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[liukeqi <question404228@xxxxxxxxxxxxxxxxxxxxx>]

Question #404228 on Yade changed:
https://answers.launchpad.net/yade/+question/404228

    Status: Answered => Open

liukeqi is still having a problem:
Hello Jan

Thanks for your reply. But I still have question.

[1]First, the formula to compute the Normal Stresses 
σN = [1 - ωH(εN)]kNεN in the paper page 38 
is same as the formula 
sigmaN = (1-(epsN-epsNPl>0?omega:0))*E*(epsN-epsNPl) 
in the source code ConcretePM.cpp. 

But the formula to compute damage variable 
ω = g(κ) = 1 -εf/κ*exp(-(κ - ε0)/εf) in the paper page 38 
is not same as the formula 
omega = isCohesive? phys->funcG(kappaD,epsCrackOnset,epsFracture,neverDamage,damLaw) : 1., 
funcG return 1.-(epsCrackOnset/kappaD)*exp(-(kappaD-epsCrackOnset)/epsFracture)
in the source code ConcretePM.cpp.
The formula in the source code changed to ω = g(κ) = 1 -ε0/κ*exp(-(κ - ε0)/εf). That is εf change to ε0 in εf/κ.
Which is true, paper or source code?

[2]According the source code comments, the εf(epsFracture) should be the
"strain at which the bond is fully broken". That is, when the tensile
strain reach the εf, the stress should be zero, or at least tends to
zero. But if I use the formula in paper page or 38 σN = [1 - ωH(εN)]kNεN
or the formula in source code sigmaN = (1-(epsN-epsNPl>0?omega:0))*E
*(epsN-epsNPl), if I used the same value as papar said that εf is 30ε0
and ε0 is 0.0001, the σN is about 2800000 when the εN is 30ε0, not zero!
Why?Do I have some misunderstandings about it?

Thank you.
Liu

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