Getting Started

Introduction

abqpy is a Python package providing type hints for Python scripting of Abaqus, you can use it to write you Python script of Abaqus fluently, even without doing anything in Abaqus. It also provides some simple APIs to execute the Abaqus commands so that you can run your Python script to build the model, submit the job and extract the output data in just one Python script, even without opening the Abaqus/CAE.

Installation

Make sure and are installed on your computer before installing abqpy.

You can install abqpy with the following commands.

pip install abqpy==2023.*  # recommended
pip install abqpy==2023.5.7
pip install abqpy

# with jupyter notebook support
pip install abqpy[jupyter]==2023.*  # recommended
pip install abqpy[jupyter]==2023.5.7
pip install abqpy[jupyter]
pip install git+https://github.com/haiiliin/abqpy@2023
pip install ipynbname nbconvert  # with jupyter notebook support

Note

You are recommended to install the corresponding version of Abaqus and abqpy to avoid any compatibility issues.

Two Python interpreters

Before we go any further, it is necessary for us to understand two Python interpreters.

When we use the Abaqus/CAE graphical user interface (GUI) to create a model and to visualize the results, commands are issued internally by Abaqus/CAE after every operation. These commands reflect the geometry you created along with the options and settings you selected from each dialog box. The GUI generates commands in an object-oriented programming language called Python. The commands issued by the GUI are sent to the Abaqus/CAE kernel. The kernel interprets the commands and uses the options and settings to create an internal representation of our model. The kernel is the brains behind Abaqus/CAE. The GUI is the interface between the user and the kernel.

In a word, Abaqus use Python language to interact with the Abaqus kernel, everything that can be done in Abaqus/CAE, can also be done using Python script. Abaqus has already installed a Python interpreter so that Abaqus/CAE can use it to interact with the Abaqus kernel.

For some reasons, we cannot directly use the Python interpreter inside Abaqus to build an Abaqus model. But fortunately, we can use the commands provided by Abaqus to access it. i.e.

abaqus cae
    [database=database-file]
    [replay=replay-file]
    [recover=journal-file]
    [startup=startup-file]
    [script=script-file]
    [noGUI=noGUI-file]
    [noenvstartup]
    [noSavedOptions]
    [noSavedGuiPrefs]
    [noStartupDialog]
    [custom=script-file]
    [guiTester=GUI-script]
    [guiRecord]
    [guiNoRecord]

Usually, we can use the noGUI-file or script-file to execute our Python script in Abaqus.

Another Python interpreter, is the Python interpreter installed by ourselves, where abqpy is installed. abqpy provides a bridge to connect our Python script to Abaqus Python interpreter, it provides type hints for Python scripting for Abaqus, enabling us to write a Abaqus Python script quickly.

How does this package work?

abqpy is just a package to provide type hints for Abaqus/Python scripting, it is installed outside Abaqus/Python environment, you can use abqpy to write your Abaqus/Python scripts, and run the scripts inside Abaqus on your own. However, with the help of Abaqus command, an easier way can be achieved: you can actually run the script using your own Python interpreter without opening Abaqus, which is achieved via the abaqus command like this:

abaqus cae noGUI=script.py

The secret is hided in the run() function:

def run(cae = True):
    abaqus = os.environ.get("ABAQUS_BAT_PATH", "abaqus")

    filePath = os.path.abspath(__main__.__file__)
    args = " ".join(sys.argv[1:])

    if cae:
        os.system(f"{abaqus} cae noGUI={filePath} -- {args}")
    else:
        os.system(f"{abaqus} python {filePath} {args}")
    sys.exit(0)

In this package, the abaqus module is reimplemented to automatically call this function. If you import this module in the top of your script (i.e., from abaqus import *), your Python interpreter (not Abaqus Python interpreter) will call this function and use the abaqus command to submit the script to Abaqus. After it is submitted to Abaqus, run() will exit the interpreter, because the script will already run in Abaqus Python interpreter.

In the output script, we might not want to always use the abaqus module, because it needs the Abaqus/CAE kernel (and its license). Instead, we use the module odbAccess (i.e., from odbAccess import *), which requires only the Abaqus Python interpreter. Then, another similar abaqus command line is needed:

abaqus python script.py

So, the odbAccess module is also reimplemented to call the run() function with the argument cae = False.

In summary, the run() function will be called when you import one of the two modules (abaqus or odbAccess). It will pass the argument cae = True in abaqus module and cae = False in odbAccess module. Therefore, if you want to run your Python script in Abaqus Python environment, please make sure to import one of these modules on the top of your script.

Write your Abaqus/Python script

After installing the abqpy package, you can start writing your own Abaqus/Python script to build your model. You can refer abqpy/examples at main · haiiliin/abqpy for some script examples. Or you may go Tutorials for a simple tutorial. For more documentation about Abaqus/Python scripting, please check Abaqus Class References for more detailed API references.

Setup your Abaqus Environment

Make sure the abaqus command is available in the command line (i.e., you can run abaqus in the command line), otherwise, add a new system variable named ABAQUS_BAT_PATH, and set the value to the file path of the Abaqus command, for example, C:/SIMULIA/Commands/abaqus.bat.

Run your Abaqus/Python script

Now you can run your Abaqus/Python script with the following methods:

  • Open Abaqus/CAE and click Run Script in the menu bar, then select your script file, which is the most common way to run a Python script in Abaqus/CAE.

  • Use the abaqus command in the command line:

    abaqus cae script=script.py
    

    See here for more information about the abaqus command.

  • Use the abqpy command in the command line:

    [python -m] abqpy cae script.py
    

    The advantage using abqpy command instead of using abaqus command directly is that you are able to customize the default python launch command. See Command Line Interface for more information about the abqpy command.

  • Use the Python 3 interpreter to run the script directly:

    python script.py
    

    This is the most convenient way to run the script, it is equivalent to the abqpy command with some default predefined arguments.

  • Use the abqpy.cli.abaqus object (an abqpy.cli.AbqpyCLI object) to run the script:

    from abqpy.cli import abaqus
    abaqus.cae(script="script.py")
    

    The abqpy.cli.abaqus object is the object used for the abqpy command, you can call the methods in this object directly to run the script. This method is convenient when you want to call the Abaqus/Python script in another Python script since typing annotations are provided for the methods, so you can check the docstring of the methods for more information.

Warning

abqpy does not support debugging since Abaqus does not provide a debugger for Python scripting outside Abaqus/CAE. If you run the script under the debug mode, the script will not be submitted to Abaqus, but it will run in the Python interpreter where abqpy is installed. Since abqpy does not implement the whole Abaqus/Python APIs, the script may not (and most likely) run correctly. However, for some simple scripts, it may work, in this way you can use the debugger to check the variables in the Abaqus API roughly. But still, the script will not be submitted to Abaqus.

  • Create an Abaqus Model

    Create an Abaqus Model
  • Extract Output Data

    Extract Output Data

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