Many SimScale users are wondering how to calculate Rayleigh coefficients (\alpha & \beta) for material damping. The answer is quite simple, please have a look at the procedure on page 4 of this publication: Approach for Selection of Rayleigh Damping Parameters Used for Time History Analysis
You have to only start with having three values in mind:
- Modal damping value (\zeta). The larger the value the greater will be the damping effect. For example, \zeta = 0.1
- Lower (ω0) and upper (ω1) natural frequency values of the structure. These values can be attained via free vibration frequency analysis, i.e. the lower and upper natural frequency range of interest. For example, ω0 = 100 Hz and ω1 = 500 Hz
Hope this helps.