Yade

Force unit for wall bodies

Asked by Lukas Wasner

Hello,
I am currently reviewing several approaches to apply a Defined Load or Stress to my particle body. I want to compare the approach via TriaxialStressController (input value is the stress sigma=F/A) and via a displacement controlled settlement until a target stress is reached.

In the example script [1] for an oedometer test, the force Fz on a wall body is used. This is determined via O.forces.f(plate.id)[2]. ([2] is the third axis and not reference no. 2).

Unfortunately, it is not clear to me how to interpret the force Fz, since the wall body represents an infinite plane.

A first thought was that the force Fz is a resultant concentrated load acting on the plate. If this is the case, would I just need to divide Fz by the load area to get the area-based stress (same input unit sigma as TriaxialStressController)?

Alternatively, could the force Fz be an area load? How do I then proceed to calculate a stress from this?

[1]: https://gitlab.com/yade-dev/trunk/blob/master/doc/sphinx/tutorial/03-oedometric-test.py

Many thanks,
Lukas

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Jan Stránský
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Best Jan Stránský (honzik) said : 		#1

Hello,

> A first thought was that the force Fz is a resultant concentrated load acting on the plate. If this is the case, would I just need to divide Fz by the load area to get the area-based stress (same input unit sigma as TriaxialStressController)?

Yes,
Fz is force, no involvement of area.
To get (area-based) stress, divide force with corresponding area.

Cheers
Jan

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Lukas Wasner (luek) said : 		#2

Thanks Jan Stránský, that solved my question.