Modify ISoil Inputs

[hoffwm]

Currently, shear wave velocity is not a recognized input parameter for ISoil. The user is required to determine the shear and bulk modulus of the material beforehand. The shear modulus, G =rhoV^2. where rho is density and V is shear wave velocity. The bulk modulus, K=(2G(1+nu)/(3(1-2nu)), where G is the shear modulus and nu is Poissons ratio. The user should be able to input shear wave velocity, then bulk and shear modulus can be calculated internally using velocity, density, and poissons ratio.

Also, several of the ISoil material inputs for material property values need to be controllable to enable Monte Carlo simulations, inlcuding: Poissons Ratio, density, and shear wave velocity.

[hoffwm]

@aeslaughter I am not quite sure how to share my branch with you... the branch is called mc_site_response on git@github.com:hoffwm/mastodon.git

[cbolisetti]

@hoffwm. The Bulk modulus input was not necessary and is removed now. I am still keeping the inputs as shear modulus and Poisson's ratio since those are the inputs that are most commonly used.

[hoffwm]

@cbolisetti Okay thank you!