Creating Supports in SystemModeler ....

[ngrcurrie (Neil)]

I’m slowly grinding through the tutorials in the getting started guide and would like to try and build on the chain link pendulum example.

Firstly I tried to fix the end of the pendulum, so that the chain would drape. Screenshot of my model below.

Then my second goal is to create a horizontal roller support, so that the rotational springs could hold it in position through their rotational stiffness.

I’d genuinely appreciate any guidance on how to create a horizontal roller, or create multiple support points.

*The spirals are revolute joints, with springs and dampeners attached. If I remove the fixed translation component, the model functions quite happily as a chain pendulum.

All help gratefully received.

[johanr (Johan Rhodin)]

Hi Neil,

Not sure what you want to accomplish. Can you show a picture or a sketch of the system or mechanism that you are trying to model?

Here’s a model with two supports:

Animation:

[ngrcurrie (Neil)]

Thanks for the response.

What I’d like to create are two supports, with a prescribed distance between them.

Between these two supports will be a series of links, whose total combined length would be greater than the distance between the supports.

Using revolute joints between each link, I would like to model the links so they drape between the two supports under their selfweight.

The idea being that I could reverse the geometry, include rotational springs on the revolute joints and make a springy arch that can support loads, with its load carrying capacity being driven by the stiffness of the springs.

I hope this makes sense, I’m not near a scanner for a few days else I would draw a sketch.

[ngrcurrie (Neil)]

Diagram below of what I would like to achieve as a system, once stable I would like to place forces and/or accelerations to the red nodes.

I hope this makes sense…

[johanr (Johan Rhodin)]

I see. You can modify my above model slightly:

This will generate a simulation that looks like this:

You can add forces with the Modelica.Mechanics.MultiBody.Forces library.

[ngrcurrie (Neil)]

Brilliant, thank you very much. It was the addition of the special revolute joint at the end to prevent it being a planar loop that was eluding me.