Create model from imported mesh#

OpenFDEM supports users to import standard mesh files such as .inp files, .msh files, and .geo files to run the model. This example will review how to setup a uniaxial compressive test example with output from Gmsh software.

Runtime: < 10 min on i9 8-core Windows 10 Machine

Expected tutorial output (visualized in ParaView):

UCS Example Image

Note

OpenFDEM supports four main mesh pre-processing approaches:

  1. A user defined command in OpenFDEM to create mesh automatically

  2. Importing a .geo file

  3. Importing a .msh file

  4. Mesh developed from other commercial softwares, including .inp, .dxf, .fdem, .tess (for grain-based model only) and .jpg (for grain-based module and DFN module only).

1 Tutorial Prerequistes#

The following files are needed to follow along the tutorial:

2 Codes#

1. OpenFDEM supports various common mesh file format such as .inp files, .msh files, and .geo files. In this example, “Job-3.inp” file in the folder will be imported to the model, which has the same mesh as the first unconfined compression test example.

of.import "Job-3.inp"

  1. Given input file was exported from ABAQUS without assigning groups, so users need to group elements manually here.

of.group.element 'up' range box.in [-35e-3 35e-3  50e-3  55e-3] 
of.group.element 'rock' range box.in [-35e-3 35e-3 -50e-3  50e-3]
of.group.element 'down' range box.in [-35e-3 35e-3  -55e-3  -50e-3]

3 Full Script#

# initialization, this command is to clear the memory in your last run, it is not 
# mandatory but strongly recommend.
of.new

# Set the path folder of your output results, //result// in the same path of your input 
# file will be created by default
of.set.result "result"

# Set the interval of logging in the log file, 2000 is by default, not mandatory
of.log.interval 2000

# Set the number of cores you want to use, the parallization will be automatically turned 
# on when you use the following command, otherwise the serilization will be used by 
# default
of.set.omp 15

###################################### create mesh #######################################
# Openfdem supports import common mesh files such as .inp .msh .geo and others
of.import "Job-3.inp"

# Given input file was exported from ABAQUS without assigning groups, so users need to 
# group elements manually here.
of.group.element 'up' range box.in [-35e-3 35e-3  50e-3  55e-3] 
of.group.element 'rock' range box.in [-35e-3 35e-3 -50e-3  50e-3]
of.group.element 'down' range box.in [-35e-3 35e-3  -55e-3  -50e-3] 
# Insert the cohesive elements.
of.mesh.insert 'rock'

################################# assign material parameters ##############################
# Assign material for matrix.
of.mat.element 'default' elastic den 2700 E 30e9 v 0.3 damp 2.0
# Assign rigid material to the two plattens
of.mat.element 'up' rigid den 2700 
of.mat.element 'down' rigid den 2700
# assign material for CZM
of.mat.cohesive 'default' EM ten 1e6 coh 3e6 fric 0.3 GI 10 GII 50 
# assign materials for contacts
of.mat.contact 'default' MC fric 0.3

##################################### create groups #######################################
# OpenFDEM can manually group the nodes, elements, cohesive elements and edges by using the 
# region of box, circle and plane.
of.group.nodal.from.element 'up' 'up'
of.group.nodal.from.element 'down' 'down'

################################### assign boundaries #####################################
# boundaries can be assigned after you define the groups
of.boundary.nodal.velocity  'up' x 0.0 y -0.05 r 0.0
of.boundary.nodal.velocity  'down' x 0.0 y 0.05 r 0.0

####################################### set output ########################################
# Set the interval of writing ParaView results.
of.history.pv.interval 5000
# Output all results by default.
of.history.pv.field default
of.history.pv.fracture default

##################################### execute model #######################################
# Manually set the timestep to overwirte the default timestep suggested by the program.
# It is not recommended to manually increase the size of timesteps unless the user has 
# enough understanding of the calculation process.
of.timestep fix 5e-9
# to excuate the model
of.step 500000
# finalize the model and clear the memory
of.finalize