One or more elements have become highly distorted.~~~ error message.

[ryan799]

Hello, everyone!

I'm performing thermal-structure transient analysis using ansys.After thermal analysis, the structure analysis is performed. The error was occured during analyzing.The error message was follows.

" One or more elements have become highly distorted.~~~~.Try incrementing the load more slowly(increse the number of substeps or decrease the time step size). You may need to improve your mesh to obtain elements with better aspect ratios. ~~~. "

I increased the number of substeps and decrease the time step size. However, the error was occured again at the same time(2.1e-7s). I think there is a problem in the meshes. Therefore, I want to know what I have to do for solving this problem. Please give me some tips. The follows is my meshed model. The top part was meshed 1 micrometer squares.

 

[ryan799]

The high pressure is applied at the top of the tip. The period was 2.0e-6 s.

 

[Transient1]

What type of elements are you using?

What is it that you are modeling (material/constraints)?

What strains/stresses are you seeing (i.e. do they make sense)? Double check your material properties.

It is likely a problem with the mesh. Triangular elements do not perform well when the stress gradients are very high. Try eliminating those elements.

 

[omidomidi]

check displacements in different substeps.you may need to kill elements which are highly distorted.

 

[ryan799]

Thank you for your advices,Transient1 and Omidomidi.

I'm going to do as you said.

 

[jeffly]

Hello:
I have the same error message as Ryan799 does. Can anyone give me advices on how to deal with this? I ran (2D) simulations on pinching silicone rubber tubing using hyperelastic material model. Stress vs. strain data sets from simple tension, planar tension (for pure shear), and biaxial tension tests were input into ANSYS. I always got the severely distorted element error when the tubing was about to be folded into halves as it was pinched down along its tubing diameter direction.

Thanks so much.

Jeff

 

[TERIO]

Jeff,

I am not sure specifically about ANSYS but some FE codes allow you to:

1. Stop the analysis sometime before the mesh gets bad.
2. Generate a new mesh on the deformed shape.
3. Map the results from the old mesh to the new mesh.
4. Proceed with the analysis.

You may want to look into something like this if you need results past the point where your simulation crashes.

 

[jeffly]

Thanks, TERIO.
I'll find out if ANSYS WB even allow that option. It's an excellent suggestion.

Jeff.