yade-users team mailing list archive
-
yade-users team
-
Mailing list archive
-
Message #24163
Re: [Question #693568]: Stresses drop to zero in periodic triaxial shear simulation
Question #693568 on Yade changed:
https://answers.launchpad.net/yade/+question/693568
Status: Open => Answered
Jan Stránský proposed the following answer:
Hello,
In your code
###
def prepareShear(rate,confinement):
...
triax.stressMask = 7
triax.goal[1] = -1e3*confinement
triax.goal[0] = triax.goal[2] = -triax.goal[1]/2
O.cell.velGrad=Matrix3(rate/2,0,0,0,-rate,0,0,0,rate/2)
...
###
> triax.stressMask = 7
> triax.goal[1] = -1e3*confinement
you set stress-controll, so strain/volume is NOT kept constant (print
also strain/volume, not only stress) but is the result of simulation
(trying to reach defined stress).
> triax.goal[0] = triax.goal[2] = -triax.goal[1]/2
you require **tensile stress** in two directions. As the triax engine
tries to reach this, it enlarges the cell, probably causing volume
enlargement and "particle separation". I suspect this also causes the
final zero stress.
> O.cell.velGrad=Matrix3(rate/2,0,0,0,-rate,0,0,0,rate/2)
this is overwritten by PeriTriaxController.
Proposed solution:
- set triax.dead = True (not to overwrite cell deformation)
- set O.cell.velGrad as it is now (without triax, the volume should be kept constant)
cheers
Jan
--
You received this question notification because your team yade-users is
an answer contact for Yade.