← Back to team overview

yade-users team mailing list archive

Re: Gravity Engine in Triaxial test


> As you suggested, I update the latest subversion of Yade, However, when I looking in the triaxial test.cpp, the gravityengine was disabled. Do you have any class replace for this class or it is only a trial and error stuff?
I'm ignoring gravitational forces in triaxial simulations. That is why I 
removed the gravitation engine.
It is not replaced by something else.

> And can you give me some suggestion of how to take out some of the engines during the simulation (like when some values reach a threshold?)
The idea is not to remove an engine, but to change its behaviour (even 
make it do nothing is some circumstances).

An exemple :
in TriaxialCompressionEngine.cpp, you see

line 72 :

void TriaxialCompressionEngine::updateParameters(Body * body)


             if (UnbalancedForce<=StabilityCriterion && 
abs((meanStress-sigma_iso)/sigma_iso) < 0.02)
            if (autoCompressionActivation)
                compressionActivated = true;
                autoCompressionActivation = false;

meaning that if the sample is stable and the confining stress close to 
the prescribed value, the engine switch from isotropic compression to 
triaxial test (constant strain rate in one direction + constant stress 
in other directions). In fact it will switch only if the user wants an 
"autoCompressionActivation" (second test).

Then, in TriaxialCompressionEngine::applyCondition you have (line 187) :

if (compressionActivated)
        p->se3.position += 0.5*strainRate*height*translationAxis*dt;

which is moving the two walls corresponding to the loading direction, 
when compression is activated.

I hope it helps.

Perhaps if you explain what you want to do precisely (did I miss it?) we 
can have more precise ideas on how to do it.

> Thank you so much and have a nice day,

Have a nice day too :).


Chareyre Bruno
Maitre de conference

Institut National Polytechnique de Grenoble
Laboratoire 3S (Soils Solids Structures) - bureau E145
BP 53 - 38041, Grenoble cedex 9 - France
Tél : 33 4 56 52 86 21
Fax : 33 4 76 82 70 00

Yade-users mailing list