Rayleigh Damping Parameters
When the coefficient of proportional damping ξ is specified (in frame "Soils") for some material the program will compute the Rayleigh damping parameters α and β using one of the following two methods:
- The chosen eigenfrequency ωa is assumed to be the least damped frequency associated with the damping coefficient ξ. Then the Rayleigh parameters are calculated as:
- The least damped frequencies appear in the interval, which is bounded by frequencies ωa and ωb (ωb > ωa) both damped by damping coefficient ξ. The Rayleigh parameters then follow from:
The damping coefficient for an arbitrary eigenfrequency ω then reads:
This relationship ensures that the frequencies between ωa and ωb are damped less and the frequencies outside the interval are damped more than ωa and ωb.
Selection the approach for damping in "Analysis" frame.
Selection of frequencies for damping
Further details are available in the theoretical manual on our website.