Hi,
I simulate a nano - 2D indentation process in Abaqus 6.16. The simulation is in Abaqus/Standard and non-linear is switched on.
The process is force controlled - I typ in the force and want the stress, strain and displacement. For forces until 0.08 Newton the simulation runs fine, but above that value not anymore. Those are the warnings:
1. Displacement increment for contact is too big.
2. Excessive distortion at a total of 6 integration points in solid (continuum) elements
3. The strain increment has exceeded fifty times the strain to cause first yield at 1 points
In theory the simulation has to work with forces until 1 Newton, but I would be fine with 0.2 or 0.3 Newton. Does anyone has a hint? Can I realize the simulation in Abaqus/Standard or do I have to switch to Explicit?
Furthermore, the aim of the simulation is to gain a stress- strain curve of the material (or - later on- of a coating). Therefore, I have to compair force - displacement - pairs during the simulation with the ones I obtain in experiments. In case the deviation from the experiment is too high, the increment has to repeat and the input (tangent modul) has to change. Since I have to experience in this field I am not sure if I can realize with matter in a subroutine or a python script. Does anyone have some experience in a similar case? Some literature regarding this matter would help as well.
Best regards,
Marco
Hi, Marco.
1. Try to use displacement control instead of force one.
2. Condense FE mesh in the vicinity of contact zone.
Victor.
Hi, Marco.
1. Try to use displacement control instead of force one.
2. Condense FE mesh in the vicinity of contact zone.
Victor.
Dear Marco,
Check your material model parameters are correct or not as you claim excessive displacement has taken place. did you use contact element to define the interface anything..did you define the displacement based convergence criteria..i think contact point need to define with normal and shear displacement and also check material properties are correct or not..also i recommend you to check ABAQUS manual..ABAQUS is the standard software..all the best..
Hi Marco,
I think the Errors could be solved with,
1) Displacement increment for contact is too big. - You could use more number of increments to apply force and you may adjust Stiffness of contact elements in case of Penalty contact(1D springs)..
2) Excessive distortion at a total of 6 integration points in solid (continuum) elements - (this error is generally due to negative volume of integration point (virtual hourglass energy) at center gauss point of solid element which is in most cases 1 Integration point element) In order to get rid of this Error, you could either use Reduced Integration Elements (i assume instead C3D8H -> C3D8RH) or you could use Elements with more Integration points(if its not too costly from simulation point of view).
I suggest, you should try to simulate whole process at first on 1 element model and then You could easily solve errors and later on simulate your actual model. (I assume)
I hope it helps.
Regards,
Dhruvil Patani
Thank you all for your answers! It was indeed a problem with the incrementation. I will try to adjust the stiffness value later in the project.
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