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[Robert Caulk <question675377@xxxxxxxxxxxxxxxxxxxxx>]

Question #675377 on Yade changed:
https://answers.launchpad.net/yade/+question/675377

    Status: Open => Answered

Robert Caulk proposed the following answer:
Hello,

>> 1) why the same rates produce different strain increments?

I do not understand your question. I ran your script, which explicitly
executes:

triax.maxStrainRate = [rate,rate,0.0]

and finally prints:

"dexx= -3.96592748642e-08  deyy= -3.96592878538e-08  dexy=
2.75274092903e-08"

Appearing to show that equivalent strain rate yields equivalent strain.
Or is it that you believe the transformation matrix, O.cell.trsf[0,1],
should be equivalent to the strain values,
triax.strain[0]=traix.strain[1]?


>> 2) why resetting the cell transformation changes the increments of strain afterwards?

It doesn't:

dexx= -3.96592803723e-08  deyy= -3.96592804735e-08  dexy=
4.00598778322e-08

The strain increments remain the same. O.cell.trsf is simply providing
you with the accumulated transformation of the cell. Or more described
in more detail by Václav [1]:

"Current transformation matrix of the cell, which defines how far is the
current cell geometry (:yref:`hSize<Cell.hSize>`) from the reference
configuration. Changing trsf will not change :yref:`hSize<Cell.hSize>`,
it serves only as accumulator for transformations applied via
:yref:`velGrad<Cell.velGrad>`."

[1]https://github.com/yade/trunk/blob/master/core/Cell.hpp#L153

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