The viscoelastic materials have a viscosity factor . Because viscoelastic materials have the viscosity factor, they have a strain rate dependent on time. Viscoelastic substance dissipates energy (heat) when a load is applied. The relevant parameter is the viscosity factor and the viscoelastic materials may depend on non-Newtonian law of viscosity unlike pure viscous material (water for example).

The interplay between the viscous and elastic properties over a period of time can give you a measure of the viscoelastic characteristics of the media. Also, note that elasticity exhibits instantaneously, but viscosity over a period of time for both Newtonian and non-Newtonian fluids. Check the ratio between E and eta over a some time period.

Thanks for answer.

In your reply, you have mentioned, ".....Also, note that elasticity exhibits instantaneously, but viscosity over a period of time for both Newtonian and non-Newtonian fluids.....". Accordingly, the viscosity exhibits over a "period of time" for both Newtonian and non-Newtonian fluids. I am interested to know the "period of time" for both "Newtonian" and "non-Newtonian" fluids, at least approximately, as observed in Laboratories and in Galaxies.

Reference materials and books may be welcomingly mentioned.

Thank you, Dr. Ahmed, for your answer.

I have a query. How do you correlate "viscosity factor" with "coefficient of viscosity"?

Could you please give a non-Newtonian law of viscosity other than that in the Maxwellean form?

References are welcome.

Regards.....

Dear P.K. Karmakar

A visco-plastic is material that behaves as a rigid body at low stresses but flows as a viscous fluid at high stress. It is named after Eugene C. Bingham who proposed its mathematical form.[1]

It is used as a common mathematical model of mud flow in drilling engineering, and in the handling of slurries. A common example is toothpaste which will not be extruded until a certain pressure is applied to the tube. It is then pushed out as a solid plug.

I would suggest to read the following reference: