yade-users team mailing list archive

[Klaus Thoeni <Klaus.Thoeni@xxxxxxxxxxxxxxxx>]

On Sat, 4 Jun 2011 06:50:57 pm honzik wrote:
> Question #159902 on Yade changed:
> https://answers.launchpad.net/yade/+question/159902
> 
>     Status: Open => Answered
> 
> honzik proposed the following answer:
> >3) How can I simulate a flexural test? like that
> >http://www.substech.com/dokuwiki/lib/exe/fetch.php?w=&h=&cache=cache&media
> >=3-point_flexure.png Once again, what is the best way to do it? Is there a
> >function similar to the unixialstrainer to do it? 'Cause a solution is to
> >do it with forceEngine applied directly on spheres, but it's not
> >convenient at all. Another solution would be to create a rectangular
> >geometry and to apply a stress on it.
> 
> You can simulate it in the same way as experiments, i.e. prescribe vertical
> displacement in the point where the force is applied and evaluate the
> reaction. It is a standard way to obtain stress-strain (or
> displacement-force) diagram in displacement-controlled tests. The supports
> can be simulated in many ways, I would do something like (for simply
> supported beam) fixing vertical and horizontal displacement of particles
> in left lower corner and fixing vertical displacement of particles in
> right lower corner. Another way is, as you wrote, to define rigid cubes
> and model supports by them.
> 
> >5) Which IPhysDispatcher Ip2 I'll need? Does it seem realistic for you
> >Ip2_CpmMat_CpmMat_CpmPhys for the concrete and
> >Ip2_WireMat_WireMat_WirePhys for the steel?
> 
> I don't know if some dispatcher to handle CpmMat and WireMat interaction
> would be needed..

Indeed, you would need a new dispatcher in order to use CpmMat together with 
WireMat. 

> >7) Finally, what about the geometry and degrees of freedom? Most of time
> >there are only 3 degrees of freedom, am I right? why not 6?
> 
> The Dem3DofGeom means that the bond between two particles has 3 degrees of
> freedom components (normal and two shear components), i.e. there is no
> bending or twisting. In Yade there are definitely some models using 6dofs.

Just remember, my current implementation of the WireMat considers just one DoF 
(normal displacement->tensile normal force) for the steel. So it should work 
fine for the pull-out test. I'm not sure about the bending test.

> What kind of steel behavior do yo want to simulate? only simple yielding
> in normal direction and pullout of steel bar from concrete? for this
> purpose even special definition of CpmMat could be sufficient :-D

It might be a good point to start with. It's always easier to deal with one 
material and just adapting the material properties.

Klaus

-- 
Dr. Klaus Thoeni - Centre for Geotechnical and Materials Modelling
Civil, Surveying and Environmental Engineering - Engineering Building EA
The University of Newcastle, Callaghan, NSW 2308, Australia
web: http://www.newcastle.edu.au/research-centre/cgmm
phone: +61 (0)2 4921 5118