yade-dev team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> I tried to understand how to calculate torsional moments for clumps.
> Please have a look at the pictures in the attachment (see link above).
> There two clumps are shown and I do not understand how their torsional
> moments can be calculated. In the first picture there is box clumped
> with a "half sphere". In the second picture you can see a box inside a
> sphere, like I want to model my sand grains in future. How is
> torsional moment calculated in this cases?
I don't understand the question, sorry. Torsional/bending moments are
defined for interactions, not for individual bodies (even if the bodies
are clumps, it makes no difference). Your pictures have only one body,
how could you define torsional moments?
> Can this be simulated with RotationEngine already?
RotationEngine is not related to your problem, it is only prescribing
motion.
>> For box-box interactions, there is a serious background in 3-DEC from
>> itasca, where arbitray polyhedral shapes are modelized. It should apply
>> to boxes.
>
> Hm, I think in the case of cubids (boxes) it should be much easier,
> than a general polyhedral shape.
Sure, but you will find interesting ideas in 3DEC regarding contact
formulation.

>
>> My only question is if it is really necessary to modelize angular
>> vertices instead of rounded shapes.
>
> If I want to model rounded shapes, I could clump spheres,
Not really, a rounded box has flat surfaces that you will never have by
clumping spheres. The contact between two flat surfaces will transmit
moments.

Bruno