# Element names in Calculix

CalculiX consists out of two programs;

`cgx`

: pre- and postprocessor`ccx`

: solver

A minor annoyance is that the naming of element types is not consistent between them.

Below is a table that provides a mapping between the two.

Please note that for mechanical analysis, second order elements are preferred above first order elements. Second order elements give more accurate results with fewer nodes and elements.

A regular mesh of **C3D20R** element generally gives the nicest results.
If that is not possible, use **C3D10** elements. Those can be generated
from arbitrary geometry (e.g. from STEP files made with CAD software like
FreeCAD) by gmsh.

Note that `cgx`

cannot mesh all element types, and others need to be done in
two steps. See the manual for details.

cgx | ccx | remarks |
---|---|---|

be2 | B31 | First order 2-node beam element. Don’t use for bending. |

te4 | C3D4 | First order 4-node tet element. Too stiff. Use C3D10 instead |

pe6 | C3D6 | First order 6-node wedge element. Use C3D15 instead. |

he8 | C3D8 | First order 8-node brick element |

he8i | C3D8I | Improved C3D8; reduced volume locking, no shear locking. |

he8r | C3D8R | First order 8-node brick element with reduced integration |

te10 | C3D10 | Second order 10-node tet element. Preferred if you can’t use C3D20R. |

pe15 | C3D15 | Second order 15-node wedge element. |

he20 | C3D20 | Second order 20-node brick element. |

he20r | C3D20R | Second order 20-node brick element with reduced integration.
Preferred |

tr3c | CAX3 | First order triangular axisymmetric element. |

qu4c | CAX4 | First order four-sided axisymmetric element. |

qu4cr | CAX4R | First order four-sided axisymmetric element, reduced integration. |

tr6c | CAX6 | Second order triangular axisymmetric element. |

qu8 | CAX8 | Second order four-sided axisymmetric element. |

qu8r | CAX8R | Second order four-sided axisymmetric element, reduced integration. |

tr3e | CPE3 | First order triangular plain strain element. Preferably use CPE6. |

qu4e | CPE4 | First order four-sided plain strain element. Preferably use CPE8. |

qu4er | CPE4R | |

tr6e | CPE6 | Second order triangular plain strain element. |

qu8e | CPE8 | Second order rectangular plain strain element. |

qu8er | CPE8R | Second order rectangular plain strain element, reduced integration. |

tr3s | CPS3 | First order triangular plain stress element. Preferably use CPS6. |

qu4s | CPS4 | First order four-sided plain stress element. Preferably use CPS8. |

qu4sr | CPS4R | First order four-sided plain stress element, reduced integration. |

tr6s | CPS6 | Second order triangular plain stress element. |

qu8s | CPS8 | Second order rectangular plain stress element. |

qu8sr | CPS8R | Second order rectangular plain stress element, reduced integration. |

tr3 | S3 | First order 3-node shell element. Preferably use S6. |

qu4 | S4 | First order 4-node shell element. Preferable use S8. |

qu4r | S4R | First order 4-node shell with reduced integration. Preferable use S8R. |

tr6 | S6 | Second order 6-node shell element. Expands to C3D15 |

qu8 | S8 | Second order 8-node shell element. Expands to C3D20. |

qu8r | S8R | Second order 8-node shell with reduced integration. Expands to C3D20R. |

For comments, please send me an e-mail.

## Related articles

- FEA based on STEP geometry using gmsh and CalculiX
- Corrugation against buckling
- Approximating elliptical arcs in CalculiX Graphics
- Hex versus tet meshes in FEA
- Singularities versus stress concentrations in FEA