Distorced elements

[Tordus]

Hi to all of you.My question is simples and quick. Is there any way (an apdl command or something) to make ANSYS solver ignore this:

*** ERROR *** CP = 5982.701 TIME= 00:17:31
One or more elements have become highly distorted. Excessive
distortion of elements is usually a symptom indicating the need for
corrective action elsewhere. Try incrementing the load more slowly
(increase the number of substeps or decrease the time step size). You
may need to improve your mesh to obtain elements with better aspect
ratios. Also consider the behavior of materials, contact pairs,
and/or constraint equations. If this message appears in the first
iteration of first substep, be sure to perform element shape checking.

*** WARNING *** CP = 5982.701 TIME= 00:17:31
The unconverged solution (identified as time 1 substep 999999) is
output for analysis debug purposes. Results should not be used for
any other purpose.

I Mean, i dont want ansys stop here, I want ANSYS ignore this, or just keep solving the non linear ANALYSIS.

I already tried the CUTCONTROL command, "SHPP,OFF" , but it seems nothing works.

Properties:
Element45
Matprops, MISO

 

[bxtsafe]

Hey Tordus. Check if all the material properties values are ok; if one material property is too low compared to others (because of a typo, for example) some nodes probably will have a large displacement, therefore some elements can be very distorted.

Another cause can be the low values of real properties as thickness and pipe diameter (also both because of typo).

good luck!

 

[Tordus]

Thank you for the answer.

Is there anyway to find out what elements cause this? Or a way to make the solver ignore this warnings/errors?

I already tried the NLDIAG command during solver and NLDPOST in POSTProcessor, but for some reason, i am not able to check the distorced elements during the solver.

The solver runs fine with NLGEOM,OFF and without substeps, the problem is when NLGEOM is on. I already tried to use a lots of steps too, but doesnt work either.

 

[rb1957]

does your front-end allow you to analyze elements for distorsion ?

does ANSYS report on element topology (like NASTRAN does) ?

 

[bxtsafe]

Tordus,

You said an important information: the solver is running when NLGEOM=OFF. That means that all material properties and real constants (ex: thickness elements) are OK.

When you set NLGEOM=ON it means that ANSYS will consider the geometry nonlinearities. So, I think the problem is that your analysis has a convergence issue.
Try to increase the number of substeps and/or change other parameters related to the TIME STEP SIZE.
Setting Automatic time stepping=on is usually a good thing.
Moreover, set "Frequency = Write every substep" and see when the analysis stoped; an analysis of last converged substep can give you good tips.
Lasty, it's important to remember that material nonlinearity and mainly status nonlinearity (i.e. contact) can cause annoying nonconvergence problems.

good luck.