Greetings
i used interface Vumat with Umat for simulating CEL problem, after 50% of analysis, i got the error as “Excessive incremental rotation of the elements in element set ” i researched the meaning about this error in literature but h couldn’t find how fix it. Anybody can help me and advise.
Regards
Related Articles
-
Oedometer test simulation with “Sand Hypoplasticity Model” in Plaxis
Hi, I just came across some problems with the implementation of the “Sand Hypoplasticity Model” in Plaxis. I wanted to to perform a simulation of an oedometer test on a […] -
UMAT Code for Modified Cam Clay model
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. -
ExCalibre Automatic Calibration
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 […] -
Initial Stiffness of CU test in Masin’s 2014 Model
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 […] -
Undrained Tests with Clay Hypoplasticity Intergranular
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 […] -
Hypoplastic model for Granular soil
Hello everyone, Could you please anyone tell me that how I can define the hypoplastic constitutive model for granular soil in ABAQUS 6.13. With Regards, Naveen. -
Compile triax calibration software under windows
1. Download install exe (32 or 64 bit) from https://cygwin.com/install.html 2. Choose a mirror site / click Next and select all packages you need for compiling: Type: “gcc” into search […] -
Cyclic/monotonic direct shear test (matlab driver)
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 […]
Supporting Organisations
Recent posts
-
BCV bentonite experimental and modelling datasets 14.11.2023
-
Challenges in simulating geomechanical models using Mohr-Coulomb with Tension Cut-Off in Abaqus 20.10.2023
-
Analys soil liquefaction with Abaqus under blast load 19.10.2023
-
Hardening soil Model UMAT 13.9.2023
-
Problem with VUMAT interface 20.8.2023
-
UMAT and oneAPI compiler issues. (SOLVED…i hope :p) 5.8.2023
-
Oedometric Test Soil Test Plaxis 21.7.2023
-
Problem in simulating CPT using SANISAND04 10.7.2023
-
Problem with UMAT for clay hypoplasticity. Program exiting. 30.6.2023
-
Example of FLAC3D data file 10.6.2023
-
sigini ans sdvini subroutine example for soil model in Abaqus 6.6.2023
-
Presentations from Prague Geotechnical Days 2023 including 29th Prague Geotechical Lecture by Yannis Dafalias 25.5.2023
Hello Elfattah,
most probably your time step is too large. You can arbitrary decrease it with the “time scale factor” (maybe other name) in the “Step” module.
I recommend you should familiarize yourself with the theory of the CEL method. This might help you to solve the problem related to these error messages related to the CEL method in ABAQUS.
Best regards
Johannes
Dear Labenski
thank you for response, CEL depend on fixing the the mesh in space, so the distortion shall not be developed. i tried to reduce the time and mesh size, but the error is displayed after about 25 % instead of 50 % of analysis. Noted I used interface Vumat/Umat by Britta Bienen
Actually the mesh is not fixed as you might expect. The CEL method consists of three steps. In one step, the “fixed” mesh will be deformed according to the load and the corresponding material response. In a latter phase the deformed mesh will be resetted to its initial position, i.e. as user you think the mesh is fixed in space.
So reducing the time step with the time scaling factor (see image: https://imgur.com/a/kEHLYRy) usually worked for me to resolve this problem with CEL simulations. By standard I use a time scale factor of 0.9, but sometimes you may need even smaller factors. Of course, the computational time is increasing if you decrease this factor.
I see, i have already tried to use time scale factor to 0.5 and 0.85, but the error is displayed after about 25 % instead of 50 % of analysis. in addition, i tried too reduce the mesh size but i still receive the error. this error appear when i use Vumat. in contrast, the analysis has complete using anther constitutive law such as Mohr Coulomb or cap plasticity with the same model.
Did you receive this error before for CEL model ? and do you think that there problem in Vumat/Umat interface ?
I am using the Vumat-Umat interface for vibratory-pile installation simulations without problems. In most cases I could resolve this error with the time scale factor. You should also check if your boundary conditions are defined correct. You should only define boundary conditions you really need. Do not constrain all DOF at all boundaries, if you don’t need to.
the error element is existing at symmetry face near the contact zone
in addition, the energy balance is not normal. because the dramatically decreasing of total energy is occurred and the internal energy is very low. Noted, there is message state the the stretch element instead of gradient deformation
Hello
subscribe to and seek assistance from the
ABAQUS mailing list
https://groups.yahoo.com/neo/groups/Abaqus/info
Search the archive of the list before posting in it.
The list does not accept attachments.
Or
http://www.eng-tips.com/threadminder.cfm?pid=799
or from the ResearchGate discussion forum.
For advice on mechanics in general, including modeling,
you can consult
http://imechanica.org/
If you need subroutines: as an introduction get the file
http://imechanica.org/files/Writing User Subroutines with ABAQUS.pdf
Good luck
Frank