Hello all, I am using the clay hypoplsticity model in Abaqus. As shown in the picture, I have to construct the stiffness desegregation curve to calibrate the R value. Can […]
Archive for category: Constitutive Modelling
FRIC code for clay hypoplasticity interface

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1,571
Dear Prof Stutz and Prof Mašín, Is FRIC code for clay hypoplasticity available? If yes, could you please provide me with the link to download FRIC? Thank you Haran
Hypo-umat sand

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593
Dear professor and friends: At present, I am using the UMAT program downloaded in the forum. I have not made any modification to the downloaded program itself to simulate a […]
Hypo-umat sand

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149
Dear professor and friends: At present, I am using the UMAT program downloaded in the forum. I have not made any modification to the downloaded program itself to simulate a […]
Hello Everyone, I am using the UMAT code for clay hypoplasticity provided by Prof. Masin — https://soilmodels.com/download/plaxis-umat-hypoplas-zip/ I made a test model in Abaqus2020 and applied the umat code (umat_hcea.for). […]
Input files for element tests for hypoplastic clay/sand UMAT
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562
I’m interested in using the model for simulating excavations in clay, where the small strain modulus is important, and the analysis has to be transient consolidation. It would be helpful […]
Combining Hypoplastic-sand and Hypoplastic-clay in one UMAT file

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573
Hi everyone, i have combined both Hypoplastic sand and clay umats in one umat ( to use for example in the case of multilayered soil medium made of clay and […]
I have a UMAT of Mohr Coulomb with no hardening, where i have to define SSE (specific strain energy) and SPD (specific plastic dissipation). Any idea?
Papers on Excalibre

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1,361
Hi all, Details of Excalibre software (https://soilmodels.com/excalibre) functionality and calibration procedure have been published in two papers, which are now available online at the webpages of publisher (https://link.springer.com/article/10.1007%2Fs11440-021-01441-0 and https://link.springer.com/article/10.1007%2Fs11440-021-01435-y). […]
Abaqus UEL Hypoplasticity

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1,746
Dear all, I want to implement a new user element using the UEL subroutine. To simulate dynamic cases, one has to define the mass, damping and stiffness matrix then build […]
Hypoplastic UMAT & Void Ratio

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2,398
Hi all, Can anyone give a clarification on the material property (parameter 22) in the hypopplasticity umat for clay on Abaqus. My understanding is that these parameters are defined as […]
Modelling TX monotonic compressive test with ABAQUS and SANISAND – not working

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1,238
I am trying to reproduce a TX monotonic, compressive test on a sand by using a 1-element, axisymmetric ABAQUS FE model, assigned to a SANISAND material. For this purpose, I […]
Getting started with UMAT for Hypoplastic clay model in ABAQUS

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1,033
Hello All, I am getting started with implementing UMAT for soil model in ABAQUS. I am planning to use Hypoplastic clay constitutive soil model to simulate the triaxial tests. I […]
consistent tangent stiffness calculation in hypoplasticity sand UMAT

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1,354
Dear all, Thanks for hypoplasticity sand UMAT provided by Prof. Masin. During studying hypo sand UMAT, I am encountered with a question about consistent tangent stiffness calculation. subroutine ”perturbate_h“ seems […]
Dear forumers: Thanks to hypoplasticity sand UMAT provided by Prof. Masin — https://soilmodels.com/download/plaxis-umat-hypoplas-zip/. But during studying above sand UMAT, I found that the stress order may be incorrect. Because stress […]
ALERT doctoral school on constitutive modelling – hands on session triax input files

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1,218
ALERT doctoral school on constitutive modelling is happening right now. The school lecture notes are available at the website of ALERT geomaterials (http://alertgeomaterials.eu/publications/) Below you find triax input files for […]
Hi, I am using Hypoplasticity model with explicit asymptotic boundary surface proposed by Prof. Masin in 2014. In this model, parameter ‘nu’ controls initial stiffness in CU test. But when […]
CONSTUTUTIVE MODELLING

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1,365
Can SANISAND version given in soil model work well for cyclic simple shear test ?
Hi Admin, I have been using hypoplastic subroutine supplied by this website. It works well in ABQ6.14 and ABQ2017. However, recently I have to upgrade to ABQ2021 due to an […]
Dear Altruists, I just wanted to learn the bounding surface plasticity theory with coding. Does anyone have any code (written in MATLAB) for the Bounding Surface Plasticity model? Could you […]
Non convergence problem in abaqus using hpoeca Clay Hypoplasticity in slope model

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693
hello everyone! based on the strength reduction method in clay hypoplasticity, firstly, I used two steps belong to the static_general, the first step is impose a gravity load, and not […]
Anyone has any reference to writing UMAT file for Poro linear elastic properties or what constitutive equations have to be solved to do the same. Any help would be appreciated […]
Cyclic/monotonic direct shear test (matlab driver)

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2,219
Hi everyone, i am trying to simulate DSS/cDSS test in drained/undrained conditions and I was wondering how the constraints matrices should be ? while it is easy to understand how […]
Convergence issue of unload of clay consolidation in Abaqus

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1,881
Hello, I was trying to simulate the unloading process of clay consolidation in Abaqus using clay hypoplasticity umat (https://soilmodels.com/download/plaxis-umat-hypoplas-zip/). But I had a convergence issue showing in Fig.1. The model […]
Convergence issue of unload of clay consolidation in Abaqus

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920
Hello, I was trying to simulate the unloading process of clay consolidation in Abaqus using clay hypoplasticity umat (https://soilmodels.com/download/plaxis-umat-hypoplas-zip/). But I had a convergence issue showing in Fig.1. The model […]
PLAXIS 2D Embedded Pile Row

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1,131
PLAXIS 2D require a “Lateral Resistance ” for the embedded pile row. The manuals are not very clear as to what the resistance represents? Is it on friction ( similar […]
Cyclic Triaxial Test

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1,064
Dear All, I am using ISA+HP model in my research and I have encountered some problem when looking into cyclic triaxial test for single element. The target model was selected […]
matlab driver

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867
Hi everyone. When i try to run the matlab driver I get the following error, how can i sove it ? (The constructor for class ‘update’ must return only one […]
Dear all, I have a question about Hypoplasticity for sand model, i am having trouble to understand about how to calibrate the mr parameter ? Since no formula is provided […]
UMAT Code for Clay Hypoplasticity

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1,150
Hello Everyone, I am using the UMAT code for clay hypoplasticity provided by Prof. Masin — https://soilmodels.com/download/plaxis-umat-hypoplas-zip/ I made a oedometeric test model in Abaqus2018 and applied the umat code […]
UDSM PLAXIS

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1,164
I implemented a unified dynamic soil model, but PLAXIS doesn’t calculate any strains, and it prints zero (or some times NaN amounts) into a text file. I’d like to know […]
How can I solve the error in Abaqus mentioned below?

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1,419
I am using SANISAND to simulate a triaxial compression test under monotonic loading. But every time my simulations break and give the same message “Abaqus/Implicit Packager exited with an error […]
Guidance to newbie on how to calibrate a constitutive model

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956
Hi! I am studying the behavior of kaolin clay under cyclic loading. The strain rate is kept at such that undrained behavior is maintained. I want to use an advanced […]
K0 determination Reloading using HP clay model

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848
Hi Prof. Masin , It is related to my previous post. Sorry to bother you again. I simulated Oedometer test in Plaxis as well as centrifuge reloading (using HP clay […]
Soft soil and soft soil creep model both include time while performing the analysis. What is the difference between both of them.
Modelling Rate-dependent behaviour of clay [Urgent]

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759
Using PLAXIS, how to model rate dependent behavior of clay. This is to show the viscous behavior of the soil. Thank you in advance
USDM – Creep -SCLAY1S

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833
I have the license, but can’t login as it is a server license. In order to access this model, i need the .dll file. Can anyone help me with this. […]
Hardening Soil Model in Abaqus

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1,419
Is there Hardening Soil Model in Abaqus?
Effects of water content in sand in hypoplastic strength parameters

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739
Dear All, I am currently using the hypoplastic model for gran materials from Prof. von Wolffersdorff to simulate soil excavations in a context of large deformations. I have been searching […]
Hello all, I am trying to implement boundary surface plasticity using Bardets model in MATLAB. But i am obtaining negative values for q and Dep. Any help in this regard […]
SANISAND 2008 Model

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831
Hello Everyone, Can anyone have umat available for SANISAND 08 (Simple anisotropic sand plasticity model)?. Paper authored by Taiebat and Dafalias. They have used a closed type yield surface. Regards […]
Issues in getting the negative values of q (mean deviatoric stress) while simulating cyclic triaxial test in ABAQUS using SANISAND subroutine.

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970
Hello Everyone, I have been trying to simulate the cyclic triaxial test using the SANISAND04 subroutine. When I plotting the stress path (p-q plot), I am getting only the positive […]
UMAT for NorSand

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1,147
Dear all, I am pretty new in coding and using Abaqus. I have trouble with coding the UMAT for NorSand. If any of you have any good references, please share […]
Interpreting results of sand hypoplastic model with Abaqus VUMAT

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1,195
Dear concern, Recently i have modelled the soil pile interaction using Abaqus CEL method. The hypoplastic behavior of the soil is model using user subroutine VUMAT. The properties of the […]
SANISAND pile-soil-interaction ABAQUS

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1,086
Hi everyone: I am trying to use SANISAND as the constitutive model of soil, and use ABAQUS software to simulate pile-soil interaction. First step is “Geostatic”, the second step is […]
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Recent posts
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Shear modulus degragation 12.5.2022
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FRIC code for clay hypoplasticity interface 23.4.2022
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Hypo-umat sand 18.4.2022
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Hypo-umat sand 18.4.2022
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Using pore fluid-stress element in SandSand 9.4.2022
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“Warning LNK4210” – hypoplastic clay UMAT 8.4.2022
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Prague Geotechnical Days 2022 with Prague Geotechnical Lecture by prof. Cino Viggiani 7.4.2022
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Micropiles load tests database 26.3.2022
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DIANA 10.5 new features 10.3.2022
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Input files for element tests for hypoplastic clay/sand UMAT 6.3.2022
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Combining Hypoplastic-sand and Hypoplastic-clay in one UMAT file 2.3.2022
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UMAT code for Unsaturated soil modes 19.2.2022
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