# Query about Rayleigh Damping Parameters in FLAC3D **URL:** \ **Category:** FLAC3D\ **Tags:** fish\ **Created:** [December 2, 2025, 9:00pm UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299 "2025-12-02T21:00:04Z")\ **Posts on this page:** 6\ **Page:** 1
**Author:** ![MiguelN](https://avatars.discourse-cdn.com/v4/letter/m/6f9a4e/32.png) [@MiguelN](https://forum.itascainternational.com/u/MiguelN)\ **Post date:** [December 2, 2025, 9:00pm UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/1 "2025-12-02T21:00:04Z")
How can I query FLAC3D, version 7 or 9, to obtain the Rayleigh damping parameters (specially about alpha & beta), either through FISH or from the command line? Thanks in advance ---
**Author:** ![MiguelN](https://avatars.discourse-cdn.com/v4/letter/m/6f9a4e/32.png) [@MiguelN](https://forum.itascainternational.com/u/MiguelN)\ **Post date:** [December 4, 2025, 1:49pm UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/2 "2025-12-04T13:49:41Z")
After searching and searching, I finally found the _zone gridpoint list dynamic_ command, which gives me the values. It definitely wasn’t easy to find. GEOBOT didn’t provide it ☹ Anyway, I knew there was something like that, but I couldn’t remember it at all. ---
**Author:** ![Ankitkumarsuman1](https://avatars.discourse-cdn.com/v4/letter/a/8491ac/32.png) [@Ankitkumarsuman1](https://forum.itascainternational.com/u/Ankitkumarsuman1)\ **Post date:** [January 15, 2026, 12:42pm UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/3 "2026-01-15T12:42:54Z")
Hi MigueIN, I have some doubts about the reduced timestep. While running, the timestep is around 10^-9, which is very small, and the computational time is very high. Can you help me please with this? ---
**Author:** ![MiguelN](https://avatars.discourse-cdn.com/v4/letter/m/6f9a4e/32.png) [@MiguelN](https://forum.itascainternational.com/u/MiguelN)\ **Post date:** [January 19, 2026, 11:46am UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/4 "2026-01-19T11:46:07Z")
Hi @Ankitkumarsuman1 **Good morning. Your timestep is becoming very small. To improve this, you have several options:** • Try to check whether you have very stiff elements with small sizes. This can work against the timestep. Try increasing your zone sizes. Likewise, elements with high stiffness also significantly reduce the timestep. • Have you tried using a different type of damping? Hysteretic damping can help a lot, in addition to reproducing a more realistic ground behavior. There is another damping option that was added in the latest version of FLAC3D. It performs better than Rayleigh damping. Look into how to use it, as it does not penalize the timestep. ---
**Author:** ![Ankitkumarsuman1](https://avatars.discourse-cdn.com/v4/letter/a/8491ac/32.png) [@Ankitkumarsuman1](https://forum.itascainternational.com/u/Ankitkumarsuman1)\ **Post date:** [January 22, 2026, 4:16am UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/5 "2026-01-22T04:16:32Z")
Thank you so much @MiguelN. It was the stiff interface elements which were creating problem. But now the problem is that the properties of the interface is compromised. Because the size of the elements in my model can not be further increased as I am modelling a raft and its thickness is discritised into two elements only. And i am calculating the ks and kn for the interface elements based on max((K+4G/3)/del(x)), which is giving a very high value in 10^12. ---
**Author:** ![Ankitkumarsuman1](https://avatars.discourse-cdn.com/v4/letter/a/8491ac/32.png) [@Ankitkumarsuman1](https://forum.itascainternational.com/u/Ankitkumarsuman1)\ **Post date:** [January 22, 2026, 4:21am UTC](https://forum.itascainternational.com/t/query-about-rayleigh-damping-parameters-in-flac3d/2299/6 "2026-01-22T04:21:53Z")
Also, I am using FLAC 3D version 7.0. So, the Maxwell damping is not working for the zones in this version.