# yade-users team mailing list archive

## Re: [Question #695058]: Bending beams mass computation

```Question #695058 on Yade changed:

Paul Pircher posted a new comment:
> You are welcome, nice to hear that someone is using it.

I can guarantee you that it will not be the last time I post questions
on this topic on the yade launchpad. For simple deformable bodies, my
team and I will most likely use it a lot in the future as soon as I know
exactly how to use it and managed to properly simulate correct beahviour
of a simple body. 😊

> Set the mass of its nodes. That's all.

Alright, thanks. Just applying the correct node density to achieve the
same total mass that I want it to have. Total node mass = wanted total
mass. Got it!

> I would say they are two alias for the same thing. Am I confused? have
seen one or the other in different scripts?

As far as I know they are multiple similar approaches in the “More examples” section of the yade documentation. Just to summarize:
-	Chained-cylinders
-	Cylinders (or cylinder-connections. The example I initially used to open this question thread.)
-	Grids
-	PFacet (although this uses creators and gridNodes and gridConnections and only adds the PFacet)
Since I am a newbie, I am not yet able to tell what the exact differences are, but they are more or less used for the same things (I believe).

> if cohesion is small you can get get plastic deformation of the beam

Ah I see. So, it is kind of needed to apply resistance to pulling. As particles only “generate” a force when moving towards, but not when moving away from each other.
Linear elastic behaviour is totally fine for my use for now. Let’s see where the journey goes.

> Bending is defined for interactions, based on the differential
rotation of two nodes. It is not defined "per node".

Since I had a look in the paper you linked: Is it correct to imagine the
bending behaviour as a rotational spring like in figure 3 of [3]? This
what I initially meant when I proposed the question on how the bending
behaviour “in a node” is computed. As a node itself can’t bend it is
somewhat clear that it needs to happen in the interactions as this links
multiple nodes.

> Effeindzourou PhD dissertation

Nevertheless it is a good summary, thanks for the hint!

> There is an old 2D version of the same thing described in [3]

As in the question above this gave some basic insights (probably). So
this is still of value. Thanks for the suggestion!

Best regards and thanks again,
Paul