Discussion Closed This discussion was created more than 6 months ago and has been closed. To start a new discussion with a link back to this one, click here.

Failed to find a solution. The relative error is greater than the relative tolerance.

Please login with a confirmed email address before reporting spam

Hi all,
I'm trying to simulate a Piezoelectric transformer using the piezoelectric devices physics.
My structure is quite simple:
it's a thin circular membrane of piezoelectric material thick 1um (AlN), with upper concentric electrodes for primary and secondary (inner circle is the primary while the secondary electrode sorrounds the primary electrode).
Under the AlN membrane there's silicon thick 4um
I run the eingenfrequency study step in order to find resonant frequencies, but when I run frequency domain study step, in a small range of the chosen resonance, I get the error: "Failed to find a solution. The relative error is greater than the relative tolerance".
As the problem has a cylindrical simmetry, this model is set in 2D-Axysimmetric

- I have to say that I get this error when the frequency is extremely close to the resonant frequency.
- I have inserted damping and losses for all materials, thus getting a finite quality factor (so the problem is not related to undamped response)
- I ve tried an extremely fine mesh
- I ve tried to change solver parameters (although i m not an expert in solvers) and this seems to change a little the frequency where I get the error (since the Q is around 4000, I've set a 100Hz frequency step), but at the end I always get the error.
- I ve read all forum discussions about this error, but nothing seems to help me.
- If I change the radius of the structure from about 500um to 50um, I do not get the error, furthermore the simulation is faster!

How can I resolve this error?

Thanks in advance!

Antonio

2 Replies Last Post 2015年8月8日 GMT-4 03:03
Josh Thomas Certified Consultant

Please login with a confirmed email address before reporting spam

Posted: 1 decade ago 2014年8月22日 GMT-4 11:00
Antonio,

Would you be able to post your mph file to the forum? If the file size is too large, you can Clear all meshes and Clear all solutions before posting.

--
Best regards,
Josh Thomas
AltaSim Technologies
Antonio, Would you be able to post your mph file to the forum? If the file size is too large, you can Clear all meshes and Clear all solutions before posting. -- Best regards, Josh Thomas AltaSim Technologies

Please login with a confirmed email address before reporting spam

Posted: 9 years ago 2015年8月8日 GMT-4 03:03
Hi,
I have the same problem which had confused me for a long time. Do u find a solution or know where the problem is?
Thank you for your reply.
Yuanyuan
Hi, I have the same problem which had confused me for a long time. Do u find a solution or know where the problem is? Thank you for your reply. Yuanyuan

Note that while COMSOL employees may participate in the discussion forum, COMSOL® software users who are on-subscription should submit their questions via the Support Center for a more comprehensive response from the Technical Support team.