flexional rigidity

[doudou141083]

Hi,

I'm trying to make a Micro air vehicle with MFC(macro fiber composite). I would like to calculate the flexional rigidity of my MFC wich is D=E*h^3/(12*(1-nu^2) for a plate.

So I must have the young modulus E and the poisson's ratio "nu" but for the MFC, I have the young modulus E1 and E2 in the two directions and "nu12". How can I calculate the flexional rigidity?

Thanx,bye.

 

[wes616]

Try searching first.

thread327-198657



Wes C.
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No trees were killed in the sending of this message, but a large number of electrons were terribly inconvenienced.

 

[doudou141083]

Hi Wes,

I had seen this post and I know how to calculate the A,B and D 's matrix. I have it done for other applications with my MFC.
But I don't see how it can help me to calculate the flexional rigidity. My goal is to calculate the resonance frequency of my MFC so I need this flexional rigidity. I have a logicial to do that but the reply seems to be false and I would like to check this.

If I do what you said in the other post, I find Ex and Ey but it doesn't help me or I don't understand how...

Thanx for your reply,
Elise.

 

[RPstress]

Is your macro fiber composite similar to this stuff?

http://www.smart-material.com/media/Publications/MFC-EnergyHarvesting.pdf

 

[epom]

doudou,

If I understand well, you would like to determine the flexural modulus of your laminate. For a composite laminate there are 2 flexural moduli (Efxx and Efyy)and one torsional modulus. The Flexural moduli are evaluated using the terms d11 and d22 of the compliance matrix.

Efxx = 12/(d11 t^3)
Efyy = 12/(d22 t^3)

where t = laminate thickness

You can find the demonstration of those equations in the Introduction to composite materials S.W. Tsai

Regards,