ADA - Assembly for Design & Analysis

A python library for working with structural analysis and design. Ada-py delivers an object-oriented framework for CAD/BIM/FEM modelling, interoperability and Finite Elements (FE) post-processing.

To install the latest "stable" ada-py package into an existing conda environment

conda install -c krande -c conda-forge ada-py

or if you wish to download the latest build from any branch passing unittests you can do

conda install -c krande/label/dev -c conda-forge ada-py

Alternatively create a new isolated environment for the installation like so:

conda create -n ada -c krande -c conda-forge ada-py

With ada-py you can (among other things) convert your FE models to IFC, create your own recipes for creating FE mesh from your IFC models, or build your design from the ground up using fully customizable and extendible python classes and functions to build parametric designs with rules for automated joint/penetration identification and steel detailing.

Additionally, you can create unittests to not only test the code that makes your structure, but also create tests that checks the capacity of your structure by running FE analysis on it and validating the resulting stresses and strains generated by your FE software of choice.

And since everything is open source and written in regular python you are free to easily customize and create whatever design and analysis pipeline of your choosing.

The FEM formats that has received the most development are Abaqus and Code Aster (the latter being under development now), but there is also basic support for Calculix, Sesam and Usfos. There is also support for conversion of FEM meshes to/from meshio (which supports many more FEM formats, but does not support FEM information such as beam/shell thickness, materials etc..)

Part of the goal is to build the necessary tools for anyone to add support for their favorite FEM format with as few lines of code as possible.

This library is still undergoing significant development so expect there to be occasional bugs and breaking changes.

Quick Links

Try ada-py online (main branch / dev branch) with code-aster and calculix pre-installed

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• Feel free to start/join any informal topic related to adapy here.
• Issues related to adapy can be raised here

Usage

Some examples of using the ada package

Create an IFC file

The following code

from ada import Assembly, Part, Beam

a = Assembly("MyAssembly") / (Part("MyPart") / Beam("MyBeam", (0, 0, 0), (1, 0, 0), "IPE300"))
a.to_ifc("C:/temp/myifc.ifc")

creates an Ifc file containing an IfcBeam with the following hierarchy

MyAssembly (IfSite)
    MyPart (IfcBuildingStorey)
        MyBeam (IfcBeam)

The resulting IfcBeam (and corresponding hierarchy) shown in the figure above is taken from the awesome blender plugin blenderbim.

Convert between FEM formats

Here is an example showing the code for converting a sesam FEM file to abaqus and code aster

Note! Reading FEM load and step information is not supported, but might be added in the future.

from ada import Assembly

my_fem_file = 'path_to_your_sesam_file.FEM'

a = Assembly()
a.read_fem(my_fem_file)
a.to_fem('name_of_my_analysis_file_deck_directory_abaqus', 'abaqus')
a.to_fem('name_of_my_analysis_file_deck_directory_code_aster', 'code_aster')

# Note! If you are in a Jupyter Notebook\lab environment 
# this will generate a pythreejs 3D visualization of your FEM mesh
a

Current read support is: abaqus, code aster and sesam
Current write support is: abaqus, code aster and sesam, calculix and usfos

Create and execute a FEM analysis in Calculix, Code Aster and Abaqus

This example uses a function beam_ex1 from here that returns an Assembly object with a single Beam with a few holes in it (to demonstrate a small portion of the steel detailing capabilities in ada and IFC) converted to a shell element mesh using a FE mesh recipe create_beam_mesh found here.

from ada.param_models.fem_models import beam_ex1

a = beam_ex1()

a.to_fem("MyCantilever_abaqus", "abaqus", overwrite=True, execute=True, run_ext=True)
a.to_fem("MyCantilever_calculix", "calculix", overwrite=True, execute=True)
a.to_fem("MyCantilever_code_aster", "code_aster", overwrite=True, execute=True)

after the code is executed you can look at the results using supported post-processing software or directly in python using Jupyter notebook/lab (currently only supported for Code Aster) for the FEA results.

To access the stress and displacement data directly using python here is a way you can use meshio to read the results from Calculix and Code Aster (continuing on the previous example).

from ada.config import Settings
import meshio

vtu = Settings.scratch_dir / "MyCantilever_calculix" / "MyCantilever_calculix.vtu"
mesh = meshio.read(vtu)

# Displacements in [X, Y, Z] at point @ index=-1
print('Calculix:',mesh.point_data['U'][-1])

rmed = Settings.scratch_dir / "MyCantilever_code_aster" / "MyCantilever_code_aster.rmed"
ca_mesh = meshio.read(rmed, 'med')

# Displacements in [X, Y, Z] at point @ index=-1
print('Code Aster:',ca_mesh.point_data['DISP[10] - 1'][-1][:3])

Note!

The above example assumes you have installed Abaqus, Calculix and Code Aster locally on your computer.

To set correct paths to your installations of FE software you wish to use there are a few ways of doing so.

1. Add directory path of FE executable/batch to your system path.
2. Add directory paths to system environment variables. This can be done by using the control panel or running the following from a cmd prompt with administrator rights:

:: Windows
setx ADA_abaqus_exe <absolute path to abaqus.bat>
setx ADA_calculix_exe <absolute path to ccx.exe>
setx ADA_code_aster_exe <absolute path to as_run.bat>

:: Linux?

:: Mac?

3. Set parameters in python by using environment variables or the ada.config.Settings class, like so:

import os
os.environ["ADA_calculix_exe"] = "<absolute path to ccx.exe>"
os.environ["ADA_abaqus_exe"] = "<absolute path to abaqus.bat>"
os.environ["ADA_code_aster_exe"] = "<absolute path to as_run.bat>"

or

from ada.config import Settings
Settings.fem_exe_paths["calculix"] = "<absolute path to ccx.exe>"
Settings.fem_exe_paths["abaqus"] = "<absolute path to abaqus.bat>"
Settings.fem_exe_paths["code_aster"] = "<absolute path to as_run.bat>"

Note! It is very important that any paths containing whitespaces be converted to "shortened paths". To shorten a path on windows you can use the utility pathcopycopy.

For installation files of open source FEM software such as Calculix and Code Aster, here are some links:

• https://github.com/calculix/cae/releases (calculix CAE for windows/linux)
• https://code-aster-windows.com/download/ (Code Aster for Windows Salome Meca v9.3.0)
• https://www.code-aster.org/spip.php?rubrique21 (Code Aster for Linux)
• https://salome-platform.org/downloads/current-version (Salome v9.6.0 for windows/linux)
• https://prepomax.fs.um.si/downloads/ (PreProMax -> Calculix preprocessor)

Alternative Installation methods

If you have to use pip you can do:

pip install ada-py gmsh

Note! Pip will not install the required conda packages. Therefore you would also have to do

conda install -c conda-forge ifcopenshell pythonocc-core==7.5.1 occt==7.5.1

Note! pip is not a recommended installation method due to an unstable behaviour often manifested as DLL import errors related to the vtk package.

Acknowledgements

This project would never have been possible without the existing open source python and c++ libraries. Although listed in the package dependencies (which is a long list), here are some of the packages that are at the very core of adapy;

• Ifcopenshell
• Pythonocc-core
• Gmsh

And the following packages are integral in the interoperability and visualization of FEM results.

• Vtk
• Pythreejs
• Meshio
• Ccx2paraview

A huge thanks to all involved in the development of the packages mentioned here and in the list of packages adapy depends on.

If you feel that a certain package listed in the adapy dependencies should be listed here please let me know and I will update the list :)

Project Responsible

Kristoffer H. Andersen