# Mode shapes of the blade used in ElastoDyn **URL:** \ **Category:** Structural Analysis\ **Created:** [March 28, 2026, 6:56pm UTC](https://forums.nlr.gov/t/mode-shapes-of-the-blade-used-in-elastodyn/9654 "2026-03-28T18:56:06Z")\ **Posts on this page:** 1\ **Showing post:** 2
**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:** [March 29, 2026, 1:25pm UTC](https://forums.nlr.gov/t/mode-shapes-of-the-blade-used-in-elastodyn/9654/2 "2026-03-29T13:25:16Z")
Dear @Riad.Elhamoud, I agree that the blade mode shapes would depend on rotor speed, blade pitch, etc., and the fact that they don’t change in ElastoDyn is a key limitation of modal-based methods. However, I have not noticed this itself to be a big source of error. This topic has been discussed in other forum posts, e.g., see: > [@The consideration of interactive effect between blade and tower/rotor when the BModes mode shapes are entered to FAST.](https://forums.nlr.gov/t/the-consideration-of-interactive-effect-between-blade-and-tower-rotor-when-the-bmodes-mode-shapes-are-entered-to-fast/1507): > > Dear Dr. Jason. FAST gets the mode shapes of the blade from the BModes program, and the mode shapes are entered into the FAST simulation. However, the interactive effect between tower/rotor and blade is not considered in the mode shapes obtained from BModes. Thus, natural frequencies and mode shapes of the blade obtained from FAST time domain simulation show sort of differences from the BModes results when all DOFs were turned on in FAST simulation. When all DOFs except for the blade mode are t… > [@BModes: Blade modes for different pitch angles](https://forums.nlr.gov/t/bmodes-blade-modes-for-different-pitch-angles/1635): > > Dear Jason, In BModes and FAST the modes of a blade are defined as flapwise and edgewise modes. So I think the modes are independent from the pitch angle. In this case I’m a bit confused about the input value for the pitch angle in BModes. For the most wind turbines it is not required and can be the pitch angle of the rated conditions or are the mode shapes of BModes depend on the pitch angle? Thank you very much. Best regards, René > [@Modelling in PreComp & BModes the 5MW NREL blade](https://forums.nlr.gov/t/modelling-in-precomp-bmodes-the-5mw-nrel-blade/912): > > Hi everyone, I’m trying to model the 5MW NREL baseline WT blades in PreComp, the problem is that I can not find the lay-out materials properties nor the webs configuration. I’ve tried to contact Sandia Lab as this thread says ([Structural design of the wind turbine blade - #7 by Brian.Resor](http://forums.nlr.gov/t/structural-design-of-the-wind-turbine-blade/271/7)) but I had no answer. I need to model the wind turbine because I need the coupled structural properties of the blade (I don’t know if I’m using the right words here but I’m refering to the terms that are not… Rather from my experience, the bigger limitation in ElastoDyn is the lack of offsets in the mass and stiffness from the pitch axis and the lack of a torsional degree of freedom. Best regards, --- _[View the full topic](https://forums.nlr.gov/t/mode-shapes-of-the-blade-used-in-elastodyn/9654)._