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 that looks similar to the traditional Roscoe Surface. Have I done something wrong or this is what is expected from your hypoplastic model?
Thank you,
Hashmi
Undrained Tests with Basic Clay Hypoplasticity
Related Articles
-
Question on implementation of sand hypoplastic model with Abaqus umat
Kunpeng Wang||Constitutive Modelling|4 |
Views 2,632
Dear all, I am a PhD student in China University of geosciences. Recently, I have been working on the simulation of a pile-soil interaction with Abaqus. I simulate the sand […] -
Hypoplastcity sand model
Pooja Patil||Constitutive Modelling|11 |
Views 2,794
Not able to run the subroutine ……..error is coming ……UMAT: illegal (negative) actual void ratio detected Can anybody help -
Modelling Rate-dependent behaviour of clay [Urgent]
Balaji Bandaru||Constitutive Modelling|0 |
Views 2,236
Using PLAXIS, how to model rate dependent behavior of clay. This is to show the viscous behavior of the soil. Thank you in advance -
SSE and SPD Mohr Coulomb Crieria
Matías Sáez de Tejada||Constitutive Modelling|0 |
Views 2,877
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? -
Clay Hypoplastic Model ABAQUS UMAT
Hashmi Sohawon||Constitutive Modelling|3 |
Views 2,691
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? -
UMAT Code for Modified Cam Clay model
Mehtab Alam||Constitutive Modelling|2 |
Views 3,166
I am trying to develop UMAT code for MCC, but facing difficulty. Is there any such files available which can help me to speed up. please refer. Thank you. -
Cyclic Behavior of Sand
MOHD SAQIB||Constitutive Modelling|3 |
Views 2,221
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. […] -
Hypoplastic Interface Model: Virtual Shear Zone Thickness and Surface Rougness Coefficient
Tunç Gökdemir||Constitutive Modelling|9 |
Views 2,565
Hello, I want to use Hypoplastic Interface (Fric Subroutine) in my ABAQUS contact models. However, I don’t know how I can determine Virtual Shear Zone Thickness. It is the Parameter […]
Search SoilModels Website
Recent posts
-
Zbraslav sand – Cyclic tests by Charles University 17.1.2023
-
New features in Excalibre 17.1.2023
-
Sanisand 13.1.2023
-
SaniSand Model in Plaxis 3D 9.12.2022
-
The GA-cal software for the automatic calibration of soil constitutive laws 2.12.2022
-
Abaqus OneAPI Compiler 10.11.2022
-
Few more Question on calculating lateral displacement of pile using hypoplastic clay model 3.10.2022
-
A question about the hypoplastic model in clay 22.9.2022
-
A High-Cycle Accumulation Model for Sand (Niemunis et al., 2005) 6.9.2022
-
Malaysian kaolin – Cyclic tests by Charles University 5.9.2022
-
Problem in calculating Lateral displacement of the pile using Hypoplastic clay model 2.9.2022
-
GTS NX 25.7.2022
Recent Comments
- Shruthija Sreeram on UMAT Implementation in Abaqus (Hypoplastic clay Subroutines)
- Paul Le Roux on Zbraslav sand – Cyclic tests by Charles University
- Amrane Moussa on Download package of a complete dataset “Zbraslav sand – Cyclic tests by Charles University”
- Francisco Mendez on The GA-cal software for the automatic calibration of soil constitutive laws
- Abolfazl Najafi on The GA-cal software for the automatic calibration of soil constitutive laws
- Arie Koot on SaniSand Model in Plaxis 3D
- Sajjad Shakeri on UDSM PLAXIS
- Anis Kheffache on Abaqus OneAPI Compiler
- Kassem Dib on How can I solve the error in Abaqus mentioned below?
- Dimitrios Konstantinidis on Issues in getting the negative values of q (mean deviatoric stress) while simulating cyclic triaxial test in ABAQUS using SANISAND subroutine.
- Tomáš Kadlíček on Download Package of Charles University Implementation of High Cycle Accumulation Model
- Safia EDAOUDI on Simulating Oedometer test in PLAXIS
- Safia EDAOUDI on Simulating the oedometric test with Abaqus
- MOHD SAQIB on Issues in getting the negative values of q (mean deviatoric stress) while simulating cyclic triaxial test in ABAQUS using SANISAND subroutine.
- Dimitrios Konstantinidis on Issues in getting the negative values of q (mean deviatoric stress) while simulating cyclic triaxial test in ABAQUS using SANISAND subroutine.
- Guilherme Castro on Download Package of Charles University Implementation of High Cycle Accumulation Model
- Giada Orlando on Download Package for Hypoplastic interface model and UMAT – FRIC interface
- Paul Le Roux on PM4Sand and PM4Silt models available
Dear Hashmi, this is correct response of the model. Actually, the observed shape of stress path is due to response envelopes being translated elipses in the stress space. The normally consolidated sample response can be corrected by either using intergranular strain concept, or by so-called D-dependent L approach. It is discussed thoroughly in this reference: Mašín, D. and Herle, I. (2007). Improvement of a hypoplastic model to predict clay behaviour under undrained conditions. Acta Geotechnica 2, No. 4, 261-268. Regards David
ok, thank you David.
Can you please provide a clarification on the following:
In triax program, the following are the inputs when using hypo_clay with istrain:
fi cr, lambda, kappa, N, r, R, mr, mt, betar, chi, e0
however, when referring to your notes, it says that for hypo_clay mR is replaced by Ag and ng while mT is supplemented by mrat instead. Therefore, how can i make triax recognise these input parameters: Ag, ng and mrat?
Correct, this is because hypo_clay is 2005 version of clay model. To use the most recent clay version, use hypo_clay_anisot and set anisotropy factor alpha_G = 1. Regards David
ok thank you. is there an updated pdf manual that includes the newer versions of hypo_clay models in triax that came after 2005?
I am currently using hypoplasti_clay_anisot_istrain, can you please confirm that the parameter nu is poisson’s ratio?
Hi David,
Can you please clarify the following parameters in Triax:
hypoplasti_clay_anisot_istrain: fi cr, lambda, kappa, N, nu, alpha, R, betar, chi, G0, n, mtrat, inic. his. var.: e0, istrain, pt
1. what is G0? confused that it could mean Ag or is it just initial shear stiffness?
2. is the n the same as ng?
3. what to insert for istrain and pt after e0? (i initially left them blank)
Thanks!
Hi Hashmi, G0=Ag, n=ng,
for istrain you should put all 9 components of complete intergranular strain tensor (row-by-row) with x being vertical coordinate, that is [isxx, isxy, isxz, isyx, isyy…]. For initial state, you probably want to set nine zeros.
for element test simulations, you will probably use pt=0, as you will not need to cope with near-zero stress problems occuring often in FE simulations. pt is arbitrary (you can leave it blank), but at least nine zeros for istrain (or your values if you know what you are doing) are important.