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updated tutorial 3: WIP #291

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131 changes: 88 additions & 43 deletions docs/tutorials.rst
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Original file line number Diff line number Diff line change
Expand Up @@ -666,10 +666,15 @@ imported from stem.additional_processes and RandomFieldGenerator is imported fro
In this step, the geometry, conditions, and material parameters for the simulation are defined.
Firstly the dimension of the model is indicated which in this case is 3. After which the model can be initialised.

In this tutorial we are going to consider two stages:
1. The first stage is the static analysis with the train model on the track.
2. The second stage is the dynamic analysis with the train model running along the track.


.. code-block:: python

ndim = 3
model = Model(ndim)
model_stage1 = Model(ndim)

# END CODE BLOCK

Expand Down Expand Up @@ -758,7 +763,7 @@ length is 50 m in the z-direction.
soil1_coordinates = [(0.0, 0.0, 0.0), (5.0, 0.0, 0.0), (5.0, 1.0, 0.0), (0.0, 1.0, 0.0)]
soil2_coordinates = [(0.0, 1.0, 0.0), (5.0, 1.0, 0.0), (5.0, 2.0, 0.0), (0.0, 2.0, 0.0)]
embankment_coordinates = [(0.0, 2.0, 0.0), (3.0, 2.0, 0.0), (1.5, 3.0, 0.0), (0.75, 3.0, 0.0), (0, 3.0, 0.0)]
model.extrusion_length = 50
model_stage1.extrusion_length = 50

# END CODE BLOCK

Expand All @@ -774,9 +779,9 @@ a unique name.

.. code-block:: python

model.add_soil_layer_by_coordinates(soil1_coordinates, material_soil_1, "soil_layer_1")
model.add_soil_layer_by_coordinates(soil2_coordinates, material_soil_2, "soil_layer_2")
model.add_soil_layer_by_coordinates(embankment_coordinates, material_embankment, "embankment_layer")
model_stage1.add_soil_layer_by_coordinates(soil1_coordinates, material_soil_1, "soil_layer_1")
model_stage1.add_soil_layer_by_coordinates(soil2_coordinates, material_soil_2, "soil_layer_2")
model_stage1.add_soil_layer_by_coordinates(embankment_coordinates, material_embankment, "embankment_layer")

# END CODE BLOCK

Expand Down Expand Up @@ -808,10 +813,10 @@ are spaced 0.5m from each others which results in a 50m straight track, with par
sleeper_spacing = 0.5
rail_pad_thickness = 0.025

model.generate_straight_track(sleeper_spacing, number_of_sleepers, rail_parameters,
sleeper_parameters, rail_pad_parameters,
rail_pad_thickness, origin_point,
direction_vector, "rail_track_1")
model_stage1.generate_straight_track(sleeper_spacing, number_of_sleepers, rail_parameters,
sleeper_parameters, rail_pad_parameters,
rail_pad_thickness, origin_point,
direction_vector, "rail_track_1")

# END CODE BLOCK

Expand Down Expand Up @@ -868,17 +873,17 @@ The following parameters can be defined in this tutorial:
NODAL_ROTATIONAL_DAMPING_COEFFICIENT=[0, 0, 0])

# create a straight track with rails, sleepers, rail pads and a 1D soil extension
model.generate_extended_straight_track(sleeper_distance=sleeper_spacing,
n_sleepers=number_of_sleepers,
rail_parameters=rail_parameters,
sleeper_parameters=sleeper_parameters,
rail_pad_parameters=rail_pad_parameters,
rail_pad_thickness=rail_pad_thickness,
origin_point=origin_point,
soil_equivalent_parameters=soil_equivalent_parameters,
length_soil_equivalent_element=length_soil_equivalent_element,
direction_vector=direction_vector,
name="rail_track_1")
model_stage1.generate_extended_straight_track(sleeper_distance=sleeper_spacing,
n_sleepers=number_of_sleepers,
rail_parameters=rail_parameters,
sleeper_parameters=sleeper_parameters,
rail_pad_parameters=rail_pad_parameters,
rail_pad_thickness=rail_pad_thickness,
origin_point=origin_point,
soil_equivalent_parameters=soil_equivalent_parameters,
length_soil_equivalent_element=length_soil_equivalent_element,
direction_vector=direction_vector,
name="rail_track_1")

# END CODE BLOCK

Expand All @@ -899,6 +904,7 @@ needs to provide the `uvec_file` and `uvec_function_name` as parameters in the U
path to the UVEC model file and the `uvec_function_name` is the name of the function in the UVEC model file.
The UVEC model file should be copied to the input files directory.

Because we are in stage 1, which is static, we set the `uvec_parameters["static_initialisation"]` to `True`.
A schematisation of the UVEC model as defined in this tutorial, is shown below.

.. image:: _static/figure_uvec.png
Expand All @@ -923,17 +929,17 @@ Below the uvec parameters are defined.
"gravity_axis": 1, # axis on which gravity works [x =0, y = 1, z = 2]
"contact_coefficient": 9.1e-7, # Hertzian contact coefficient between the wheel and the rail [N/m]
"contact_power": 1.0, # Hertzian contact power between the wheel and the rail [-]
"static_initialisation": False, # True if the analysis of the UVEC is static
"static_initialisation": True, # True if the analysis of the UVEC is static
}

# define the UVEC load
uvec_load = UvecLoad(direction=[1, 1, 1], velocity=40, origin=[0.75, 3+rail_pad_thickness, 5],
uvec_load = UvecLoad(direction=[1, 1, 1], velocity=0, origin=[0.75, 3+rail_pad_thickness, 5],
wheel_configuration=[0.0, 2.5, 19.9, 22.4],
uvec_model=uvec,
uvec_parameters=uvec_parameters)

# add the load on the tracks
model.add_load_on_line_model_part("rail_track_1", uvec_load, "train_load")
model_stage1.add_load_on_line_model_part("rail_track_1", uvec_load, "train_load")

# END CODE BLOCK

Expand Down Expand Up @@ -963,7 +969,7 @@ The mean of the property is automatically obtained from the material property al
field_generator=random_field_generator
)
# add the random field to the model
model.add_field(part_name="soil_layer_2", field_parameters=field_parameters_json)
model_stage1.add_field(part_name="soil_layer_2", field_parameters=field_parameters_json)

# END CODE BLOCK

Expand All @@ -980,7 +986,7 @@ should be set to "True".

.. code-block:: python

model.show_geometry(show_surface_ids=True)
model_stage1.show_geometry(show_surface_ids=True)

# END CODE BLOCK

Expand All @@ -1000,17 +1006,17 @@ surface-dimension, "2".
absorbing_boundaries_parameters = AbsorbingBoundary(absorbing_factors=[1.0, 1.0], virtual_thickness=40.0)


model.add_boundary_condition_by_geometry_ids(2, [1], no_displacement_parameters, "base_fixed")
model.add_boundary_condition_by_geometry_ids(2, [4, 10], roller_displacement_parameters, "sides_roller")
model.add_boundary_condition_by_geometry_ids(2, [2, 5, 6, 7, 11, 12, 15, 16, 17], absorbing_boundaries_parameters, "abs")
model_stage1.add_boundary_condition_by_geometry_ids(2, [1], no_displacement_parameters, "base_fixed")
model_stage1.add_boundary_condition_by_geometry_ids(2, [4, 10], roller_displacement_parameters, "sides_roller")
model_stage1.add_boundary_condition_by_geometry_ids(2, [2, 5, 6, 7, 11, 12, 15, 16, 17], absorbing_boundaries_parameters, "abs")

# END CODE BLOCK

After which the mesh size can be set. The mesh will be generated when the Stem class is initialised.

.. code-block:: python

model.set_mesh_size(element_size=1.0)
model_stage1.set_mesh_size(element_size=1.0)

# END CODE BLOCK

Expand All @@ -1031,16 +1037,16 @@ assumed, with a damping coefficient of 0.12 for the stiffness matrix and 0.0001

.. code-block:: python

end_time = 0.2
end_time = 10e-03
delta_time = 1e-03
analysis_type = AnalysisType.MECHANICAL
solution_type = SolutionType.DYNAMIC
solution_type = SolutionType.QUASI_STATIC

time_integration = TimeIntegration(start_time=0.0, end_time=end_time, delta_time=delta_time,
reduction_factor=1, increase_factor=1, max_delta_time_factor=1000)

convergence_criterion = DisplacementConvergenceCriteria(displacement_relative_tolerance=1.0e-4,
displacement_absolute_tolerance=1.0e-12)
displacement_absolute_tolerance=1.0e-12)

strategy_type = NewtonRaphsonStrategy()
scheme_type = NewmarkScheme()
Expand All @@ -1052,8 +1058,7 @@ assumed, with a damping coefficient of 0.12 for the stiffness matrix and 0.0001
is_stiffness_matrix_constant=True, are_mass_and_damping_constant=True,
convergence_criteria=convergence_criterion,
strategy_type=strategy_type, scheme=scheme_type,
linear_solver_settings=linear_solver_settings, rayleigh_k=0.12,
rayleigh_m=0.0001)
linear_solver_settings=linear_solver_settings)

# END CODE BLOCK

Expand All @@ -1065,7 +1070,7 @@ Now the problem data should be set up. The problem should be given a name, in th
# Set up problem data
problem = Problem(problem_name="calculate_uvec_on_embankment_with_absorbing_boundaries", number_of_threads=4,
settings=solver_settings)
model.project_parameters = problem
model_stage1.project_parameters = problem

# END CODE BLOCK

Expand All @@ -1086,7 +1091,7 @@ type is set to "step", meaning that the results will be written every time step.

.. code-block:: python

model.add_output_settings(
model_stage1.add_output_settings(
part_name="porous_computational_model_part",
output_dir=results_dir,
output_name="vtk_output",
Expand Down Expand Up @@ -1115,7 +1120,7 @@ the calculation time step `delta_time` is required.
(5, 2.0, 25.0)
]

model.add_output_settings_by_coordinates(
model_stage1.add_output_settings_by_coordinates(
part_name="subset_outputs",
output_dir=results_dir,
output_name="json_output",
Expand All @@ -1135,24 +1140,64 @@ calling the `Model.show_geometry` method.

.. code-block:: python

model.show_geometry()
model_stage1.show_geometry()

# END CODE BLOCK

Now that the model is set up, the calculation is almost ready to be run.
Now we need to assing stage 1 to the STEM model.


.. code-block:: python

stem = Stem(model_stage1, input_files_dir)

# END CODE BLOCK

Firstly the Stem class is initialised, with the model and the directory where the input files will be written to.
While initialising the Stem class, the mesh will be generated.

Once the initial stage is build we can add a second stage which correponds to the moving vehicle.
First we start by creating a new stage:

.. code-block:: python

stem = Stem(model, input_files_dir)
time_step = 1e-3
end_time = 0.2
model_stage2 = stem.create_new_stage(delta_time=time_step, stage_duration=end_time)

# END CODE BLOCK

The Kratos input files are then written. The project settings and output definitions are written to
ProjectParameters_stage_1.json file. The mesh is written to the .mdpa file and the material parameters are
written to the MaterialParameters_stage_1.json file.
Now we need to redefine the UVEC model, since the train is moving in the second stage. In this case the train will
travel at 40m/s.



.. code-block:: python

model_stage2.get_model_part_by_name("train_load").parameters.velocity = 40.0

# END CODE BLOCK

To perform a dynamic analysis the settings of the stage 2 need to be updated, in particular the solution type
and the rayleigh damping coefficients.

.. code-block:: python

model_stage2.project_parameters.settings.solution_type = SolutionType.DYNAMIC
model_stage2.project_parameters.settings.rayleigh_k = 0.001
model_stage2.project_parameters.settings.rayleigh_m = 0.01

# END CODE BLOCK

The stage two needs to be added to the calculation:

.. code-block:: python

stem.add_calculation_stage(model_stage2)

# END CODE BLOCK

The Kratos input files are then written. The project settings and output definitions are written to files.
All of the input files are then written to the input files directory.

.. code-block:: python
Expand Down