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How to build a viscoelasticity damping model of solid

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I am studying the attenuation of ultrasonic wave in viscoelastic solid (using transient study). However, when adding a viscous damping subnode, I don't know how to get the viscosity parameter: bulk viscosity ηb and shear viscosity ηv. And loss factor damping can't be used in transient study.

Although I have found some formulas to calculate the value of ηb and ηv in StructuralMechanicsModuleUsersGuide (p152) :

ηb=Kη/ω

ηv=Gη/ω

K is bulk modulus, G is shear modulus, η is loss factor, ω is excitation frequecy

I can't figure out the meaning of the parameters in the formulas above. What's more, the attenuation coefficient calculated using these formulas in COMSOL was quite different from the experimental result. So I don't know how to proceed with the calculation.

I hope somebody could provide me with some advice. I want to know how to get the parameters of the viscosity or some formulas to calculate the parameters. I also hope to know some other methods or models to simulate the propagation of ultrasonic wave in viscoelastic solid material.

Thanks for your help.

Xiangwei Geng


0 Replies Last Post 29.10.2019, 10:09 GMT-4
COMSOL Moderator

Hello Xiangwei Geng

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