Hello, I am using the UMAT code for sand hypoplasticity provided by Prof. Masin — https://soilmodels.com/download/plaxis-umat-hypoplas-zip/. I am simulating Axisymmetric condition in Abaqus. To check the results given by the […]
Archive for category: Constitutive Modelling
Htypoplastic Model in Miidas GTS NX

Views 1,468
Hello.. I am defining the hypoplastic parameters for Karlsruhe sand (found in a paper) using MIDAS GTS NX. In the software the a requesting (in addition of parameters) the number […]
Multi-objective analysis of the Sand Hypoplasticity model calibration

Views 260
I am happy to announce that our pre-print paper, “Multi-objective analysis of the Sand Hypoplasticity model calibration”, is available on researchgate (https://www.researchgate.net/publication/369199567_Multi-objective_analysis_of_the_Sand_Hypoplasticity_model_calibration) and Axive (https://doi.org/10.48550/arXiv.2303.07234). In this work, we study […]
Problem with SANISAND UMAT

Views 8,463
Hello all, I’m using the SANISAND UMAT I downloaded here for my research, the problem I found is it gives me wrong results in ABAQUS and INCREMENTAL DRIVER for element […]
What is an appropriate damping model for dynamic liquefaction analysis of tailings storage facility in FLAC?

Views 6,669
Has anyone had success simulating earthquake loading / dynamic liquefaction in a full-scale, plane-strain model of a TSF in FLAC2D/FLAC3D? The topic of damping is complex and the choice of […]
New features in Excalibre

Views 6,591
Hi all, We are happy to announce that the Excalibre team received support from the research grant GACR 22-12178S to further develop the calibration software, which is freely available at […]
Sanisand

Views 2,662
Hello, I am simulating soil and pile using Sanisand on Abaqus. I have problems with the analysis because of the value of the parameter 18. When I use small values, […]
SaniSand Model in Plaxis 3D

Views 15,957
Hello.. I am using SaniSand constitutive model, for the simulation of the behavior of onshore wind turbine using plaxis 3d. The dll file published in the website request the determination […]
The GA-cal software for the automatic calibration of soil constitutive laws

Views 5,489
I am happy to announce that our pre-print paper, “The GA-cal software for the automatic calibration of soil constitutive laws: a tutorial and a user manual”, is available on researchgate […]
Hello, I am writting to ask how to get the elastic modulus or undrained strength of the soil in the simulation model by using hypoplastic model in clay? Is there […]
Hi altruists, Hope all of you are doing well. I am looking for literature on the NorSand model, which considers the drained cyclic triaxial testing behavior. I have found a […]
Shear modulus degragation

Views 3,959
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 […]
FRIC code for clay hypoplasticity interface

Views 4,113
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
“Warning LNK4210” – hypoplastic clay UMAT

Views 2,899
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
Views 3,057
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

Views 3,125
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

Views 3,820
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

Views 4,543
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

Views 4,934
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

Views 3,847
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

Views 3,576
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

Views 3,954
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

Views 3,730
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 […]
Initial Stiffness of CU test in Masin’s 2014 Model

Views 3,410
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

Views 3,824
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 […]
MATLAB Code for Bounding Surface Plasticity Model

Views 3,448
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

Views 3,275
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)

Views 4,827
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

Views 4,472
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

Views 3,376
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

Views 3,921
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

Views 3,785
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

Views 3,422
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

Views 3,738
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

Views 3,836
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?

Views 4,893
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

Views 3,459
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

Views 3,218
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]

Views 3,231
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

Views 3,375
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. […]
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Recent posts
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Presentations from Prague Geotechnical Days 2023 including 29th Prague Geotechical Lecture by Yannis Dafalias 25.5.2023
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Problem in using Hypoplastic model for sand in Abaqus. 17.5.2023
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An error in the SANISAND umat runtime 8.5.2023
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Htypoplastic Model in Miidas GTS NX 25.4.2023
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set cavitation limit in ABAQUS/STANDARD when using SANISAND umat 2.4.2023
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FE formulation and software 25.3.2023
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Multi-objective analysis of the Sand Hypoplasticity model calibration 24.3.2023
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Problem with SANISAND UMAT 7.3.2023
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Prague Geotechnical Days 2023 (22nd – 23rd of May) with Prague Geotechnical Lecture by prof. Yannis Dafalias 28.2.2023
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What is an appropriate damping model for dynamic liquefaction analysis of tailings storage facility in FLAC? 10.2.2023
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Abaqus vs Plaxis – Local Convergence Tolerances 2.2.2023
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Zbraslav sand – Cyclic tests by Charles University 17.1.2023
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