# Deflection of ElastoDyn **URL:** \ **Category:** Structural Analysis\ **Created:** [April 14, 2020, 9:40am UTC](https://forums.nlr.gov/t/deflection-of-elastodyn/2233 "2020-04-14T09:40:01Z")\ **Posts on this page:** 1\ **Showing post:** 8
**Author:** ![Jason.Jonkman](https://dub1.discourse-cdn.com/nrel/user_avatar/forums.nlr.gov/jason.jonkman/32/3086_2.png) [@Jason.Jonkman](https://forums.nlr.gov/u/Jason.Jonkman)\ **Post date:** [May 18, 2020, 1:08pm UTC](https://forums.nlr.gov/t/deflection-of-elastodyn/2233/8 "2020-05-18T13:08:30Z")
Dear Dhaneesh, Buckling is not directly considered within OpenFAST. Of course, you can post-process the loads output from OpenFAST to calculate the onset of buckling. As has been discussed several times on this forum (e.g.: [Foundation Stiffness and damping in FAST v8](http://forums.nlr.gov/t/foundation-stiffness-and-damping-in-fast-v8/1059/1)), foundation flexibility and soil-structural interaction are not available in the master branch of OpenFAST. That said, NREL has been working on this recently, by both including a 6x6 stiffness matrix (coupled springs model) at joints in SubDyn and by introducing a new module, SoilDyn. SoilDyn provides an option for a simple 6x6 stiffness matrix, but also includes options for interfacing to the REDWIN DLLs developed by NGI (to model soil-structure interaction via a superelement, including soil hysteresis), as well as and a placeholder for future implementation of a p-y and t-z curves. These are not currently included in a public release, but are being developed in branches on forks of OpenFAST. Best regards, --- _[View the full topic](https://forums.nlr.gov/t/deflection-of-elastodyn/2233)._