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FRF with different rubber thickness

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Posts: 14
 gh
Topic starter
(@gh)
Active Member
Joined: 16 years ago

hi all,

The question is about my sandwich beam two steel and a viscoelastic material with 50ib mass at the tip.

When I made many run with different rubber thickness, I saw two different cases

1-The Hrubber=<Hsteel

2-The Hrubber=>Hsteel

Why the decrease in rubber thickness in Case 1 is increases the damping and in Case 2 decreases the damping. The decrease in rubber thickness should always give me increase in damping.

Any help is appreciate it.

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

Are you talking about experimental data or finite element simulations?

If you are using FE simulations. What material models did you use to represent the response of the steel and the rubber?

-Jorgen

5 Replies
Posts: 14
 gh
Topic starter
(@gh)
Active Member
Joined: 16 years ago

thank you Dr.Jorgen

im using ABAQUS simulations and im using hyperelastic Mooney Rivlin +viscoelastic prony series model for my viscoelastic material.what about the steel?im only using E & density for steel.

for element type,im using C8D20 for steel, and C8D20H for my viscoelastic?

Do you think there is something wrong in these material models or element types.

thank you so much for your help.

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

Your simulation sounds good. My only concern is the Mooney-Rivlin + Linear viscoelasticity model. That model will only be less accurate at large strain. Perhaps that is causing the results that you did not expect...

- Jorgen

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Posts: 14
 gh
Topic starter
(@gh)
Active Member
Joined: 16 years ago

what do suggest Dr.Jorgen for this problem.Im only looking for the result between 1-40 HZ.Is changing the Mooney-Rivlin will solve the problem.What is the best model for my case.Thank you again.

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

Accuracy concern is more dependent on the strain amplitude than the frequency. What strain amplitudes are you interested in?

- Jorgen

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