Search
Close this search box.
Notifications
Clear all

Characterizing foam viscoelasticity and simulating with ANSYS

4 Posts
3 Users
0 Likes
715 Views
Posts: 10
Topic starter
(@furocious)
Active Member
Joined: 12 years ago

Hi,

I intend to simulate the mechanical and viscoelastic behavior of a polyurethane foam which would be subject to impact and vibrational loads. I would like to know what tests I would need to perform in order to obtain the requisite information for creating a viscoelastic material model in ANSYS? Do I need to perform tri-axial compression tests or simple uni-axial compression tests should be sufficient? Is a DMTA analysis really required? I am just about to start my research, so am just clearing some confusions.

Hope to get a response soon. Many thanks in advance 🙂

Farhan

3 Replies
Posts: 3998
(@jorgen)
Member
Joined: 4 years ago

Hello Farhan,

For foams it is necessary to perform both uniaxial and volumetric tests. If your application is purely compressive, then you dont need to run tensile tests. If you expect both tensile and compressive strains, then you should perform both uniaxial tension and uniaxial compression tests.

I usually use confined compression experiments instead of volumetric compression experiements.
DMTA can be useful if you are interested in different temperatures.

-Jorgen

3 Replies
Posts: 10
Topic starter
(@furocious)
Active Member
Joined: 12 years ago

Hi Jorgen,

Many thanks for your reply. Yes my application would be purely compressive (impact), but I am still a bit skeptical about tri-axial compression testing. Wouldnt uni-axial compression suffice, since that would be the kind of impact scenario?

The confusion I am having with respect to the input required for ANSYS is that is software requires Shear Modulus - Time data. Excuse my ignorance, but can you please guide how I can obtain this information from ordinary compression test and DMTA experiments? I understand that the compression test would give me time-independent results, and that the DMTA will provide the storage and loss moduli required for Prony series input. How can I populate the Shear Modulus vs. Time table in the ANSYS Viscoelastic material model?

Thanks,
Farhan

Reply
Posts: 5
(@JoanHolmes)
Active Member
Joined: 11 years ago

I applied Prony Series and did a transient structural analysis in ANSYS but I didnt find any phase lag between stress and strain which should come because of the energy dissipated by viscoelastic material. Does it mean that Prony series alone doesnot capture the energy dissipation and we have to input a complex youngs modulus in ANSYS. Help !!!

Reply
Share: