Hello Vaclav, Thank you for your comments. I can understand it. You know, from the mechanical concept, the shear modulus (G) can be represented by E/2*(1+v) for homogeneous isotropic materials, here E is young modulus, v is poisson ratio. So, can we decide G_over_E is equal to 1/2*(1+v) directly? Can we use 1/2*(1+v) to calculate kt/kn? Thank you so much.
Best Liqing At 2010-09-20 17:21:39，"Václav Šmilauer" <[email protected]> wrote: >> I have checked the relationship of the physical parameters and the >> required parameters in Yade. I am confused how to get the shear >> stiffness (tangential stiffness) from the poisson ratio and normal >> stiffness correctly. You know, according to the description in >> Vaclav's thesis page 52. I get the poisson ratio is not equal to the >> Kt/Kn (shear stiffness/normal stiffness) directly. However, in >> Ip2_2xCohFrictMat_CohFrictPhys, the shear stiffness is calculated just >> from Kn*poisson ratio. You know, in PFC theory, the users always need >> to give the shear stiffness directly. I know the poisson ratio (v) >> depends on the dimensionless ratio Kn/Kt. But I don't know how to get >> this formula (v=Kt/Kn). How to decide the coefficient? > >Hi, > >the way to compute Kn/Kt depends on the Ip2 functor in use. > >In the case of the Cpm model which you refer to (page 52), I was >directly specifying the Kn/Kt ratio in the CpmMat class (I call it >G_over_E, but G/Kt=E/Kn), the ElastMat::poisson is not used at all. > >Admittedly, the ElastMat::poisson is quite confusing, maybe replacing it >by the kt/kn ratio (ktDivKn) would be better. I think it is there for >historical reasons, though other people might know better. > >Cheers, v > > > >_______________________________________________ >Mailing list: https://launchpad.net/~yade-users >Post to : [email protected] >Unsubscribe : https://launchpad.net/~yade-users >More help : https://help.launchpad.net/ListHelp
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