PolyGen: An Efficient Framework for Polycrystal Generation and Cohesive Zone Modeling in Arbitrary Domains

This project aims to generalize polycrystal generation and polygonal meshing in any arbitrary 2D domains through Constrained Voronoi Tessellation for Finite Element Method (FEM) and Cohesive Zone Modeling (CZM). PolyGen also provides the functionality to adjust polygonal mesh to insert finite-thickness cohesive zone and offers efficient datastructures to integrate with Abaqus CAE. Additionally, this package also offers an excellent tool for triangular meshing of complex 2D domains.

Features

• Introduces a comprehensive framework for generating polycrystalline grain structures in arbitrary 2D domains.
• Enables seamless insertion of both zero-thickness and finite-thickness cohesive zones for interface modeling.
• Provides efficient datastructures for integration with Abaqus CAE
• Provides efficient mesh optimization techniques.
• Provides efficient triangular meshing framework for complex domains.
• Enable high-quality visualisation and saving of meshfiles into various formats supported by meshio.

Installation

To install the package, use pip:

cd polygen
pip install -e .

Accessing Documentation

To access the documentation for any function, class, or method in the project, please visit the official documentation page of PolyGen View the Docs

Example Usage

Check out the detailed examples and usages of different functionalities in the PolyGen Jupyter Notebook.

Running polygen from the command line

If you have set up the input file with the desired functionalites, you can run the following command in the terminal (assuming your input file is in the examples directory inside your working directory):

polygen -d2 ./examples/input.in

Example Input File (input.in)

The input.in file should contain the necessary inputs for running the desired functions. The file should follow a simple key-value format, with each parameter on a new line. The parameters can be provided in any order.

Parameters

• boundary : str or dict The path to the mesio supported mesh file defining the boundary or predefined geometry object provided by PolyGen
• N_points : int Number of initial seed points for the Voronoi diagram
• points_seed : int, optional Random seed for generating initial Poisson disk sampling points (default: 42)
• margin : float, optional Margin to add around the boundary for generating seed points (default: 0.01)
• N_iter : int, optional Number of iterations for Lloyd's algorithm to relax the points (default: 100000)
• use_decay : bool, optional Whether to use decay in Lloyd's algorithm (default: True)
• edgeLength_threshold : float, optional Length threshold for collapsing short edges in the Voronoi diagram (default: None)
• cohesiveThickness : float, optional Thickness of the cohesive zone for adjusting the Voronoi cells (default: None)
• triangularMesh_minLength : float, optional Minimum edge length for triangular meshing (default: None)
• visualize : bool, optional Whether to show visualization plots (default: False)
• saveData : bool, optional Whether to save the resulting data structures to files (default: True)

Here is an example of how to organize the input.in file:

# This is a comment
#boundary = Geometry.annular_region((0.0, -0.075), point_outer=(0.0, 1.49), center_inner=(0.0, -0.425), point_inner=(0.0, 0.5), name='Calcite_region360d')
boundary = ./examples/CalciteBoundaryFromPNG.obj
N_points = 1000
points_seed = 7845
margin = 0.01
N_iter = 10000000
use_decay = True
edgeLength_threshold = 6.3
cohesiveThickness = 0.02
triangularMesh_minLength = 15
visualize = True
saveData = True

Citation

If you use PolyGen in your research, please cite our paper:

Rumi, M.J.U., Han, HC., Ye, J. et al. Polygen: an efficient framework for polycrystals generation and cohesive zone modeling in arbitrary domains. Engineering with Computers (2025). https://doi.org/10.1007/s00366-025-02180-6

BibTeX

@article{rumi2025polygen,
  title={Polygen: an efficient framework for polycrystals generation and cohesive zone modeling in arbitrary domains},
  author={Rumi, Md Jalal Uddin and Han, Hai-Chao and Ye, JingYong and Feldman, Marc and Gruslova, Aleksandra and Nolen, Drew and Zeng, Xiaowei},
  journal={Engineering with Computers},
  pages={1--21},
  year={2025},
  publisher={Springer}
}

License

This project is licensed under the MIT License.

Contributing

Contributions are welcome! Please fork the repository and submit a pull request with your changes.

Acknowledgements

Special thanks to all contributors and the open-source community for their valuable work and support.

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Feel free to modify and expand upon this draft to better suit your project's needs and details. This structure should give users a clear understanding of the project and how to use the various scripts.

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