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Re: [Question #696060]: How to make some stress plates consist of 3 circles (that have radius gradually (0.5, 1, 2)?

 

Question #696060 on Yade changed:
https://answers.launchpad.net/yade/+question/696060

Jan Stránský posted a new comment:
The key point here is that you should know what and how you want to
compute.

Randomly modifying the code (sorry, but the last code seems like that)
is rarely the way to go.

So, let's take the "last option".
You know all the interactions (i.e. essentially all the forces and their positions) acting on the bottom plate.
How to convert this discrete informations to continuum-like stress?
In general, this is not unique transformation and you can have many possible ways.
One crude option is to define a region, select forces acting in the region, sum them and divide by the area of the region.
But it will be very sensitive to the cases "at the boundary" -  a force just inside or just outside, a very small difference in action point could result in a jump change in the resulting stress.

So a better option might (or might not :-) be to do some "smoothing" -
weighted average with weights being distances from the region boundary.

We can help you how to code it, maybe also give some suggestions, but
you have do the decision what/how to compute.

> interactions = [i for i in interactions if (i.geom.area1).norm()]

i.geom is ScGeom [1]. It does not have 'area' nor 'area1'
What should the condition "if (i.geom.area1).norm()" do?

> cp = [i.geom.area1 for i in interactions]
> fs = [i.phys.normalForce + i.phys.shearForce for i in interactions]
> StP = (fs,cp)/area1

cp and fs are lists of vectors. cp is list of contact points, fs is list of forces.
What should "(fs,cp)" do?
Now, "(fs,cp)" would be tuple of lists of vectors, something like ([Vector3(...), Vector3(...), ...], [Vector3(...), Vector3(...), ...])
Dividing this by area1 would result in error

> circle stress plate

Do you want an average stress inside the entire circle?
Or average stress at the boundary of the circle?
Or ... ?

> I am willing to add more circle stress plate

once you have one circle, more circles is easy task

cheers
Jan

[1] https://yade-dem.org/doc/yade.wrapper.html#yade.wrapper.ScGeom

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