Articles tagged with "CalculiX"

1. Singularities versus stress concentrations in FEA

   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.

2. Patching CalculiX Graphics to fix flipped screen hardcopy

   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.

3. Automating CalculiX with make(1)

   The make program is a staple UNIX development tool. In this article I will show how it can be used to automate and simplify the usage of CalculiX.

   My CalculiX projects are all kept in their own directories. In each of those directories there exists a Makefile. This contains instructions for the make program.

   By default, invoking make in this directory runs the pre-processor and the solver. But there are also specific sub-commands, for example:

   • “make mesh” shows the mesh used in the FEA.
   • “make disp” shows the deformed product in the post-processor.
   • “make stress” shows the stresses in the product in the post-processor.

4. Mooney-Rivlin rubber data for CalculiX

   Recently I was looking for material data for 60 Shore A rubber for a simulation. This article describes what I found and how I transformed that to material data.

5. FEA with Calculix (3)

   This is the third installment of a series of articles about how to analyze sandwich structures with FEA.

   It might be a good idea to read part 1 and part 2 first.

   In this part we will look at a simplified simulation of a three-point bending test of a sandwich panel.

6. FEA with Calculix (2)

   This is the second part in a series how to analyse sandwich structures with FEA. The first part is here. If you haven’t done so, you should probably read that first.

   In that part we built and analyzed a sandwich where the core and skins shared nodes. We saw how that leads to incorrect stress distribution images because of nodal averaging. In this article, we’re going to fix that by using *TIE constraints.

7. FEA with Calculix (1)

   This is the first part of a series of articles where I hope to show how to analyze deflection and stress in structures using the free CalculiX software. I’m using version 2.17. The focus will be on sandwich structures because that is the area in which I’m most interested. Compared to parts consisting out of a single material this is a bit more tricky as we will see in this article. The main reason for using finite element analysis (“FEA”) in general is that it allows for complete analysis of problems where no integral solution exists.

   Additionally, some of the assumptions used in Euler–Bernoulli beam theory for analyzing deformation and stresses in beams and plates do not hold for sandwiches.