possible solutions to the error of negative Jacobian

[aolei yang]

Hello!

Lately, I've come across an issue, the "error: detecting negative Jacobian." Despite my numerous attempts, which involved adjusting solver parameters and refining mesh quality for each component, I haven't gotten any positive results. I've also searched through previous forum posts with similar problems, but the suggestions provided didn't offer much assistance. Are there any other possible methods I may try to troubleshoot this issue?

Thank you very much for your help!

[maas]

Hi aolei yang

Since there are many potential causes for negative jacobians, I would be helpful if you could share your model. You may upload it here as an attachment if it's not too big, or you can use a filesharing service.

Thanks,

Steve

[aolei yang]

Dear Steve,

Thank you very much for your reply and help!

Since there is a policy about the research data in our lab, would it be possible if I email the file to you?

Best regards,
Aolei

[aolei yang]

About possible solutions to the error of negative Jacobian.

Sorry to bother you for the troubleshooting issue. I am wonering if this is possible that I send the file with negative jacobian to you for help!

Best,
aolei

[maas]

Hi Aloei,

Yes, please feel free to email me at steve dot maas at utah dot edu.

Best,

Steve

[aolei yang]

Dear Steve,

Thank you very much for your kind help!

Best regards,
Aolei

[aolei yang]

Dear Steve,

I have sent the email with the attached model file to you.

We are looking forward to your reply if the email was correctly delievered!

Thank you very much for your kind help!

Best regards,
Aolei

[odeibo]

Hi,

I am also facing negative jacobian problem in a knee model simulation. When I run the simulation in the debug mode, I see how the meniscus deforms completely. I have changed parameters but I still have the same issue. What could be the reason?

Thank you very much for your help!

Kind regards

[odeibo]

I have upload two more .gif files where the problem can be observed.

[maas]

Hi odeibo,

The quality of the images is rather poor and I can't really see what is going on. Perhaps try sharing the febio model instead (the .fs2 or .feb file). If I can reproduce the problem on my end, I might be able to offer some guidance.

Best,

Steve

[odeibo]

Hi,

I have sent the email with the attached model file to you.

Thank you for your help!

[maas]

Hi,

Thanks for sending me the file. I've replied to your email with some suggestions. Hopefully they are helpful. Let me know if you have any further questions.

Best,

Steve