Modeling soil in Ansys? 1

[ansysfreak]

Hi,

I have a question about 3d modeling soil in ansys.
I studied the help menu of Ansys, i know al about the material model of soil (Drucker en Prager theory). White this theory you can model soil under presser. But what i don't know is how to model the sliding of the soil(yield).

Can you tell me how the model soil?

Garry

 

[jiligeo]

Dear Garry,
For your problem, Structural material properties must be input as isotropic elastic linear. Young's modulus (EX) and Poisson’s ratio (PRXY or NUXY) must be input as constant materials. Poisson's ratio
defaults to 0.3 and should not be equal to or greater than 0.5.
you have to choose Drucker-Prager (DP) in non-linear, inelastic, non-metal plasticity models.

The input data consists of three constants:
??the cohesion value (must be > 0)
??the angle of internal friction
??the dilatancy angle.
The amount of dilatancy (the increase in material volume due to yielding) can be controlled
with the dilatancy angle. If the dilatancy angle is equal to the friction angle, the flow rule is
associative. If the dilatancy angle is zero (or less than the friction angle), there is no (or less
of an) increase in material volume when yielding and the flow rule is non-associated.
The behaviour of soil is elastic until the stress level recive to a limit which is defined with this equation
f (I1,J2) = ??I1 + ?J2 – k = 0
and the constants ? and k are related to C and ? with below equations:
??= 2 sin ??/ [(3 – sin ?) ?3]
k = 6 c cos ??/ [(3 – sin ?) ?3]