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calculate applied force on corrugated plate.

Asked by Jinsu Jang

Hi
I'm trying to make a sheared granular fault gouge model.

I've almost developed the model setup.

Before I worked, I set up the plain plate (upper plate of boxes) to apply the normal stress to gouge particles so that It's more simple
to calculate the applied force to the plain plate.

Now, I changed the upper plate to a corrugated plate, so I think I need a new approach for calculating normal and shear stresses.
The corrugated plate is composed of several facets.

I guess that the stress is calculated by measuring particles that are in contact with the corrugated plate.
I expect that the function O.foreces.f(id) would calculate contacted stresses.

If my guess is right, the stress should be calculated by following way:
1) sum(the forces applied on facets)/sum(the area of facets)
2) sum(the stress of each facets)
*The forces applied on facets are measured using O.forces.f(facets' id)

In summary, I want to ask three questions.
1) Dose O.forces.f(id) calculate the forces of the contacted particles/facets?
2) If 1) is right, for the plate composed of several facets, the force of the plate is the sum of the forces of each faect?
3) the normal and shear stress on the corrugated plates is obtained from these forces?

Thank you, I hope my question and your answer would contribute YADE and help users!

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Jinsu Jang
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Jan Stránský (honzik) said : 		#1

Hello,

> I expect that the function O.foreces.f(id) would calculate contacted stresses.

It calculates force (not stress).
But you are using it correctly afterwards..

> 2) sum(the stress of each facets)

This (plain sum of stresses of facets) probably makes no sense..

> 1) Dose O.forces.f(id) calculate the forces of the contacted particles/facets?

depending on what "contacted particles" means.
O.forces.f(id) returns total force on the body.
In the case of a facet "loaded" from only one side, it would be the contact force

2) If 1) is right, for the plate composed of several facets, the force of the plate is the sum of the forces of each faect?

yes

3) the normal and shear stress on the corrugated plates is obtained from these forces?

Yes, it can be done.

Cheers
Jan

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Jinsu Jang (pucallpa) said : 		#2

Thank you for you answering. It's very helpful to me.

but, I'd like to ask one more question.

How the stiffness between courrugated plate (/\/\/\/\) and particles is measured?

In the case of flatten(-----------) case, I measure stiffness between plate and contacted particles.

but the case of corrugated plate, I defined stiffness between corrugated plate and contacted particles, but I think it's too large than previous case.

In my guess, stiffness of courrgated plate is average of sum of stiffness becuase, the stress is calculated from Force and contact area so that sum of forces from all facets is needed, but stiffness is not.

Thank you again!

Revision history for this message
Jan Stránský (honzik) said : 		#3

> How the stiffness between courrugated plate (/\/\/\/\) and particles is measured?

It depends how you define it.
You can then measure it according to your definition.

> but I think it's too large than previous case.

It is possible.
Depends on definition and actual simulation (e.g. ratio of particle size / plate "roughness" etc.)

> In my guess, stiffness of courrgated plate is average of sum of stiffness

Either average or sum.
"Average of sum" does not make much sense IMO..

Stiffness is similar case to the stress.
Plain sum of the stiffnesses (similar to plain sum of the stresses) has no physical meaning.
(again, IMO, quickly writing the answer. I might be wrong, you have to think carefully and critically about the answers :-).

> becuase, the stress is calculated from Force and contact area so that sum of forces from all facets is needed, but stiffness is not.

yes, see above

Cheers
Jan

Revision history for this message
Jinsu Jang (pucallpa) said : 		#4

I appreciate your help.

It's getting more clear!!