pycalculix

pycalculix is a Python 3 library to automate and build finite element analysis (FEA) models in Calculix.

Meshing uses Calculix or GMSH

• Website: http://justinablack.com/pycalculix/
• Source Code: https://github.com/spacether/pycalculix
• Documentation: http://pythonhosted.org/pycalculix/

Usefull applications of Pycalculix:

• Trade studies for plane stress, plane strain, or axisymmetric parts
• Quick Kt analysis of 2D geometry
• Learning finite element analyis (FEA) and Python

Installation

Mac OS X

1. Install python3, pycalculix and the fea programs that it uses

brew install python3
python3 -mpip install -U numpy
python3 -mpip install -U matplotlib
pip3 install pycalculix
pycalculix-add-feaprograms

2. You are done! See 'Usage'

Windows

1. Install python3 for 32bit machines or 64 bit machines
2. In a terminal run the below lines to install needed python libraries, pycalculix, and the fea programs that it uses

python -mpip install -U numpy
python -mpip install -U matplotlib
pip install pycalculix
pycalculix-add-feaprograms

Note: the second line installs the calculix and gmsh programs on your computer Running these included binaries from pycalculix only works for windows.
3. You are done! See 'Usage'

Linux, assumes Ubuntu 16.04

1. Install python3-pip, numpy, matplotlib, pycalculix, and the fea programs that it uses

sudo apt-get install python3-pip python3-tk
pip3 install --upgrade pip
python3 -mpip install -U numpy
sudo python3 -mpip install -U matplotlib
pip3 install pycalculix
pycalculix-add-feaprograms

2. You are done! See 'Usage'

Usage

1. To run a pycalcuix file you have to have pycalulix installed, see 'Installation' above
2. The you can then write your own pycalculix programs or run one of the example files here: https://github.com/spacether/pycalculix/tree/master/examples
3. To run a file:

Windows

• Graphical user interface:
  • Double click the file
    If the .py extension is associated correctly you can double click it to run the .py program
• Console:
  • cd into the directory with your .py file in it, then in the terminal enter

  python the_program.py
  

  where the_program.py is the name of the file that you are running This assumes that python3 is your active python installation

Mac/Linux

• Console:
  • cd into the directory with your .py file in it, then in the terminal enter

  python3 the_program.py
  

  where the_program.py is the name of the file that you are running

Elements Supported:

Axisymmetric, plane stress, and plane strain elements are supported.

• First and second order triangles and quadrilaterals are supported.
  • First order elments only have corner nodes
  • Second order elements have corner and midside nodes

Second order elements produce more accurate results Setting element divisions on lines is supported

Geometry Building

• One can build separate parts made of points, lines, arcs, and areas.
• Straight lines and arcs are currently supported.
• One can draw a part made of straight lines, then smooth out corners by adding arcs with the part method: part.fillet_lines(L1, L2, arc_radius)
• The new arc will be tangent to both adjacent lines.

Loading

• Force loading
• Constant pressure
• Linearly varying pressure (water pressure)
• Gravity
• Rotational speed forces
• Displacement constraints
• Loads are stored on geometry primitives (points lines, areas) and can be applied before or after meshing.

Files Produced

Meshing and solving are done in the background using cgx or gmsh for meshing, and Calculix ccx for solving.

Files Used:

• .fbd (Calculix cgx gemetry file)
• .inp (Calculix solver input file, or mesh definition)
• .geo (Gmsh geometry file)
• .msh (Gmsh native mesh file)
• .frd (Calculix ccx nodal results file, values are at nodes and were created by interpolating element integration point results back to the nodes)
• .dat (Calculix ccx element results file, includes integration point results)

Uninstall

Windows

pycalculix-remove-feaprograms
pip uninstall pycalculix

Mac/Linux

pycalculix-remove-feaprograms
pip3 uninstall pycalculix

License

See LICENSE.txt (Apache 2.0)

Creator

Justin Black, justin.a.black[at-sign]gmail[dot]com Initial Release: December 2014

Change Log

0.9.4 (github only)

• removed gmsh and calculix
• moved dist and documentation building and example cleanup into make file
• changed the license to Apache 2.0
• added command line tool to install/uninstall gmsh and ccx for windows/mac os x/ubuntu
  • pycalculix-add-feaprograms
  • pycalculix-remove-feaprograms

0.9.3

• ADDED: multiple parts with contacts
  • See example files: pipe-crush-elastic.py, pinned-plate.py
• ADDED: Import CAD geometry from dxf file
  • See pycalculix.CadImporter
  • Examples:
    • import-dxf.py
• ADDED: Element results plotting added
  • Element results plotting: pycalculix.Problem.rfile.eplot()
  • Nodal results plotting: pycalculix.Problem.rfile.nplot()
  • Number Formatting:
    • Strain results now use scientific formatting
    • Others use nearest 10**3 suffixes
  • Max and min values now listed above the colorbar
• ADDED: method to draw an arc by swept angle in degrees
  • part.draw_arc_angle(degrees_ccw, center_x, center_y)
• ADDED: min_val and max_val can now be passed to eplot and nplot
  • This lets the user set the results range that they want to see:
  • min_val <= colored results <= max_val
  • Values under and over are greyed out, darker under, lighter over
• ADDED: internal holes in parts
  • One can make circular holes, or draw complicated holes.
  • See examples:
    • hole-in-plate-full.py, multihole.py
• ADDED: Added set_ediv method to FeaModel class.
  • This method sets the number of elements on a line.
  • line.set_ediv still works.
• ADDED: Robust selection object: feamodel.view
  • This object is feamodel.view Most important methods are:
    • view.select_all, view.select, view.allsel_under
    • All plotting now uses the current selection set
  • SYNTAX: updated how parts, materials, problems are made
    • Make part:
      • pycalculix.FeaModel.make_part or pycalculix.Part
    • Make material:
      • pycalculix.FeaModel.make_matl or pycalculix.Material
    • Make problem (previously called model):
      • pycalculix.FeaModel.make_problem or pycalculix.Problem
    • Make Results File:
      • pycalculix.Problem.rfile or pycalculix.ResultsFile(problem)
• FIX: Plotting fix, closing triangles in the correct direction in matplotlib
• DOC: All code separated into modules for clarity.
• DOC: Docstrings added to all classes + methods + functions
• PLOTTING: Closed areas are now filled in yellow when plotting geometry.
• PLOTTING: Signed line names are shown and internal to the area.
• BACKEND: Implemented signed line and signed arc class.
  • Pressures can now be applied on these signed lines.
  • Many methods and variables made private to clean up name space.

Developer Todo:

• installer.py:mac_add search for ccx path before symlinking to it
• fix the error where FRD files can no longer be read
• confirm that set_ediv still works, remove the past merge if that broke it