This is my home in the virtual world, where I write
about things that I want to share. The freely available software that
I've written as well as some of the photographs I've taken over the
years can also be found here. Please use the navigation links on the
right if you are looking for something.
At work, we recently bought an EBI 40 TC-01 6-channel temperature logger.
It saves data in a file with the ed3 extension.
It comes with a ms-windows program to show the data and export to CSV and ms-excel.
However, I want to be able to use the data on my FreeBSD workstation.
So I have to figure out the data format of the ed3 files.
To build an epub with sphinx, we need two directories, a source and an
output.
The source directory should contain at least two files; conf.py
containing the settings for the epub conversion, and index.rst containing
the main text.
Honeycomb cores are often used in composite structures as an alternative core
material to e.g. polymeric foams or end-grain balsa.
In FEA we want to be able to treat honeycomb as a continuous material instead
of having to model individual cells.
Otherwise even simple FEA models involving honeycomb would become unmanageably large.
But if you don’t like those, you can make them yourself from music that you
are allowed to use.
All software that is used here is open source. They should work on all recent
UNIX-like operating systems. In my case, I installed all of these programs
using the FreeBSD ports system.
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.
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.
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.
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.