I am happy to announce that our pre-print paper, “Calibration of the von Wolffersdorff model using Genetic Algorithms”, is available on researchgate: https://www.researchgate.net/publication/342198062_Calibration_of_the_von_Wolffersdorff_model_using_Genetic_Algorithms. In this article, we propose a novel […]
Hi, I am new to Tochnog and really appreciate the open source modeling chain (gmsh->Tochnog->paraview). So far, I’m only familiar with commercial codes, e.g. Abaqus. I actually deal with metal […]
dear user hello i intend to build a numerical model using flac3d 6 software i build the geometry with extrusion pane and set all values for pile – soil interaction […]
Hello, I want to use the hypoplastic model for granular materials downloaded from https://soilmodels.com/download/plaxis-umat-hypoplas-zip. The UMAT file umat.for is the model for sand. I followed the instruction https://web.natur.cuni.cz/uhigug/masin/plaxumat/node5.html. I have […]
Hello, Is there any constitutive model for sand which can simulate the number of cycles to reach the critical state. I used the SANISAND model but it is not promising. […]
Hi, Does someone know if sanisand implementation has been used in a boundary value problem for slope? do you have any references? Thanks very much!
Hello guys. I just tried to calibrate on soilmodels. I´ve done three CIUP-REC-test plus one oedometric test. As you can see in the images, that there is still something quite […]
Hi all Just a short question on the modification of the intergranular strain concept proposed by Wegener & Herle (2014) to limit strain accumulation. In terms of the numerical implementation […]
How to implement this Hypoplastic Interface Model into ABAQUS combined with the existing hypoplastic model subroutine
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Hello: I’m a post-doc at the University of Nottingham, and I’m using the hypoplastic model to simulate the centrifuge tests we did. The research area is related to soil-pile interaction. […]
Implimentation of SANISAND constitutive model in ABAQUS/Standard for a soil-monopile interaction
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Dear all, I am trying to model soil-monopile interaction (3D) in ABAQUS/Standard in order to perform subsequently a cyclic and dynamic analysis. For the soil I am using the SANISAND […]
Hi David, Can you please provide some comments on the ability of the Hypoplasticity model with intergranular strain concept to model the effects of recent stress history on the clay […]
Problems with the UMAT subroutine check_parms_DM of the SANISAND constitutive model
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Where can I find the source of the content in the picture below in the UMAT subroutine check_parms_DM of the SANISAND constitutive model?
Dear all Is the basic Hypo-Plastic model (Wollffersdorff’s model) suitable for 3D models? Can I analyze 3D models with this UMAT? (https://soilmodels.com/download/umat-hyposand-uibk/) Thank you Sobhan
Modified Cam clay model now supported in automatic calibration software ExCalibre
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Free SoilModels automatic calibration software ExCalibre, available at, https://soilmodels.com/excalibre/, now supports Modified Cam clay model. This is both for laboratory test simulation as well as for automatic calibration. We hope […]
Hi David, I have reproduced some single elements test on ABAQUS using the UMAT to compare with Triax Hypoplasticity. So far, my stiffness curve (q vs ea) and my stress […]
Hi all, I wanted to ask if anyone has experienced this error before when running the Hypoplastic UMAT (umat_hcea.for) on Abaqus? “Abaqus Error: The executable standard.exe aborted with system error […]
Is the Sanisand constitutive model 3 dimensional? Could it be used for dry sand cases using C4D8 elements? (drained sand) Is it possible to apply it in a dynamic implicit […]
Hi David, I am trying to reproduce some Triaxial data from Coop et al. (1995) using the Hypoplastic Model with Intergranular Strain Concept on Triax. So far, I cannot get […]
Dear community I have 4 Question in implementation of Hypo-sand Umat in ABAQUS could someone kindly explain? 1. I checked the Umat file from (https://soilmodels.com/download/plaxis-umat-hypoplas-zip/) and i understand this subroutine […]
Dear all I’m studying hypo-plastic constitutive law from beginning concepts I traced concepts successfully until i faced **rate independent topic** i read this topic in the prof. Wolfgangs paper (hypo-plasticity […]
As a beginner to soil constitutive modelling, I am learning the hypoplastic models by reading the matlab drivers. I am confused with the matlab file f_hyp.m in the model hypo_camclay. […]
hi every one i’m using abaqus 2017 and i want to implement Hypo-sand to my Biaxial model (2D) and before all, i linked abaqus and fortran successfully my question is […]
Good evening, everyone. I find it difficult to apply equations (13) and (14) of Herle’s publication “Determination of parameters of a hypoplastic constitutive model from properties of grain assemblies”. As […]
Hi everyone I am writing a code for a model in the UDSM format for Plaxis. I already have the “*.dll” files, but when I run the soil test I […]
Hi all, I wanted to share these results to show that the use of the hypo clay model does in fact give more realistic undrained stress paths for clays on […]
Hi Prof. David, I have obtained these results in that attached picture using Triax and got confused when seeing that an isotopically normally consolidated sample does not follow a trend […]
Dear PhD, I am studying roller vibrations on sandy soil models with vumat. Can PhD give me the subroutine model and input parameters of objects for reference? Unit of the […]
Hi all, After successfully testing a linear elastic Umat on Abaqus, I am now trying to test the Hypoplastic model Umat. I intend to carry out a drained triaxial single […]
Dear Community, I want to include a non-local regularization technique in the built-in Mohr-Coulomb model of abaqus to capture the strain-localization effects. I am trying to find the original VUMAT […]
Hi everyone When I use sanisand model in abaqus , This error is seen Can anyone help? Other subroutines work well for me Is it possible for my input parameters […]
hello every one i have a problem with abaqus subroutine can i use hypoplastic umat file that prepared for palxis in this website in abaqus? or the files must be […]
Hello everyone, I have just a general question how people approach the problem of spurious oscillations generated in dynamic analysis when using nonlinear soil constitutive models. I understand sometimes numerical […]
Hello all, i did the automatic calibration for the Dobrany and Motol sand and tried to model the soil tests also in Plaxis and then to compare both. For the […]
Dear community, I’m interested in constitutive models that can handle strain-rate effects for HSR on sands for simulating free fall penetration. I would appreciate any help. Do you know any […]
Dr. Masin I have downloaded the most recent dll for Plaxis that includes the HypoPlastic model for Clays that you developed. I see two new parameters (Gvh0 and n), both […]
if you could please let me know whether Is there any constitutive model exist for capturing cyclic response for cemented materials just like cemented sand and gravelly soils.
Hi everyone, I work on soil constitutive models and I want to compare soil behaviours with various constitutive models but I can’t find Lade umat in the .for format. Can […]
Hello all, i have another question regarding the calibration process. Why do the initial void ratios differ between the input file and the output from excalibre? What is done during […]
Dear All, I am using sand hypoplastic model in my research and I have encountered some problem when looking into cyclic simple shear test in the range of small strains. […]
Dear Prof. David Mašín Greetings I would like to discuss with you an issue. I have a problem in my simulation on ABAQUS. The problem in the simulation results is […]
Hello all, According to my last post some weeks ago I now have translated the laboratory data from engineering strain to true strain with the following formula: epsilon(true)=ln(1+epsilon(engineering)). I compared […]
Greeting Everyone, I’m a new user of ABAQUS. I’m trying to simulate soil dynamic compaction by Cap model. I simulated the blow by half sinusoidal wave. Although I used Cap […]
Dear all, I’m facing trouble in calculating NO. 16 parameter in the UMAT for sand hypoplasticity by Dr. Masin, any help will be really appreciated especially with an example. Best […]
Hi all, Can somebody recommmend a good detailed guide for the procedures required to link ABAQUS 6.14 to Intel Fortran Compiler and Microsoft Visual Studio? Thank you, Hashmi
Are the slides in regards to Stiffness Anisotropy for Clay Hypoplasticity for the PhD course available online? The available document {Mašín, D. (2015) Part 4: Determination of material parameters, PhD […]
Hello all, i hava a problem with the Oedometer curves after the automatic calibration with ExCalibre. I took the Dobrany sand dataset for an automatic calibration and then i copied […]
Dear Prof. David Mašín I am posting the queries I have emailed you as per your advice to post it here. During calibration for the basic hypoplasticity parameters using the […]
Hi, I wanted to ask if the variables/parameters defined in the online Hypoplastic model manual for PLAXIS (https://web.natur.cuni.cz/uhigug/masin/plaxumat/node6.html) are the same for the ABAQUS UMAT?
Prof. David Masin, I am posting the queries I have emailed you earlier which you have answered and therefore I am posting it here as per your request. I wish […]
Book “Modelling of soil behaviour on hypoplasticity” has been published
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Hardcopies of my new book “Modelling of Soil Behaviour with Hypoplasticity – Another Approach to Soil Constitutive Modelling” just arrived. The book is available for hardcover or pdf orders at https://www.springer.com/us/book/9783030039752
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Recent posts
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Abaqus RITSS with hypoplastic 9.4.2025
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Fellin UMAT subroutine 2.4.2025
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Hypoplasticity clay for triaxial compression in abaqus 26.3.2025
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Abaqus RITSS methon for LDFE analysis with hypoplastic 17.3.2025
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Request for VUMAT Implementation of Mohr-Coulomb, Drucker-Prager, or Drucker-Prager Cap 28.2.2025
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Suggestions for an Advanced Constitutive Model in FEM-Based Dynamic Slope Stability Analysis 12.2.2025
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Hardening Soil or Hardening Soil-Small umat in Abaqus 2.1.2025
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hypoplastic interface 11.12.2024
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Triaxial Test Driver SANISAND 30.10.2024
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REQUEST FOR EXPRESSIONS OF INTEREST (REOI) FOR PROJECT IN CONSTITUTIVE MODELLING 23.10.2024
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Programme of the ALERT Olek Zienkiewicz school on Constitutive Modelling of Geomaterials, February 3 to 7, 2025, Prague, Czech Republic 11.10.2024
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Connecting remote sensors to the Plaxis FEM 3D using python 26.7.2024
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