yade-users team mailing list archive

[Bruno Chareyre <bruno.chareyre@xxxxxxxxxxx>]

> Hmmm, can you have transient contacts with cohesion (traction)?
Yes. You must use the DistantPersistentSAPCollider. The only difference 
with PersistentSAPCollider is :

-in PersistentSAPCollider, if overlap<0, then interaction->isReal=false 
and interaction is removed

-in DistantPersistentSAPCollider, if (overlap<0 && 
interaction->isReal==false) then the interaction is removed

This modified collider must be used with 
InteractingSphere2InteractingSphere4DistantSpheresContactGeometry (I 
know you love long names!).

In 
InteractingSphere2InteractingSphere4DistantSpheresContactGeometry.hpp, 
you can see this comment :

"////This engine is designed to work with the 
DistantPersistentSAPCollider, the go method does not return
///false when an interaction exists - even if there is no overlap."/

So, the value of interaction->isReal is no longer defined based on 
geometrical properties. Instead of that, it has to be defined in the 
contact law, so that isReal==false ONLY IF the interaction is broken AND 
there is no overlap (see CohesiveFrictionalContactLaw).

Example usage in CohesiveTriaxialTest preprocessor.


>  How
> would I do uniaxial traction test without persistent links? Or uniaxial
> compression without confinement?
>
>   
I think all you need is an interaction law that will set isReal=false 
when contact is broken in traction. I am not sure that my 
CohesiveFrictionalContactLaw is good for you, so perhaps you have to 
write your own contact law (very similar to existing ones in fact, same 
equations but has to set isReal=false after failure).

IMHO, persistent links could be completely removed from Yade.

Bruno




> Vaclav
>
> _______________________________________________
> Yade-users mailing list
> Yade-users@xxxxxxxxxxxxxxxx
> https://lists.berlios.de/mailman/listinfo/yade-users
>
>   


-- 
 
_______________
Chareyre Bruno
Maitre de conference

Institut National Polytechnique de Grenoble
Laboratoire 3S (Soils Solids Structures) - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 43
________________

_______________________________________________
Yade-users mailing list
Yade-users@xxxxxxxxxxxxxxxx
https://lists.berlios.de/mailman/listinfo/yade-users