| System |
Viscous Damping Ratio ζ (as percentages of critical damping) |
|---|
| Metals (in elastic range)
|
less than 0.01
|
| Continuous metal structures
|
0.02 - 0.04
|
| Metal structures with joints
|
0.03 - 0.07
|
| Aluminum / steel transmission lines
|
~ 0.04
|
| Small diameter piping systems
|
0.01 - 0.02
|
| Large diameter piping systems
|
0.02 -0.03
|
| Auto shock absorbers
|
~ 0.30
|
| Rubber
|
0.05
|
| Large buildings during earthquake
|
0.01 - 0.05
|
| Prestressed concrete structures |
0.02 -0.05
|
| Reinforced concrete structures
|
0.04 -0.07
|
The data above are taken from: Vince Adams and Abraham Askenazi, Building Better Products with Finite Element Analysis, OnWord Press, Santa Fe, NM.
| Material
|
Viscous Damping Ratio ζ (under approximately 20 ºC)
|
|---|
| Aluminum
|
~ 0.5 10-4
|
| Lead (pure)
|
~ 10-2
|
| Iron
|
1 to 3 10-4
|
| Copper (polycrystalline)
|
10-3
|
| Magnesium
|
~ 0.5 10-4
|
| Brass
|
< 0.5 10-3
|
| Nickel
|
< 0.5 10-3
|
| Silver
|
< 1.5 10-3
|
| Bismuth
|
~ 4 10-4
|
| Zinc
|
~ 1.5 10-4
|
| Tin
|
~ 10 10-4
|
The viscous damping ratios are obtained by dividing by 2 the flexural loss factors of the materials given in: L.Cremer and M. Heckl, Stucture-Borne Sound, Springer-Verlag, New York, 1988.