Based on a question I ran into at work, I wanted to explore the influence of parameters like cross-section, wall thickness and laminate lay-up on the resonance frequency of a carbon fiber composite tube.
The goal of this exercise is to determine which of the parameters are dominant.
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.
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:
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.
During my engineering education and the start of my career, a lot of design and drafting work was still done on paper. During that time I also discovered computers, and how they could be an extra tool in my toolbox.
Although my training and career has been in mechanical engineering, there is not much about that on these pages. In this new category, I hope to remedy that.