yade-dev team mailing list archive

[chiara modenese <c.modenese@xxxxxxxxx>]

On 7 June 2010 07:13, Luc Sibille <luc.sibille@xxxxxxxxxxxxxx> wrote:

> Hi,
>
> It is just to give some details about strain localization. I don't think
> you need a menbrane to obtain shear band, it has already been found in a
> rigid cubical box with the DEM, and experimentally on sand with the
> apparatus TRITRI in lab. 3S-R. Experimentally they found that the shear band
> was reflected on the rigid boundaries.
>

> About periodic boundaries, I think I have already seen shear band with
> periodic boundaries, but shear band are somehow constraint since they have
> to verify the periodicity.
>
If it is true that shear bands might be a natural phenomenon, then also with
a PBC it is possible to see them. But I think you are right, Luc, that the
constraint due to the periodicity could be a "problem". At least it would be
almost impossible a study of the inclination of the bands, which would be
inevitably affected by the periodicity.

Janek, may I ask you how is your membrane going? I am just very curious, it
would be much more than interesting to have it in Yade.
thanks, Chiara

>
> Best,
>
> Luc
>
> Janek Kozicki a écrit :
>
>  Hi,
>>
>> I'm thinking about implementing membrane in triaxial test, in order
>> to be able to see localization due to internal shearing.
>>
>> questions:
>> 1) was it done already by someone, and I missed this?
>>
>> 2) it is maybe not necessary, because periodic boundaries also allow
>> to see localization due to shearing? (I doubt that, because the shift
>> on one side is on different height than the shift on right side).
>>
>> I would do this in following way: detect which spheres are on the
>> outer boundary (so they are touching the membrane), and push them
>> inside with some force.
>>
>> To detect spheres that touch the membrane I will do a Delaunay
>> triangulation of whole sample, with extra four points added. Each of
>> those four points is on the exterior of the sample and is a
>> "membrane point". Any sphere that gets connected through Delaunay
>> with this point must be lying on the boundary and is in contact with
>> membrane.
>>
>> do you have any comments on that?
>>
>> I suppose that eigen has Delaunay triangulation. Previously I was
>> using wm3 for that.
>>
>>
> --
> Luc Sibille
>
> Université de Nantes - Laboratoire GeM UMR CNRS
>
> IUT de Saint Nazaire
> 58, rue Michel-Ange - BP 420
> 44606 Saint-Nazaire Cedex, France
>
> Tel: +33 (0)2 40 17 81 78
>
>
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