Dear Manish,

I think what you are looking for is directly the loss modulus. Isn't it? In the complex modulus approach, the storage modulus is the real part of the dynamic elastic modulus, the one accounting for the instantaneous elastic deformation, in phase with the applied strain, while the loss modulus is the imaginary part, that is, the part accounting for the viscous behavior, with 90º phase lag with respect to the applied stress, and thus the one that is multiplying d/dt(epsilon).

Sincerely,

Jose

I am also looking for the same viscoelastic coefficient for the metal alloy Ti-6Al-4V. The explanation given by you ( Jose Ignacio Rojas Gregorio) is very useful.

But in this model,

sigma = E*(epsilon)+eta*(d/dt(epsilon))

we can observe that dimension of 'eta' must be Pa-s. Thus, In this case we can not replace it by loss modulus whose dimension is Pa. So, Is there any relation between 'eta' and loss modulus.

Or

Can you suggest any other way to get this viscoelastic coefficient (eta) from any experimental data available in the literature.

Thanks Jose Ignacio Rojas Gregorio for your explanation. Shashidhar reddy Rajidi pointed out what exactly I need. Here the doubt lies Is there any relation or way to get eta of a viscoelastic material based on Kelvin-Voigt Model.

Yes, I thought the same when writing to you: the units are not coherent. After having a look at the model, etha is the loss modulus divided by omega (the dynamic loading frequency)

Thank you Jose Ignacio Rojas Gregorio . I have an another small doubt here. This omega, Is it a frequency of excitation or a frequency of vibration?

Because in the case of nonlinear vibrations, the frequency of vibration may not be always equal to frequency of excitation. The frequency of vibration can be fraction of frequency of excitation (parametric resonance, quasi periodic solution, chaotic response).

I am little confused about this omega. I am attaching one article in the literature in which it is mentioned as natural frequency (The relevant sentences are highlighted in yellow color). Is it (omega as natural frequency) always true or is it true only around the natural frequency?

Dear Manish,

I think that Kelvin-Voigt model is the special case of the generalized Maxwell model for N=1 and Ek=infinity. Please see the attached file.

If there are some mistakes, please correct them asd show me.

Sincerely,

Ryuzo Horiguchi (Kao Corporation)

Dear Manish,

There was a mistake in my last pdf.Please see the revised pdf.

The loss tangent is omega*mu/E. (omega : radial frequency(rad/sec), mu : viscosity(Pa*s), E: Young's modulus (Pa))

Sincerely ,

Ryuzo Horiguchi (Kao Corporation)

Dear Manish, I invit you to read this paper https://www.google.com/url?sa=t&source=web&rct=j&url=http://onlinelibrary.wiley.com/doi/10.1002/app.44209/pdf&ved=2ahUKEwi0jqP776TeAhWlKsAKHTGrC_cQFjAAegQIABAB&usg=AOvVaw1Q4sYZOoY1ox7KDS2isrbg

Dear all,

Following the comment by Ryuzo Horiguchi, the loss tangent or tan delta, also termed internal friction or mechanical damping, is the ratio loss modulus-to-storage modulus. Please, see Eq. 1, 2, and 3 in the attached pdf, as well as the Eq. in the attached images.

Hope this is useful,

Jose