Normal cannot be completed in 4 elements

[Hussain2339]

Dear all,

I am simulating 4-points bending on extruded panels.

I came across an error that "Normal cannot be completed in 4 elements".

Can you please advise how to fix this

?

 

[NRP99]

Check your mesh. Most probably the elements quality is not good. You can open the odb file created after you submitted the analysis to solve and check the elements and their location in the "display group" => Elements=> search for ErrEleShellNormal set. Re-mesh model with good quality mesh. Due to warped elements Abaqus is identifying the normal are not aligned with the neighbor elements

 

[FEA way]

Do you use tie constraint to connect the parts ? Adjustment enabled for these constraints often causes errors such as negative volume and could potentially also cause the problem discussed here.

 

[Hussain2339]

I am using general body contact. No Tie constraint.
That issue was resolved by adjusting mesh sizes.

Now I have got another error.

The time increment required is less than the minimum specified
Error in job Small: THE ANALYSIS HAS BEEN TERMINATED DUE TO PREVIOUS ERRORS. ALL OUTPUT REQUESTS HAVE BEEN WRITTEN FOR THE LAST CONVERGED INCREMENT.
Job Small: Abaqus/Standard aborted due to errors.
Error in job Small: Abaqus/Standard Analysis exited with an error - Please see the message file for possible error messages if the file exists.

I increased step time as well. It runs analysis up to some time and then shows an error.

 

[NRP99]

Then you need to debug model for convergence issues. Some tips are provided in thread799-492205.

 

[FEA way]

Check Simuleon’s blog article "6 Tips solving non convergence with Abaqus FEA". Usually the problem lies in contact so you could start by adding stabilization to avoid potential rigid body motions.