Helicopter rotor blade stress calculations

[Aero_Marty]

Heyhey,

I am currently doing my final year masters project which involves testing rotor blades. I am performing a stress analysis of the blades. I will be using FEA software, but I also need to do some hand calculations. I have been looking for formulas for a while now, but I am unsure which to use and how exactly I should model it.

I was thinking I could model it as a simple cantilever, but obviously this wouldn't account for the rotation. Could anyone please help me? It would be much appreciated.

Regards


Marty

 

[FredGarvin]

If you make the assumption that you are staying in the linear realm, you can use superposition.

EDIT: WOO HOO! Number 5000!

 

[Brian_C]

Chapter 9 of Johnson's book "Helicopter Theory" covers the dynamics of rotor blades and the dynamic loads that exist in a rotor blade. Stress calculations get more complicated if you're using a laminated composite, in which case you may need to read up on lamination theory.

 

[Aero_Marty]

Thanks for your help, I'll have a look into that

 

[alphy]

Dear Marty,

It is great to hear that you are working on a project involving helicopter rotor blades. This is a complex and important area of study, and your work will contribute to the advancement of this technology.

In terms of stress analysis, I would recommend using both FEA software and hand calculations to validate your results. FEA software can provide accurate and detailed stress distributions, while hand calculations can serve as a quick and simple method for initial estimations.

When it comes to modeling the rotor blades, it is important to consider the rotation and the resulting centrifugal forces. A simple cantilever model may not accurately capture these effects. I would suggest looking into beam or shell elements in your FEA software, as they can better represent the bending and twisting behavior of the rotor blades.

As for hand calculations, there are a few different formulas you can use depending on the specific loading and boundary conditions of your rotor blades. Some commonly used formulas include the Euler-Bernoulli beam theory, Timoshenko beam theory, and the Navier's solution for a rotating cantilever. I would recommend consulting with your project advisor or a structural engineering expert to determine the most appropriate formula for your specific case.

Best of luck with your project and I hope this helps. Keep up the great work!

Sincerely,