Use the Damping subnode to add Rayleigh damping to the material model. The only option for the
Damping type is
Rayleigh damping.
In this damping model, the damping parameter ξ is expressed in terms of the mass
m and the stiffness
k as
Select Input parameters —
Alpha and beta — to enter the damping parameters explicitly, or
Damping ratios to derive the damping parameters from the damping ratio at two frequencies.
When Damping ratios is selected, enter two frequencies,
f1 and
f2, and the corresponding damping ratios
ζ1 and
ζ2 at these frequencies. The Rayleigh damping parameters are computed as
When the Damping subnode is added filtering is automatically enabled on the selected domains. To display the section, click the
Show More Options button (
) and select
Advanced Physics Options in the
Show More Options dialog box. The filtering is added in order to stabilize the underlying equations. This is necessary because damping is added as a right-hand-side contribution to the governing equations in the dG-FEM formulation. In general, the values for the damping parameters should represent physical behavior. If unrealistically large values are entered, the method becomes unstable even with the filtering turned on. Note that if only very small amounts of damning are added, the filter will contribute with an additional small amount of numerical damping.