dynakw 1.0.0

LS-DYNA Keywords Reader Library

LS-DYNA™ Keyword Reader (dynakw)

A Python library for reading, parsing, editing, and writing LS-DYNA keyword files.

The library is designed to scale by incorporating LS-DYNA documentation and keyword examples, using prompt examples from the documentation. The maintenance and expansion of the library is automated by supplying this information to AI coding agents.

Status

Currently implemented:

• *BOUNDARY_PRESCRIBED_MOTION
• *ELEMENT_SHELL
• *ELEMENT_SOLID
• *MAT_ELASTIC
• *NODE
• *PART
• *SECTION_SHELL
• *SECTION_SOLID

The other keywords are preserved as raw text and type unknown. They can be written out unchanged, allowing any deck to be edited.

Usage

To read a file and print the keywords:

import sys
from dynakw import DynaKeywordReader, KeywordType

with DynaKeywordReader('lsdyna_exa.k') as dkr:

    # to access all keywords
    for kw in dkr.keywords():
        kw.write(sys.stdout)

    # reading a specific keyword
    for kw in dkr.find_keywords(KeywordType.NODE):
        kw.write(sys.stdout)

    # The edited file can be saved: 
    dkr.write('exa2.k')

A keywords have a type and a cards member. The values inside the cards member are dictionaries containing the data stored as numpy arrays following the LS-DYNA documentation. For example, a scale factor can be changed as follows:

if kw.type == KeywordType.BOUNDARY_PRESCRIBED_MOTION:
    kw.cards['Card 1']['SF'] = kw.cards['Card 1']['SF'] * 1.5

See also the code in the examples directory for more usage.

Example problems

The example problems demonstrate:

• Printing the content of an LS-DYNA input deck.
• Editing an LS-DYNA input deck.
• Displaying the mesh using PyVista.
• Converting LS-DYNA input to Radioss input.

More documentation

See the docs directory.

Contributing

Contributions are welcome! You can contribute either keywords examples for the QA or enhancements to the code reading the keywords.

This is easily done using AI coding agents considering the relevant LS-DYNA keyword chapter, an example keyword deck, and the existing code.

Adding a keyword using the Gemnini CLI

See .gemini/commands/*.toml for the prompts and the GEMINI.md files for an explanation of the code structure. Use the following slash commands:

\generate_instructions SECTION_SPH
\implement_keyword SECTION_SPH
\update_qa

Manually adding a new keyword

To add a keyword manually:

1. Add the new keyword to the KeywordType enum in dynakw/core/enums.py.
2. Create a new Python file in the dynakw/keywords/ directory named after the keyword.
3. Implement the keyword class, inheriting from LSDynaKeyword and providing the _parse_raw_data and write methods.
4. The unit tests should work for your new keyword (they use the enum from step 1). This requires that the keyword be present in test/full_files/*.k.

Contributing LS-DYNA keyword examples

If you have LS-DYNA input decks, please consider contributing them as examples. This helps ensure the quality and correctness of the library. A contribution can be as small as a single keyword definition. Contributing a keyword is how you ensure that it will always be read correctly by the library.

The keywords should be added to the test/full_files/ directory.

Having many keyword contributions is important because LS-DYNA has evolved to accomodate many variations of the keywords.

Testing

The code in the test directory can be exercised using 'python3 run_tests.py'. This step is essential in a new checkout because it create test data from the keyword contributions.

The '\update_qa' slash command can be used to update the tests.

Trademarks and related

LS-DYNA™ is a registered trademark of ANSYS Inc.

LS-DYNA examples can be downloaded at https://www.dynaexamples.com/ . This is currently free of charge, please see the instructions on the website, specifically the home page.

License

This project is licensed under the MIT License.