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G.17.3.3.1 Composite Damping

Composite modal damping is based on a weighted average of strain energies in each material, (or element), for each mode (eigenvector).

The critical composite damping term DJ for mode J is computed by:

D i = Σ i = 1 n { ϕ i } T b i ⋅ [ k ] ⋅ { ϕ i } { ϕ j } T ⋅ [ K ] ⋅ { ϕ j }
where
n
=
total number of degrees of freedom
bi
=
equivalent percent of critical damping associated with component i
{φJ}
=
mode shape vector for mode J
[k]i
=
stiffness associated with component i
[K]
=
stiffness matrix for the system
Parent topic: G.17.3.3 Damping Modeling
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