4DOF and damping, R

[GregHolmberg]

The 4DOF model requires values for the damping, R, of the air, top, sides, and back. How can I measure these values?

I know how R is related to Q or δ. R = √(Km)/Q = δ√(Km)/π

In section 4.3.3 we see how to measure Q or δ of a rectangular panel. For various species commonly used for top panels, we get a range of Q from about 100 to 200.

But what we need for the 4DOF model is the Q of the completed (braced) top. On page 4-28, it says typical Q for a top is about 30. Indeed, using the numbers in Table 2.4-1, Q=28.6.

But how can I measure the Q or δ of a completed top? Can I use the peak-to-peak formula in Equ. 4.3-5?

And what about the "sides", which are really the combined areas of the top and back outside the Chladni lines?

For air, I guess I can stick with the R=0.005 Ns/m value from the book.

Greg