Dear all,
I’m trying to model multilayer soil in abaqus. To use the SaniSand umat in model I use the following parameters but no plastic strain at all. The unit system used is us(in). Are the input parameters incorrect?
Could anyone kindly help me solve this problem? Thanks a lot!.
problem with sanisand umat
Related Articles

change the friction angle with the plastic strain in Abaqus following mohr coulomb model.
Majid FetratiFinite Elements1 Views 483
Hi, I want to change the friction angle with the plastic strain in Abaqus following mohr coulomb model. Vermeer and de Borst (1984) proposed an equation for frictional hardening and […] 
Calibrate hypoplastic model
sahar saabFinite Elements2 Views 182
I am trying to calibrate my sand using Excalibre. I tried some triaxial element tests using Abaqus. However the results are different between Excalibre and Abaqus. 
Hypoplastic model for thermal cycles in clay (Abaqus)
Sherif GomaaFinite Elements2 Views 266
Dear all, I’m using the UMAT file in which the hypoplastic model for thermal cycles is implemented. I have done some runs for an axisymmetrical model for a single energy […] 
new hypoplasticity laws in Tochnog Professional
dennis roddemanFinite Elements0 Views 201
The 2014 Masin hypoplasticity for clays has been implemented in Tochnog Professional under guidance of Dr. David Masin. This implementation includes structure, intergranular strains and visco effects. Extensions to the […] 
Tochnog Professional Page moves
Dennis RoddemanFinite Elements1 Views 197
Hi All, Starting from Saturday January 26 2019 the Tochnog Professional page moves to http://www.tochnogprofessional.nl Best, Dennis Roddeman 
How to model the settlement in soil due to water drawdown.
Guru PandaFinite Elements3 Views 420
Which software has the feature to model soil settlement due water drawdown? 
EasyTochnog input file generator
Dennis RoddemanFinite Elements0 Views 191
Hi All, Tochnog Professional now has an EasyTochnog extension, see http://www.tochnogprofessional.nl/easy_tochnog/page.php. With simple input data like pile diameter, pile length, slope geometry, sheet pile data, etc. a complete Tochnog Professional […] 
A problem of convergence from using Hypoplastic model in Abaqus
Joe ChuFinite Elements4 Views 89
Dear all, The sand hypoplastic model has been used to simulate the interaction between soil and pile. However, there is a bad convergence in the process of calculation. When I […]
Who is Online
No one is online right now
Search SoilModels Website
Recent posts
Recent Comments
 Hashmi Sohawon on Hypoplastic UMAT error ABAQUS
 Shuntao Fan on Clay and Sand hypoplasticity UMAT and Plaxis implementations, including UMATPlaxis interface
 David Mašín on finite element modeling of ISAHP for sand material
 Hans Henning Stutz on Clay and Sand hypoplasticity UMAT and Plaxis implementations, including UMATPlaxis interface
 Shuntao Fan on Clay and Sand hypoplasticity UMAT and Plaxis implementations, including UMATPlaxis interface
 Piotr Kowalczyk on Sanisand model
 Hashmi Sohawon on Hypoplastic Intergranular vs Triaxial Data
 David Mašín on Hypoplastic Intergranular vs Triaxial Data
 Zeynep Merve Ürkmez on PM4Sand now available in PLAXIS 2D
 Joe Chu on Geostatic method for Abaqus/Explicit
 Piotr Kowalczyk on problem with sanisand umat
 Arie Koot on problem with sanisand umat
Hey Yousef
The parameters look generally ok. Rather close to the original calibration of Dafalias & Manzari for Toyoura Sand. If you are using US units check if your G0 parameter, which is indeed unitless, is still 125 or is it different value.
Good luck
Piotr
Hello
Thank you for replay
G0 is a dimensionless constant, but by changing its value, PE is STEEL equal to zero.
Hey Yousef
As mentioned by Arie, PE is not calculated by the umat. It is calculated only by the constitutive models implemented in Abaqus. If you want to see if plastic strains occur from the umat, then read umat carefully and try to ask for your own output in log file. I am not sure if you can ask for the actual value of the plastic strain.
Piotr
What do you mean “no plastic strain”?
Sanisand umat does not calculate plastic strain: it is a kinematic hardening model with one backstress.
It only needs and calculates plastic strain rate.
Thank you for replay
PE in visualization always is zero
though with chang in load and b.c
is this correct؟
Or do you mean you miss plastic strain input?
Hardening behavior is described by the hardening parameters
i set depvar=36
and check pe in field output in step
and select umat in job
Something else needs to be done؟
select pe has no use: it is not calculated by sanisand.
You can select SDV output but then you get all 36 statevar. (you cannot select a few)
It will make your odb larger but it gives you more information.
c 1 … alpha_11 back stress, orientation of yield surface cone
c 2 … alpha_22
c 3 … alpha_33
c 4 … alpha_12
c 5 … alpha_13
c 6 … alpha_23
c
c 7 … void void ratio
c
c 8 … Fab_11 fabric tensor z
c 9 … Fab_22
c 10 … Fab_33
c 11 … Fab_12
c 12 … Fab_13
c 13 … Fab_23
c
c 14 … not used
c
c group 2: memory variables for shear reversal (SR) and other purposes
c
c 15 … alpha_sr_11 alpha value at stress reversal points (discrete update)
c 16 … alpha_sr_22
c 17 … alpha_sr_33
c 18 … alpha_sr_12
c 19 … alpha_sr_13
c 20 … alpha_sr_23
c
c 21 … not used
c 22 … not used
c 23 … not used
c 24 … not used
c 25 … not used
c 26 … not used
c 27 … not used
c
c 28 … not used
c
c group 3: variables saved for post processing or other purposes
c
c 29 … pore excess pore pressure (undrained case)
c 30 … p mean effective stress
c 31 … q deviator stress
c 32 … z Lode parameter (cos(3theta))
c 33 … dtsub suggested size of first time substep
c 34 … nfev number of function evaluation
c 35 … not used
c 36 … not used
c