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

ABAQUS modeling: Warning about unconnected regions when using hypoplasticity subroutine
Jasmine LokeshFinite Elements0 Views 627
I ran a simple 3D model with symmetry boundary conditions first using elastic material and then as hypoplastic using a subroutine. However, in the former case, I don’t get the […] 
Tochnog Professional Page moves
Dennis RoddemanFinite Elements1 Views 233
Hi All, Starting from Saturday January 26 2019 the Tochnog Professional page moves to http://www.tochnogprofessional.nl Best, Dennis Roddeman 
SANISAND umat issue
Philip AlkhouryFinite Elements1 Views 242
Hello everyone; I have implemented the Sanisand constitutive model (UMAT) in abaqus in the scope of performing a dynamic analysis on a 3D soilpile interaction problem. I have succeded in […] 
Boundary value problems for granular materials subjected to earthquake loading
MOHD SAQIBFinite Elements1 Views 137
Dear All, Hope you all well, I have been searching for some good publications on the Boundary value problems on Foundation system with granular materials subjected to earthquake loading or […] 
Problem with Hypoplastic Vumat use with CEL in Abaqus
Abdulkader ELHAJFinite Elements0 Views 186
Hello all, I am currently working on the FE modeling of anchors installation into the soil using the CEL analysis in Abaqus. I tried to use the hypoplastic vumat for […] 
Geostatic method for Abaqus/Explicit
Joe ChuFinite Elements2 Views 713
Dear all, I recently conducted a numerical simulation of pilesoil interaction. I digged a vertical hole and insert the pile into that with general contact. Due to many reasons, I […] 
Modeling cyclic undrained sandy soil triaxial test using ABAQUS
Shile DongFinite Elements3 Views 341
Dear all, I am trying to use Abaqus to modeling undrained cyclic triaxial test for liquefiable soil. I am wondering how could I applied the cyclic load. I should apply […] 
hypoplasticity model with Abaqus umat on Brno clay
mahdie masoudiFinite Elements3 Views 248
Dear all, I am a Ph.D. student at Kharazmi University. Recently I have been trying to simulate a triaxial compression test using the hypoplasticity model for clay using ABAQUS. The […]
Who is Online
No one is online right now
Search SoilModels Website
Recent posts
 Two postdoctoral positions in computational mechanics in Ben Gurion university and Ariel university, Israel, are available immediately 28.2.2021
 K0 determination Reloading using HP clay model 22.2.2021
 Seismic Liquifaction 11.2.2021
 Modelling cyclic loads in Tochnog 11.2.2021
 Soft soil model vs Soft soil creep model 8.2.2021
 Boundary value problems for granular materials subjected to earthquake loading 8.2.2021
 Guidance for a newbie 6.2.2021
 Modelling Ratedependent behaviour of clay [Urgent] 1.2.2021
 Postdoctoral Fellowship in computational geomechanics 27.1.2021
 USDM – Creep SCLAY1S 25.1.2021
 Hardening Soil Model in Abaqus 25.1.2021
 Effects of water content in sand in hypoplastic strength parameters 25.1.2021
Recent Comments
 Mehdi Joneidi on A problem of convergence from using Hypoplastic model in Abaqus
 Mehdi Joneidi on Boundary value problems for granular materials subjected to earthquake loading
 Mehdi Joneidi on Kadlíček, T. and Mašín, D. (2020). The strength reduction method in clay hypoplasticity. Computers and Geotechnics (in print)
 David Mašín on Kadlíček, T. and Mašín, D. (2020). The strength reduction method in clay hypoplasticity. Computers and Geotechnics (in print)
 Mehdi Joneidi on Kadlíček, T. and Mašín, D. (2020). The strength reduction method in clay hypoplasticity. Computers and Geotechnics (in print)
 Micha Van der Sloot on PM4Sand for Plaxis Download
 Eduardo Muguet on PM4Sand for Plaxis Download
 Sudipta Bhowmick on Subroutine of SANISAND model
 Sudipta Bhowmick on SANISAND (Dafalias and Manzari, 2004)
 Osama Dar on Guidance for a newbie
 Arie Koot on Seismic Liquifaction
 Emrecan Güven on Guidance for a newbie
 Osama Dar on Guidance for a newbie
 Gertraud Medicus on Guidance for a newbie
 Juan Tello on Clay hypoplasticity with strength reduction (umat and Plaxis dll).
 Juan Tello on UMAT Implementation of Sand Hypoplasticity by UIBK
 Micha Van der Sloot on PLAXIS
 Micha Van der Sloot on USDM – Creep SCLAY1S
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