It’s been almost a year since I wrote my post on how to model friction in a dynamic multibody system. Since then, I’ve reconsidered my ideas from the post a few times and finally found out that there’s a theory called “hybrid systems” that intersects with the problems described there.

# Modelling friction in 1d dynamics

Let’s assume you want to model a multibody system that includes friction. This seems like a quite reasonable idea to me and in this post, I’ll share what I’ve learned when doing exactly this in GNU Octave (or Matlab – doesn’t matter much since we’ll use quite basic functionality).

# Getting started

This is an experiment that has been bugging me for quite a while.

Every now and then I run into some applied mechanics problem and try to figure out how to solve it. Usually after a few minutes of trying, I also decide to google it and often I find no solution to my question (but usually a lot of helpful hints and good advice).

These are usually quite basic questions I’m considering, like:

- how can I implement coulomb friction in a 1d mechanics model with consideration of stick and slip states?
- my multibody model is getting quite complex with lots of reused code. The code would probably look a lot cleaner and simpler if masses and couplings are implemented as objects. How can this be done?

Both example questions are actually quite simple problems which are probably solved many times. Searching for a good solution is fun for me and I usually learn a lot along the way. So this is the idea of this blog: to write about simple problems with multibody dynamics and suggest possible solutions to them – and then see what happens.