RE: Issue with high shear rates in exponential Phan-Thien Tanner viscoelastic model

Hello everyone,

I am facing an issue with my simulation using an exponential Phan-Thien Tanner (PTT) viscoelastic model. When I use this model, extremely high shear rates quickly develop at the corners of my melt inlet. These high shear rates then propagate towards the melt front and eventually catch up with it. As a result, the entire model experiences excessively high shear rates, leading to unrealistic and incorrect results.

I am using the viscoelastic solver and have already experimented with different meshes and solver settings, but so far, I have not been able to improve the situation.

Has anyone encountered a similar issue or has any suggestions on how to mitigate this problem? Any advice on stabilizing the shear rate behavior  would be greatly appreciated!

Thanks in advance!

Felix Asked on 20 3 月, 2025 in Moldex3D.
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3 Answers

Hi Marcus,

Thank you for your response. Unfortunately, I am a student and using an educational license, so I do not have access to a technical support representative.

However, I would still appreciate any general advice on this issue. Are there any typical causes for excessively high shear rates in PTT viscoelastic models? Could it be related to specific material parameters, boundary conditions, or solver settings?

Any guidance or troubleshooting suggestions would be very helpful!

Thanks in advance,
Felix

Answered on 24 3 月, 2025.
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