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
-
SImulation with hypoplastic model for granular materials in ABAQUS
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 […] -
3D analysis with Basic Hypo-Plastic 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 -
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 […] -
New book “Modelling of Soil Behaviour of Hypoplasticity”
I have just returned to Springer proofs of my new book “Modelling of Soil Behaviour of Hypoplasticity – Another Approach to Soil Constitutive Modelling“. It will probably still take few […] -
ALERT Geomaterials – SoilModels support declaration
ALERT Geomaterials (The Alliance of Laboratories in Europe for Education, Research and Technology) is a European organisation including 33 Universities or Organisations, which are most active in the field of numerical […] -
SANISAND pile-soil-interaction ABAQUS
Hi everyone: I am trying to use SANISAND as the constitutive model of soil, and use ABAQUS software to simulate pile-soil interaction. Is it better to choose “Static, Genaral” analysis […] -
boundary surface plasticity
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 […] -
Supporting Organisations
Recent posts
-
Two postdoctoral positions in computational mechanics in Ben Gurion university and Ariel university, Israel, are available immediately 28.2.2021
-
K0 determination Reloading using HP clay model 22.2.2021
-
Seismic Liquifaction 11.2.2021
-
Modelling cyclic loads in Tochnog 11.2.2021
-
Soft soil model vs Soft soil creep model 8.2.2021
-
Boundary value problems for granular materials subjected to earthquake loading 8.2.2021
-
Guidance for a newbie 6.2.2021
-
Modelling Rate-dependent behaviour of clay [Urgent] 1.2.2021
-
Postdoctoral Fellowship in computational geomechanics 27.1.2021
-
USDM – Creep -SCLAY1S 25.1.2021
-
Hardening Soil Model in Abaqus 25.1.2021
-
Effects of water content in sand in hypoplastic strength parameters 25.1.2021
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