A geometric generation tool for prismatic cellular solids
Project description
RingsPy
RingsPy is a Voronoi diagrams-based geometric generation tool that generates 3D meshes and models of prismatic cellular solids with radial growth rules.
Dependencies and Installation
1. pip install
To install RingsPy, one may use:
pip install RingsPy
or use:
pip install git+https://github.com/kingyin3613/RingsPy.git
to get updates beyond the latest release.
RingsPy depends on mainstream Python libraries numpy
and scipy
, and optionally depends on library hexalattice
, if the regular hexagonal lattice (e.g. honeycomb) is wanted; also vtk
, if the 3D STL files are also wanted.
2. Installation check
There are some unit tests in tests. You can use pytest
to check whether the installation is successful by running this command:
pytest .
Getting Started
Once all required components are installed and one is ready to begin, a path forward should be established for generating the mesh. The basic steps for running/viewing a cellular mesh are listed as the following:
1. Edit geometry and algorithm parameters
2. Generate mesh using Mesh Generation Tools
3. Visualize 2D view using Matplotlib or 3D model in Paraview
4. (Optional) Export 3D STL model for 3D editing and/or printing
1. Geometry and Parameters
The first step to generate a cellular geometry is selecting geometry and appropriate parameters.
1.1. Geometry
A template file, test_wood_cube.py
located in the tests directory acts as both the parameter input file, and main executable for the generation of a cubic wood specimen.
Note: The Mesh Generation Tool by now only accepts many of pre-defined boundary geometries, importing of CAD and/or other 3D model files will be implemented in subsequent versions.
Note: for greatest compatibility create the geometry using all millimeters.
1.2. Parameters
By opening a input file, such as tests/test_wood_cube.py
in any text editor, a file format similar to what is shown below will be displayed:
geoName = 'wood_cube'
path = 'meshes'
iter_max = 100
print_interval = 500
# length unit: mm
r_min = 0 # inner radius of wood log
r_max = 4 # outer radius of wood log
nrings = 4 # number of rings
width_heart = 0.3*(r_max-r_min)/nrings # heart wood ring width
width_early = 0.7*(r_max-r_min)/nrings # early wood ring width
width_late = 0.3*(r_max-r_min)/nrings # late wood ring width
log_center = (0,0) # coordinates of log center in the global system of reference
box_center = (1.25,0) # coordinates of box center in the global system of reference
box_size = 1.0 # cube size
# if precracked
x_indent_size = box_size*0.120
y_indent_size = box_size*0.125
x_precrack_size = box_size*0.1
y_precrack_size = box_size*0.02
x_indent = x_min + x_indent_size
y_indent_min = box_center[1] - y_indent_size/2
y_indent_max = box_center[1] + y_indent_size/2
x_precrack = x_indent + x_precrack_size
y_precrack = box_center[1]
cellsize_early = 0.02
cellsize_late = 0.01
cellwallthickness_early = 0.010
cellwallthickness_late = 0.006
merge_operation = 'off'
merge_tol = 0.01
precrackFlag = 'off'
precrack_widths = 0.1
boundaryFlag = 'on'
stlFlag = 'on'
geoName
is the geometry name,path
is the folder where the mesh files will be generated.iter_max
is the max number of iteration for randomly placing a new non-overlapping wood cell particle in the 2D annual rings domain. Generally, largeriter_max
leads to more centroidal Voronoi cells, for more reference, see Centroidal Voronoi Tessellation.print_interval
is the print interval when every n cell particles are placed in the model domain.r_min
andr_max
are the upper and lower bounds of radii to generate 2D annual rings,nrings
is the number of rings.width_heart
,width_early
, andwidth_late
, are annual ring widths for heartwood, earlywood, and latewood, respectively, which all together determine the morphology of the wood mesostructure.log_center
,box_center
, andbox_size
are for locating the wood log and cutting box._indent
,_precrack
parameters are related to precracked sample generation, which will be added in the next version.cellsize_early
,cellsize_late
,cellwallthickness_early
, andcellwallthickness_late
are parameters for the earlywood and latewood cells.merge_operation
flag can be turned on/off for the merging operation, when turned on, all small wood cell ridges shorter than the thresholdmerge_tol
will be merged with neighboring ridges.precrackFlag
flag is for inserting a pre-crack, for the notched specimens. So far, only a single line pre-crack with the length ofprecrack_widths
is supported.boundaryFlag
flag can be turned on/off for generating neat boundaries consisting of grains.stlFlag
flag can be turned on/off for generating 3D STL files.
2.1. Run Mesh Generation
Open a Command Prompt or Terminal window and set the current directory to tests or any other directory, then run the command:
python test_wood_cube.py
Functions in MeshGenTools
library will be called to create the initial mesh, wood cell particles following certain cell size distribution will be placed, then Scipy.voronoi
function will be called to form the initial 2D Voronoi tessellation, additional code reforms the tesselation and generates the desired files. A successful generation will end with the line "Files generated ..." in the Terminal window.
A new folder should have been created in the .\meshes
directory with the same name as the geoName
in test_wood_cube.py
.
2.2. Check Mesh and 3D Model Files
The following files should be generated in the .\meshes\geoName
directory with a successful run:
- Mesh files
- Non-Uniform Rational B-Splines (NURBS) beam file:
wood_cubeIGA.txt
- connector data file:
wood_cube-mesh.txt
- Grain-ridge data file:
wood_cube-vertex.mesh
- Ridge data file:
wood_cube-ridge.mesh
- Non-Uniform Rational B-Splines (NURBS) beam file:
- Visualization files
- Paraview vtk file for initial vertex configuration:
wood_cube_vertices.vtu
- Paraview vtk file for initial grain solid configuration:
wood_cube_beams.vtu
- Paraview vtk file of initial cell ridge configuration:
wood_cube_conns.vtu
- Paraview vtk file of initial connector (volume) configuration:
wood_cube_conns_vol.vtu
- Paraview vtk file for initial vertex configuration:
- (Optional) 3D model files
- STL file of initial cellular solid configuration:
wood_cube.stl
- STL file of initial cellular solid configuration:
3. Visualization
A scientific visualization application ParaView
can directly visualize the generated vtk files; It can also visualize generated 3D model STL files if the STL flag is on. The Paraview software can be downloaded from their official website: https://www.paraview.org/download/, latest version is recommeded.
3.1. Visualize the components of the 3D model in ParaView
1. Open ParaView
2. Recommeded to temporarily turn off ray tracing
- Uncheck "Enable Ray Tracing" (bottom left)
3. Open File Sets in `.\meshes\geoName`
- File > Open...
4. Select the visualization files containing: `_vertices.vtu`, `_beams.vtu`, `_conns.vtu`
5. Apply to visualize
- Press Apply (left side, center)
6. Turn on color plotting
- Left click `_conns.vtu`, then select coloring (mid/lower left) > Connector_width
7. Scale and position the image as desired
8. Turn back on Ray Tracing
9. Adjust Ray Tracing lighting and settings as desired
10. Export Image
- File > Save Screenshot
- Enter a file name > OK
- Leave new window as-is or increase resolution > OK
3.2. Visualize the volumes of the 3D model in ParaView
1. Open Paraview
2. Recommeded to temporarily turn off ray tracing
- Uncheck "Enable Ray Tracing" (bottom left)
3. Open File Sets in `.\meshes\geoName`
- File > Open...
4. Select the newly created visualization files containing: `_conns_vol.vtu`
5. Apply to visualize
- Press Apply (left side, center)
6. Turn on color plotting
- Left click `_conns_vol.vtu`, then select coloring (mid/lower left) > Connector_width
7. Scale and position the image as desired
8. Turn back on Ray Tracing
9. Adjust Ray Tracing lighting and settings as desired
10. Export Image
- File > Save Screenshot
- Enter a file name > OK
- Leave new window as-is or increase resolution > OK
Contributing
Contributions are always welcome!
If you wish to contribute code/algorithms to this project, or to propose a collaboration study, please send an email to haoyin2022 [at] u.northwestern.edu .
License
Distributed under the GPL v3 license. Copyright 2022 Hao Yin.
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