need help on some formulas for a university assignment
 

They should be used on a calculating the twist agle of a beam.

I already have the Torque = Distance x force

but i don't have a clue about the other two, any clues?


kT= T/(q/L)



T / J = ( G Θ )

T = applied torque
G = modulus of elasticity in shear (like E value)
J = polar moment of inertia, from standard formulae e.g. solid circular bar J = pi d^4 / 32

Elastic torsion of circular sections

T/J = t/r = G phi / L

t = torsional shear stress
phi = angle of twist

First formula, don't know what q is, but perhaps rotation is proportional to distance along the member?
Your second formula is true for a member of unit length.

Don't know if you mean beams because these behave differently to circular sections. What discipline?

HTH

they basically are replicas of airplane wings and we applied forces up to 200N to see how they behave. The explanation helped a lot btw, thanks mate, greatly appreciated :D

:D:D

I remember being up in the "bubble" of a 747, and looking out at the wingtip flapping away frantically. Made some concerned comment to my neighbour.

He said he was an engineering student, and once for interest they made calculations of the stresses applied to such wingtips.

He said once they got the answers, they no longer looked at wingtips through the window anymore :D:eek::D

<pendantic>

Shouldn't that be formulae?

</pedantic>

:p

I spent years watching wings twisting away all over the place-gave up watching in the end. At least I never had one let go!

The B52 bomber has the wingtips move upwards by some amazing distance during the take-off run until the wings can carry the weight of the aircraft. Can't remember how far now but it was fascinating to watch.

Les :)

Les, I've just re-read the Dam Busters by Paul Brickhill - he describes the first Lancasters taking off with the 10-ton Grand Slam bombs. Sounds a bit like those B52s!

In a former life I wrote a computer programme to iteratively calculate tortion and bending (due to lift forces) in helicopter rotor blades conforming to standard NACA profiles. I'll see if I can dig out the algebra behind it when I get home. With a bit of tweaking it could probably be used to do aircraft wings if you have the material properties.

Yep, what they said.

<super pedant>Actually the a and e should not be separate letters but a single character 'a diphthong' like æ </super pedant> :p:p

XT YHM.