Excessive Deformation! 2

[muralikr1994]

Friends,
I am doing a simulation in which a cylindrical rod is being eccentrically dropped into a cylindrical hole with varying diameters.
I have defined both the bodies as deformable bodies and also have defined contact wherever necessary. I am getting an error for "15 excessive deformed elements". I have tried the various methodologies described in the forum (including ALE meshing and Remeshing rule definition, both of which aren't working)

I would be extremely grateful to receive an opinion from another person regarding this error.

I am also attaching the CAE file for reference and hope that someone can help me out.
Regards,
Murali

 

[corus]

You would do better to mesh in brick type elements rather than tetrahedral elements. You also need a much finer mesh than you have shown. One element through the thickness won't be adequate at all.

 

[muralikr1994]

I tried to finely mesh the "hex-can" part so that there would be more than one element through the thickness.
No other mesh element is compatible with the "hex-can" part, and hence I could only use tetrahedral elements. I have, therefore tried to modify certain properties of the tetrahedral elements used for meshing (have turned on "Mesh Deletion" and similar properties)

By doing both, I have been able to reduce the "excessive deformation" to only one element. The following is the error being shown after the Job is aborted.

********
Error in job 1: The elements contained in element set ErrElemExcessDistortion-Step1 have distorted excessively.
Error in job 1: There is only one excessively distorted element
Error in job 1: The ratio of deformation speed to wave speed exceeds 1.0000 in at least one element. This usually indicates an error with the model definition. Additional diagnostic information may be found in the message file.
Error in job 1: The elements contained in element set ErrElemExcessDistortion-Step1 have distorted excessively.

********

Any help regarding the error is highly appreciated.

Thanks,
Murali

 

[rounakmehta]

Hey,

I am not very experienced with abaqus so I might not be able to exactly point out your error but I got the same error myself. I kept tuning the mesh and went from a several hundred to 1 excessively distorted element. I too learnt about the ALE and adaptive remeshing but found that it would not help in my case. I guess you should try one of the following:

1) Check your Boundary conditions, especially those applying to the surfaces in contact.
2) Try increasing the step time. Whenever I get the Error " The ratio of deformation speed to wave speed exceeds 1.0000 in at least one element. " its usually a problem with the simulation being to fast. If that happens then the next increment takes place before the stress wave can propagate. A rule of thumb is that if your cylinder is moving 'd' units in time 't' then d/t should be less than 5000 m/s (I guess) as that is the speed of wave propagation in metals.

 

[corus]

You need to partition both parts so that they have a structured mesh. In that way you can use hex elements for both parts. You also need to refine the mesh of the rod so that it's a similar density to the can. You should have better luck then.