Viscous Damping Ratios

System (a)

Viscous Damping Ratio z (b)

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

Material

Viscous Damping Ratio z  (under approximately 20o C) (c)

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