Ratel I43_09 elastoplastic cylinder - Quasi-static Implicit

This study investigates micromorphic upscaling of a heterogeneous material composed of grains and a binder. The DNS is an inelastic, implicit finite element (FE) model assuming quasi-static conditions conducted in Ratel. The results of this DNS are prepared for the Micromorphic Filter for a variety of filtering domains. Filter output is then used to calibrate an elastic micromorphic material model which is implemented for simulation in Tardigrade-MOOSE. Unique material calibrations are produced for each filtering domain which are prescribed to their corresponding elements in the macroscale simulations.

A variety of simulation variables are provided in the I43_best_DNS dictionary in the model_package/DNS_Ratel/simulation_variables_nominal.py file. This dictionary is loaded into the workflow as the params dictionary.

 1I43_best_DNS = {
 2    # DNS parameters
 3    'diam': 5.034722222222221,
 4    'height': 4.553571428571429,
 5    'center': [2.529673695728830, 2.529673695728830, 2.200488433837890],
 6    'material_E': 250.0,
 7    'material_nu': 0.25,
 8    'cut': True,
 9    # Mesh file root to copy if Cubit is not found
10    'mesh_copy_root': 'Ratel_I43_09',
11    # parameters for micromorphic filter
12    'acceleration': False,
13    'velocity': False,
14    'filter_parallel': 8,
15    'homogenize_damage': True,
16    # parameters for elastic calibration
17    'elastic_calibration_case': 8,
18    'plastic_calibration_case': 6,
19    'softening_plastic_calibration_case': 10,
20    'calibration_increment_elastic': [0, 1, 2, 3],
21    'calibration_increment_plastic': [4, 5, 6, 7, 8, 9, 10, 11, 12],
22    'calibration_increment_softening': [3, 5, 7, 9, 10, 11, 12, 13, 14, 15, 16],
23    # parameters for plastic calibration
24    'cohesion_case': 1,
25    'cohesion_increment': [3, 4, 5],
26    # paramters for Tardigrade-MOOSE
27    'macro_disp': 0.220, #timestep for Monitor_000124.vtu
28    'macro_duration': 1.0,
29    'macro_BC': 'slip_plane',
30}

Warning

The DNS files needed for this upscaling study can only be access by users with a CU Boulder identikey and access to the PetaLibrary!

DNS files are copied from the PetaLibrary into a local directory “peta_data_copy” using the following command. This command usually only needs to be used once. Files are copied using the secure copy protocal (SCP). A user will be asked for their identikey, password, and two factor authentication (2FA).

$ scons --peta-data-copy

The analysis is executed in individual stages by the Ratel_I43_09_multi_domain_best_DNS SConscript. First, the existing DNS results are processed into the required XDMF file format for the Micromorphic Filter using the following command:

$ scons Ratel_I43_09_multi_domain_best_DNS

Next the homogenization is performed. Macroscale meshes with 1, 24, 48, 264, 768, and 2160 elements are considered for the default configuration. The micromorphic filter is parallelized to run on 8 cpus. This value may be modified by changing the value of “filter_parallel” in the I43_best_DNS parameter dictionary.

$ scons Ratel_I43_09_multi_domain_best_DNS --filter

Calibration is then performed for each macroscale element (i.e. filtering domain). This process can be rather expensive depending on what model is being calibrated, however, WAVES provides a simple way to parallelize the independent calibration processes using the --jobs=N command line option. Calibration may be performed using a single process or multiple (10 in this example) with either of the following two options. Parameter sets 0 through 5 correspond to the macroscale meshes with 1, 24, 48, 264, 768, and 2160 elements. One may choose to only calibrate parameter sets 0, 1, and 2 using the --selected-parameter-sets command line option.

$ scons Ratel_I43_09_multi_domain_best_DNS --calibrate
$ scons Ratel_I43_09_multi_domain_best_DNS --calibrate --jobs=10
$ scons Ratel_I43_09_multi_domain_best_DNS --calibrate --jobs=10 --selected-parameter-sets='0 1 2'

Once calibration is completed, Tardigrade-MOOSE simulations may be performed. A Tardigrade-MOOSE simulation is performed for each case of filtering domains. Macroscale simulations may be parallelized using the --solve-cpu=N command line option. Macroscale simulations may be performed using a single process or multiple (12 in the example) below. There are three different types of macroscale simulations that may specified:

  • The --macro command line option will run simulations with clamped boundary conditions

  • The --macro-platen command line option will run simulations with loading platens

  • The --macro-damage command line option will run simulations using gradient-enhanced damage plasticity if Tardigrade-MOOSE is configured properly.

DNS Description and Results

Discussion coming soon

Filter Preparation

Discussion coming soon

Filter Results

Discussion coming soon

Micromorphic Constitutive Model Calibration

Discussion coming soon

Macroscale Simulation

Discussion coming soon