
[./dispx]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[./dispy]
type = ParsedFunction
value = 0.1*t*t*sin(10*t)
[../]
[./dispz]
type = ParsedFunction
value = 0.1*t*t*sin(20*t)
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y disp_z'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 1e4
[../]
[]
[Executioner]
type = Transient
start_time = -0.01
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
solve_type = lumped
[../]
[]
[Postprocessors]
[./accel_10x]
type = NodalVariableValue
nodeid = 10
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(test/tests/time_integrators/central-difference/ad_central_difference_dotdot.i)
###########################################################
# This is a simple test with a time-dependent problem
# demonstrating the use of the TimeIntegrator system.
#
# Testing that the second time derivative is calculated
# correctly using the Central Difference method for an AD
# variable.
#
###########################################################
[Mesh]
type = GeneratedMesh
dim = 2
xmin = -1
xmax = 1
ymin = -1
ymax = 1
nx = 1
ny = 1
[]
[Variables]
[./u]
[../]
[]
[Functions]
[./forcing_fn]
type = PiecewiseLinear
x = '0.0 0.1 0.2 0.3 0.4 0.5 0.6'
y = '0.0 0.0 0.0025 0.01 0.0175 0.02 0.02'
[../]
[]
[Kernels]
[./ie]
type = ADTimeDerivative
variable = u
[../]
[./diff]
type = ADDiffusion
variable = u
[../]
[]
[BCs]
[./left]
type = ADFunctionDirichletBC
variable = u
boundary = 'left'
function = forcing_fn
preset = false
[../]
[./right]
type = ADFunctionDirichletBC
variable = u
boundary = 'right'
function = forcing_fn
preset = false
[../]
[]
[Executioner]
type = Transient
[./TimeIntegrator]
type = CentralDifference
[]
start_time = 0.0
num_steps = 6
dt = 0.1
[]
[Postprocessors]
[./udotdot]
type = ElementAverageSecondTimeDerivative
variable = u
[../]
[]
[Outputs]
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/lumped/3D/3d_nodalmass_explicit.i)
# Test for the CentralDifference time integrator
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
dim = 3
nx = 1
ny = 1
nz = 2
xmin = 0.0
xmax = 1
ymin = 0.0
ymax = 1
zmin = 0.0
zmax = 2
[../]
[./all_nodes]
type = BoundingBoxNodeSetGenerator
new_boundary = 'all'
input = 'generated_mesh'
top_right = '1 1 2'
bottom_left = '0 0 0'
[../]
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[./disp_z]
[../]
[]
[AuxVariables]
[./vel_x]
[../]
[./accel_x]
[../]
[./vel_y]
[../]
[./accel_y]
[../]
[./vel_z]
[../]
[./accel_z]
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y disp_z'
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_y
[../]
[./accel_z]
type = TestNewmarkTI
variable = accel_z
displacement = disp_z
first = false
[../]
[./vel_z]
type = TestNewmarkTI
variable = vel_z
displacement = disp_z
[../]
[]
[BCs]
[./x_bot]
type = FunctionDirichletBC
boundary = 'back'
variable = disp_x
function = dispx
preset = false
[../]
[./y_bot]
type = FunctionDirichletBC
variable = disp_y
boundary = back
function = dispy
preset = false
[../]
[./z_bot]
type = FunctionDirichletBC
variable = disp_z
boundary = back
function = dispz
preset = false
[../]
[]
[Functions]
[./dispx]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[./dispy]
type = ParsedFunction
value = 0.1*t*t*sin(10*t)
[../]
[./dispz]
type = ParsedFunction
value = 0.1*t*t*sin(20*t)
[../]
[]
[NodalKernels]
[./nodal_mass_x]
type = NodalTranslationalInertia
boundary = 'all'
nodal_mass_file = 'nodal_mass_file.csv'
variable = 'disp_x'
[../]
[./nodal_mass_y]
type = NodalTranslationalInertia
boundary = 'all'
nodal_mass_file = 'nodal_mass_file.csv'
variable = 'disp_y'
[../]
[./nodal_mass_z]
type = NodalTranslationalInertia
boundary = 'all'
nodal_mass_file = 'nodal_mass_file.csv'
variable = 'disp_z'
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y disp_z'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[]
[Executioner]
type = Transient
start_time = -0.01
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./accel_10x]
type = NodalVariableValue
nodeid = 10
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/consistent/1D/1d_consistent_explicit.i)
# Test for central difference integration for a 1D element
# Consistent mass matrix
[Mesh]
type = GeneratedMesh
xmin = 0
xmax = 10
nx = 5
dim = 1
[]
[Variables]
[./disp_x]
order = FIRST
family = LAGRANGE
[../]
[]
[AuxVariables]
[./accel_x]
[../]
[./vel_x]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[]
[NodalKernels]
[./force_x]
type = UserForcingFunctionNodalKernel
variable = disp_x
boundary = right
function = force_x
[../]
[]
[Functions]
[./force_x]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # force
scale_factor = 1e3
[../]
[]
[BCs]
[./fixx1]
type = DirichletBC
variable = disp_x
boundary = left
value = 0.0
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 2500
[../]
[]
[Executioner]
type = Transient
start_time = -0.005
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
l_tol = 1e-10
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./disp_x]
type = NodalVariableValue
nodeid = 1
variable = disp_x
[../]
[./vel_x]
type = NodalVariableValue
nodeid = 1
variable = vel_x
[../]
[./accel_x]
type = NodalVariableValue
nodeid = 1
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
perf_graph = false
[]
(test/tests/time_integrators/central-difference/central_difference.i)
###########################################################
# This is a simple test with a time-dependent problem
# demonstrating the use of the TimeIntegrator system.
#
# Testing that the first and second time derivatives
# are calculated correctly using the Central Difference
# method
#
# @Requirement F1.30
###########################################################
[Mesh]
type = GeneratedMesh
dim = 2
xmin = -1
xmax = 1
ymin = -1
ymax = 1
nx = 1
ny = 1
[]
[Variables]
[./u]
[../]
[]
[Functions]
[./forcing_fn]
type = PiecewiseLinear
x = '0.0 0.1 0.2 0.3 0.4 0.5 0.6'
y = '0.0 0.0 0.0025 0.01 0.0175 0.02 0.02'
[../]
[]
[Kernels]
[./ie]
type = TimeDerivative
variable = u
[../]
[./diff]
type = Diffusion
variable = u
[../]
[]
[BCs]
[./left]
type = FunctionDirichletBC
variable = u
boundary = 'left'
function = forcing_fn
preset = false
[../]
[./right]
type = FunctionDirichletBC
variable = u
boundary = 'right'
function = forcing_fn
preset = false
[../]
[]
[Executioner]
type = Transient
[./TimeIntegrator]
type = CentralDifference
[]
start_time = 0.0
num_steps = 6
dt = 0.1
[]
[Postprocessors]
[./udot]
type = ElementAverageTimeDerivative
variable = u
[../]
[./udotdot]
type = ElementAverageSecondTimeDerivative
variable = u
[../]
[./u]
type = ElementAverageValue
variable = u
[../]
[]
[Outputs]
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/lumped/2D/2d_nodalmass_explicit.i)
# One element test to test the central difference time integrator.
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
dim = 2
xmin = 0
xmax = 1
ymin = 0
ymax = 2
nx = 1
ny = 2
[../]
[./all_nodes]
type = BoundingBoxNodeSetGenerator
new_boundary = 'all'
input = 'generated_mesh'
top_right = '1 2 0'
bottom_left = '0 0 0'
[../]
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[]
[AuxVariables]
[./accel_x]
[../]
[./vel_x]
[../]
[./accel_y]
[../]
[./vel_y]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_y
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y'
[../]
[]
[BCs]
[./y_bot]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0.0
[../]
[./x_bot]
type = FunctionDirichletBC
boundary = bottom
variable = disp_x
function = disp
preset = false
[../]
[]
[Functions]
[./disp]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[]
[NodalKernels]
[./nodal_mass_x]
type = NodalTranslationalInertia
variable = 'disp_x'
nodal_mass_file = 'nodal_mass_file.csv'
boundary = 'all'
[../]
[./nodal_mass_y]
type = NodalTranslationalInertia
variable = 'disp_y'
nodal_mass_file = 'nodal_mass_file.csv'
boundary = 'all'
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[]
[Executioner]
type = Transient
start_time = 0
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./accel_2x]
type = PointValue
point = '1.0 2.0 0.0'
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/lumped/1D/1d_nodalmass_explicit.i)
# Test for central difference integration for 1D elements
[Mesh]
[./generated_mesh]
type = GeneratedMeshGenerator
xmin = 0
xmax = 10
nx = 5
dim = 1
[../]
[./all_nodes]
type = BoundingBoxNodeSetGenerator
new_boundary = 'all'
input = 'generated_mesh'
top_right = '10 0 0'
bottom_left = '0 0 0'
[../]
[]
[Variables]
[./disp_x]
[../]
[]
[AuxVariables]
[./accel_x]
[../]
[./vel_x]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x'
[../]
[]
[NodalKernels]
[./force_x]
type = UserForcingFunctionNodalKernel
variable = disp_x
boundary = right
function = force_x
[../]
[./nodal_masses]
type = NodalTranslationalInertia
nodal_mass_file = 'nodal_mass_file.csv'
variable = 'disp_x'
boundary = 'all'
[../]
[]
[Functions]
[./force_x]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # force
scale_factor = 1e3
[../]
[]
[BCs]
[./fixx1]
type = DirichletBC
variable = disp_x
boundary = left
value = 0.0
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[]
[Executioner]
type = Transient
start_time = -0.01
end_time = 0.1
dt = 0.005
timestep_tolerance = 2e-10
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./accel_x]
type = PointValue
point = '10.0 0.0 0.0'
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/consistent/2D/2d_consistent_explicit.i)
# Test for the central difference time integrator for a 2D mesh
[Mesh]
type = GeneratedMesh
dim = 2
nx = 1
ny = 2
xmin = 0.0
xmax = 1.0
ymin = 0.0
ymax = 2.0
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[]
[AuxVariables]
[./vel_x]
[../]
[./accel_x]
[../]
[./vel_y]
[../]
[./accel_y]
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[./inertia_y]
type = InertialForce
variable = disp_y
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_y
[../]
[]
[BCs]
[./y_bot]
type = DirichletBC
variable = disp_y
boundary = bottom
value = 0.0
[../]
[./x_bot]
type = FunctionDirichletBC
boundary = bottom
variable = disp_x
function = disp
preset = false
[../]
[]
[Functions]
[./disp]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 1e4
[../]
[]
[Executioner]
type = Transient
start_time = 0
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./_dt]
type = TimestepSize
[../]
[./accel_2x]
type = PointValue
point = '1.0 2.0 0.0'
variable = accel_x
[../]
[./accel_2y]
type = PointValue
point = '1.0 2.0 0.0'
variable = accel_y
[../]
[]
[Outputs]
exodus = false
csv = true
[]
(modules/tensor_mechanics/test/tests/central_difference/consistent/3D/3d_consistent_explicit.i)
# One element test to test the central difference time integrator in 3D.
[Mesh]
type = GeneratedMesh
dim = 3
nx = 1
ny = 1
nz = 2
xmin = 0.0
xmax = 1
ymin = 0.0
ymax = 1
zmin = 0.0
zmax = 2
[]
[Variables]
[./disp_x]
[../]
[./disp_y]
[../]
[./disp_z]
[../]
[]
[AuxVariables]
[./vel_x]
[../]
[./accel_x]
[../]
[./vel_y]
[../]
[./accel_y]
[../]
[./vel_z]
[../]
[./accel_z]
[../]
[]
[AuxKernels]
[./accel_x]
type = TestNewmarkTI
variable = accel_x
displacement = disp_x
first = false
[../]
[./vel_x]
type = TestNewmarkTI
variable = vel_x
displacement = disp_x
[../]
[./accel_y]
type = TestNewmarkTI
variable = accel_y
displacement = disp_y
first = false
[../]
[./vel_y]
type = TestNewmarkTI
variable = vel_y
displacement = disp_x
[../]
[./accel_z]
type = TestNewmarkTI
variable = accel_z
displacement = disp_z
first = false
[../]
[./vel_z]
type = TestNewmarkTI
variable = vel_z
displacement = disp_z
[../]
[]
[Kernels]
[./DynamicTensorMechanics]
displacements = 'disp_x disp_y disp_z'
[../]
[./inertia_x]
type = InertialForce
variable = disp_x
[../]
[./inertia_y]
type = InertialForce
variable = disp_y
[../]
[./inertia_z]
type = InertialForce
variable = disp_z
[../]
[]
[BCs]
[./x_bot]
type = FunctionDirichletBC
variable = disp_x
boundary = 'back'
function = dispx
preset = false
[../]
[./y_bot]
type = FunctionDirichletBC
variable = disp_y
boundary = 'back'
function = dispy
preset = false
[../]
[./z_bot]
type = FunctionDirichletBC
variable = disp_z
boundary = 'back'
function = dispz
preset = false
[../]
[./Periodic]
[./x_dir]
variable = 'disp_x disp_y disp_z'
primary = 'left'
secondary = 'right'
translation = '1.0 0.0 0.0'
[../]
[./y_dir]
variable = 'disp_x disp_y disp_z'
primary = 'bottom'
secondary = 'top'
translation = '0.0 1.0 0.0'
[../]
[../]
[]
[Functions]
[./dispx]
type = PiecewiseLinear
x = '0.0 1.0 2.0 3.0 4.0' # time
y = '0.0 1.0 0.0 -1.0 0.0' # displacement
[../]
[./dispy]
type = ParsedFunction
value = 0.1*t*t*sin(10*t)
[../]
[./dispz]
type = ParsedFunction
value = 0.1*t*t*sin(20*t)
[../]
[]
[Materials]
[./elasticity_tensor_block]
type = ComputeIsotropicElasticityTensor
youngs_modulus = 1e6
poissons_ratio = 0.25
block = 0
[../]
[./strain_block]
type = ComputeIncrementalSmallStrain
block = 0
displacements = 'disp_x disp_y disp_z'
implicit = false
[../]
[./stress_block]
type = ComputeFiniteStrainElasticStress
block = 0
[../]
[./density]
type = GenericConstantMaterial
block = 0
prop_names = density
prop_values = 1e4
[../]
[]
[Executioner]
type = Transient
start_time = -0.01
end_time = 0.1
dt = 0.005
timestep_tolerance = 1e-6
[./TimeIntegrator]
type = CentralDifference
[../]
[]
[Postprocessors]
[./accel_6x]
type = NodalVariableValue
nodeid = 6
variable = accel_x
[../]
[]
[Outputs]
exodus = false
csv = true
[]