CalculiX consists out of two programs;
cgx: pre- and postprocessorccx: solverA minor annoyance is that the naming of element types is not consistent between them.
Below is a table that provided a mapping between the two.
In this article an FEA workflow based on CAD geometry in the form of STEP files and gmsh for mesh generation and CalculiX as the solver will be discussed. This workflow is primarily suited for isotropic materials.
If one is working with FreeCAD, the FEM workbench enables a similar workflow, if gmsh and CalculiX are installed. But the author prefers this method because it makes the details of the process more transparent and accessible.
All the software used here is freely available. On UNIX-like systems (e.g. FreeBSD, Linux) it can generally be installed by the native package manager. Installing the prerequisites under ms-windows is outside the scope of this article.
The Dutch-language engineering book “Constructieprincipes” by M.P. Koster contains flexure made out of four folded leaf springs that kind of acts like a ball joint.
The point where the load is applied should rotate around a virtual center formed by the point where the fold lines meet. The goal of this article is to simulate that and see if it works.
Rectangular tubes are one of the standard shapes of beams. This article shows how to create them in CalculiX GraphiX.
In this article a methd of creating a second order hex mesh for circular cross-sections will be shown.
Composite sandwich products loaded in bending tend to fail by buckling of the laminate under compression. The author’s intuition is that corrugating the surface under compression should help. So the question is; does it help, and how much. That is what will be investigated in this article.
The line command in CalculiX Graphics can create lines, arc and splines
but not elliptical arcs.
This article describes how to approximate elliptical arcs using splines.
In this article the difference in the images of the stresses between a quadrilateral hexahedron (“hex”) mesh and a tetraeder (“tet”) mesh will be investigated. In both cases, second order elements will be used.
Hopefully this will make it clear to the reader why hex meshes are generally preferred.
The plate with a hole that was the subject of a previous article will again be used. The analyses will be done using CalculiX.
The way FEA works can lead to concentrations of high stress in single elements or even nodes. This article aims to show how such singularities can be recognized and when they can be safely ignored.
Since some time, I’ve had the problem that generating hardcopy images from
cgx doesn’t work properly; the pictures are inverted vertically.
At first, I thought this might have been a change in cgx. But comparing
the source code for cgx.c for 2.16 up to and including 2.19, I don’t see
anything that would explain it.