asdeasoft.net

Dear STKO team,

First of all I wish you a happy new year.

I am reaching out to kindly ask your insight about the following point:

So I just modelled a 2D model of soil (1mX1mX1m) and did run a cyclic loading test, the analysis is running fine as following:
I had given as input of Normalized modulus reduction with respect to strain :

Strain (%) G/G0
1e-05 0.98
3e-05 0.95
0.0001 0.85
0.0003 0.6
0.001 0.3
0.003 0.15
0.01 0.06

with refshearModul equal to 1.35e+08, then from the results of the first cyclic loading test (displacement Vs shear force) , I did selected the first cycle (tiny displacments) , from where I derived the Shear Modulus G0 got the value of 7.00e+07 so the input stiffness is quite 2 times higher then the output + I also extend the preprocessing and derive the G/G0 and strain and it is quite different as you can see in the figure below:
would you please help me to identify where is my issue ? the model as well as the results are in the following file.
Thank you,

Zouatine

You should revise your model.
You used absorbing boundaries that are not correct in this example.
You should use equalDOF on the vertical sides, to impose a shear motion.
Optionally (if you discretize your quad with more that 1 element) you need an equalDOF on top to avoid rotaiton (Equal UY)