### Estimating density and Poisson’s ratio for use in FEM analys

Posted:

**Fri Jun 15, 2012 12:34 pm**Hi,

I have undertaken MASW testing and ultimately want to replicate the soil conditions with high accuracy for an explicit finite element analysis. Despite this, I find I get quite different Dinver ground profiles based on my specified input parameters.

I have read on the forum that people recommend keeping density and poisson’s ratio constant for all layers, but ideally I would like something more realistic/accurate than this (FEM requires density, Poisson and Young’s modulus for each layer).

1. Are there any recommendations for maximising the accuracy of density/poisons ratio for each layer? I have deliberately been creating more layers than I believe to exist and allowing all 4 variables to vary at each layer (with only Vp linked to Vs)…is this likely to deliver more accurate soil properties (if I run enough model scenarios)? Also, should density be linked to Vs?

2. Is it possible to get a ground profile plot for poisons ratio (like that available for Vs, Vp and density)?

3. After obtaining material properties using Dinver, would forward modelling using FEM be the best approach to verify/tweak the layer material properties?

Many thanks,

David

I have undertaken MASW testing and ultimately want to replicate the soil conditions with high accuracy for an explicit finite element analysis. Despite this, I find I get quite different Dinver ground profiles based on my specified input parameters.

I have read on the forum that people recommend keeping density and poisson’s ratio constant for all layers, but ideally I would like something more realistic/accurate than this (FEM requires density, Poisson and Young’s modulus for each layer).

1. Are there any recommendations for maximising the accuracy of density/poisons ratio for each layer? I have deliberately been creating more layers than I believe to exist and allowing all 4 variables to vary at each layer (with only Vp linked to Vs)…is this likely to deliver more accurate soil properties (if I run enough model scenarios)? Also, should density be linked to Vs?

2. Is it possible to get a ground profile plot for poisons ratio (like that available for Vs, Vp and density)?

3. After obtaining material properties using Dinver, would forward modelling using FEM be the best approach to verify/tweak the layer material properties?

Many thanks,

David