====== NLSLAYER Command ======

NLSLAYER,<Num>,[curvefit],[B],[S],[refStrain],[Vis]

Define a nonlinear soil layer data set for the [[SASSI:SOIL]] module. The user can curve fit and not define any other properties for the curve. Otherwise, the user must define all of the curve properties. The default value for all of the arguments in this command is 0. 

The argument for this command are based on the following equation used for the hyperbolic stress-strain model for soils

{{ :com:nlslayer.png |}}

Where G_ois the elastic shear modulus, τ is the shear stress, γ is the shear strain, γ<sub>r</sub> is the reference shear strain (typically around 0.03%), β is a constant (typically around 1-1.4), and s is a constant (typically around 0.7-0.9), n is soil viscosity, and γ' is shear strain rate.


  * Num - soil layer number
  * curvefit - auto fit the curve.
    * 0 = not using curve fit
    * 1 = using curve fit
  * B - Beta 
  * S - S exponent
  * refStrain - reference strain
  * Vis - viscosity