I tried to model sample of triaxial test in Abaqus program. I used hypoplastic subroutine. The parameters used in hypoplastic model was Hochstetten sand the given in website “https://web.natur.cuni.cz/uhigug/masin/plaxumat/node5.html”.
The used steps of analysis were as;
– First step is for applying confining pressure in the sample.
– Second step is for consolidation process (dissipation of excess pore pressure).
– Third step is applying deviator stress (axial stress).
The analysis was completed in first and second steps, but it was aborted in third step (note: the deviator stress was small).
Could anyone to solve this problem?
The boundary conditions are shown in attachments figures.
Modeling of triaxial test sample by using hypoplastic subroutine
Related Articles

DIANA with monopile follows Blum theory saving 10 m of length
Ab van den bosFinite Elements0 Views 165
Where the client was forced to make all his horizontal loaded Dolphins (piles) 10 m longer we could trustworthy proof that this actually was not necessary saving millions of cost […] 
SANISAND umat issue
Philip AlkhouryFinite Elements1 Views 205
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 […] 
PM4Silt software
Daniel ValenciaFinite Elements1 Views 244
Hello everybody, Does somebody know a FEM Software with the implementation of PM4Silt model’s routine? I mean, one different from FLAC. Thanks for your help. 
Problem with Hypoplastic Vumat use with CEL in Abaqus
Abdulkader ELHAJFinite Elements0 Views 96
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 […] 
Hypoplastic model for thermal cycles (Abaqus)
Chiara IodiceFinite Elements2 Views 435
Dear all, I’m using the UMAT file in which the hypoplastic model for thermal cycles is implemented. In the Abaqus input file I have added the two lines necessary to […] 
Presentations on hypoplasticity applications, D. Mašín, NGI 2017
David MašínFinite Elements0 Views 1,733
Based on some requests, I share here two presentations on hypoplasticity applications. One is related to simulation of various boundary value problems, the other focuses on simulation of cyclic and […] 
Issues with Tochnog Professional not posting groundflow velocities
Fernando LorenzoFinite Elements3 Views 100
I have been a =n user of the open source version of Tochnog for since 2004. I have been one of the maintainers and have contributed to the capabilities of […] 
problem with sanisand umat
yousef zandFinite Elements8 Views 277
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 […]
Who is Online
No one is online right now
Search SoilModels Website
Recent posts
 HP clay subroutine in Plaxis 30.10.2020
 Modeling cyclic undrained sandy soil triaxial test using ABAQUS 27.10.2020
 UMAT for NorSand 27.10.2020
 Problem with Hypoplastic Vumat use with CEL in Abaqus 27.10.2020
 Interpreting results of sand hypoplastic model with Abaqus VUMAT 23.10.2020
 Interpreting results of sand hypoplastic model with Abaqus VUMAT 22.10.2020
 Skin friction along depth of pile 18.10.2020
 SANISAND pilesoilinteraction ABAQUS 13.10.2020
 Issues with Tochnog Professional not posting groundflow velocities 12.10.2020
 Question on the Matlab driverhypoplastic models 28.9.2020
 a question on the clay hypoplasticity model with Abaqus umat 26.9.2020
 UMAT Code for Modified Cam Clay model 22.9.2020
Recent Comments
 Yang Liu on Download package of a complete dataset “Karlsruhe fine sand – Cyclic tests (T. Wichtmann)”
 Alireza Mojtahedi on Schädlich, B. (2012) A Multilaminate Constitutive Model for Stiff Soils., PhD Thesis, Graz University of Technology [Thesis]
 Wang Shun on Modeling cyclic undrained sandy soil triaxial test using ABAQUS
 Sajjad Shakeri on PM4Sand for Plaxis Download
 David Mašín on HP clay subroutine in Plaxis
 Muhammad Shakeel on HP clay subroutine in Plaxis
 Eric Sun on Factor of safety in Plaxis 3D using hypoplastic model for sand
 Fernando Lorenzo on Issues with Tochnog Professional not posting groundflow velocities
 Joshua Schorr on Sand and clay standard datasets
 Maciej Ochmański on Issues with Tochnog Professional not posting groundflow velocities
 David Mašín on HP clay subroutine in Plaxis
 Shile Dong on UMAT Code for Modified Cam Clay model
 Hans Henning Stutz on Interpreting results of sand hypoplastic model with Abaqus VUMAT
 Maciej Ochmański on Issues with Tochnog Professional not posting groundflow velocities
 Liu Junxin on SANISAND for FLAC3D Download
 Lee Jae Sung on SANISAND umat issue
 Benbo Sun on SANISAND pilesoilinteraction ABAQUS
 Shen Wang on Clay Hypoplasticity (Mašín, 2014)
Dear Neif,
– Please first check the results of the first two steps to see whether they are sensible, even better you may compare them with results of some element test drivers from SoilModels: this will consfirm that you have properly set the parameters.
– Then make sure you subdivide the shear stage into many small steps. It is not clear from your post whether you use intergranular strain or not. In particular the istrain version may require small step size as there is significant stiffness change during loading.
– If the simulation crashes, it should produce error file (something like fort.1) where some crash information should be given. You may also see some messages in log files of Abaqus project, which could help to find the source of the problem.
Regards David
Dear Dr. David
– The intergranular strain concept was used with value δ=0.00001.
– The magnitude of axial stress that used at third step is 1.0 kPa.
– The type of steps is soils (transient)
– The time period and increment size of third step were 0.1, and 0.001 respectively.
In term of the results of analysis of first and second step, there was no change in void ratio.
the analysis is incomplete in third step.
I need for helping for this problem please?
Dear Neif,
It seems that the second step was failed if there was no void change.
Have you ever try a triaxial test with only one element?
I prefer to start with elementary tests without intergranular strain
Regards
Dear Wang
Thank you very much for your helping.
I considered your noting for modeling sample without intergranular strain, but the analysis was incomplete in step 3 (applying axial stress).
In term of void ratio, i mean that the void ratio in first step (applying confining pressure) is equal to the void ratio in second step (consolidation step). on other word, the value of void ratio is constant in first and second steps which is equal as the void ratio that set in initial condition.
Hi,
just a couple of observations:
Why are the bc in the lower side fixed in vertical and horizontal direction? You only need to fix them in the vertical direction (they must be free to move in the horizontal direction specially in the consolidation phase).
I would advise you to model this first with a 2D model in axial symmetrical conditions and without intergranular strain. Start with 1 element and then you can slowly increase the number of elements or even dimensions if you need it and afterwards add with the intergranular strain parameters.
If the void ratio did not change it means there is no volumetric deformation. This might be the case if the confinig phase is not modelled correctly (check if the stress state changes correctly) or if the sample is able to deform (drained conditions)
Good luck.
Dear Oscar
Thank for help. I considered your noting, but i have the same problem.
When Hypoplastic model were replaced by MohrCoulomb and elasticity, the analysis was completed and there were volume changes throughout steps.
When Hypoplastic model were used, and there were no drainage conditions at top and bottom of sample, the analysis was completed and here were no volume changes throughout steps.
Is there parameter in hypoplastic umat subroutine or in hypoplastic model (12 parameters) that control or prevent the volume change of the sample of triaxial?
I modeled initial void ratio as uniform value. If are there other method to model initial void ratio (predefined field), provide me this method please.
Hi Naif,
not to my knowledge. I have worked with the von Wolffersdorf hypoplastic model without a problem. I am thinking the problem lies in assigning the initial void ratio. You can check this value in Abaqus output by looking at the system defined variables (sdv).
Good luck solving your problem