Shear-Thickening Behavior

[paulinaalaman1]

Hello, 

I was wondering if there are any thermoplastics that show shear thickening behavior in the provided material library. 

[bernor_mf]

@paulinaalaman1 

Hi,
Actually, I have never heard of shear thickening thermoplastic melt.
Doubt such a material data set  is available in Moldflow material database.
Could you elaborate what you would like to accomplish?

For thermoplastic melt it is the shear thinning behavior of the polymer melt.

• Increase shear rate and the viscosity becomes lower.
• Increase temperature and the viscosity becomes lower.
• Lower shear rate and the viscosity becomes higher.
• Lower temperature and the viscosity becomes higher.

Regards,
Berndt

[paulinaalaman1]

Hi @bernor_mf ,

Yes, you are correct. From my research, it appears that shear-thickening thermoplastic melts are quite rare, and I haven't been able to locate any within the Moldflow material database either. I thought it would be beneficial for students to replicate a flow curve by performing fill simulations. Currently, most thermoplastics in Moldflow exhibit pseudoplastic (shear-thinning) behavior. I was hoping to find a shear-thickening thermoplastic so that students could obtain and plot data for both types on the same flow curve for comparison.

Best regards,

Paulina

[bernor_mf]

Hi,
thank you for the feedback and explanation.

Do you by chance have material raw data for melt shear-thickening, and more?
You could then do data fitting at lab.
How to contact the Autodesk Moldflow Plastics Lab for material data requests
Maybe send the lab an email and check if they have an udb-file that meet your request?

Another option would be to play with a material and the viscosity model Cross-WLF coefficients.
I am not sure the model work for shear-thickening, as mainly used for shear-thinning.
You could then copy a material data set from database to a personal database, personal udb, that could be shared and used by others.
How to create a personal material database in Moldflow

Maybe a way would be to compare materials with big difference in viscosity?

Regards,
Berndt