Elastodynamics demo in fenics book: Curious about damping

Question

I ran the Elasto-dynamics demo given in Ch. 26 of FEniCS book with the corrections noted in the attached related question. I ran the code with zero percent damping (eta = 0) and eta = 1.0 damping - that should be 100%, right? The output looks like this. Do these numbers make sense? I mean there is hardly any difference in the displacement caused by the input pulse at the highlighted cell or other cells. Please save the image in your computer and then view.

Comments

The displacement in "x" is (0.00197643 - 0.00168439)/0.00168439 = 0.17, i.e. 17% greater in magnitude for the second case. Similar difference is seen in other values. Why do you say that there is hardly any difference?

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I mean with respect to the value of eta. I thought eta = 1 should mean 100% damping. I thought that will cause considerable reduction compared to 20% damping (eta = 0.2). The viscoelastic equation given in fenics book is:

What am I missing here? Can damping go beyond 100%?

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I know I'm a bit late to the party on this one, but here goes:

The damping coefficient is not numerical, so it does not go from 0 to 1, it is a physical dynamic viscosity which has units of [Pa s] or [Poiseulle] if you want. So the actual value of the viscosity is a material parameter rather than a percentage, and therefore values of 0 or 1 do not correspond to 0 or 100% viscosity.

I hope this answers your question.