## Bending moment acting on an aircraft rib

## Bending moment acting on an aircraft rib

(OP)

Hello friends, I am having trouble with the estimation of the bending moment acting on an aircraft rib. The method shown in the images attached was given by a teacher at the university. I know how to do all the calculations up until the bending moment diagram, there I am struggling, since that was I've drawn bending moment diagrams was to use the areas under the curve of the shear diagram, but for this case that doesn't seem to work, or maybe I am doing something wrong ( most likely).

I really don't understand where the bending values are coming from.

Thanks in advance my friends

I really don't understand where the bending values are coming from.

Thanks in advance my friends

## RE: Bending moment acting on an aircraft rib

Once you account for the skin shears your BM plots should make sense.

## RE: Bending moment acting on an aircraft rib

This problem looks suspiciously looks a student problem ?

another day in paradise, or is paradise one day closer ?

## RE: Bending moment acting on an aircraft rib

"...The method shown in the images attached was given by a teacher at the university. …"Regards, Wil Taylor

o Trust - But Verify!

o We believe to be true what we prefer to be true. [Unknown]

o For those who believe, no proof is required; for those who cannot believe, no proof is possible. [variation,Stuart Chase]

o Unfortunately, in science what You 'believe' is irrelevant. ["Orion", Homebuiltairplanes.com forum]

## RE: Bending moment acting on an aircraft rib

## RE: Bending moment acting on an aircraft rib

please note, student posting is not permitted.

another day in paradise, or is paradise one day closer ?

## RE: Bending moment acting on an aircraft rib

I enjoy seeing this stuff/been afraid to ask sometimes.

## RE: Bending moment acting on an aircraft rib

another day in paradise, or is paradise one day closer ?

## RE: Bending moment acting on an aircraft rib

## RE: Bending moment acting on an aircraft rib

Cheers

Greg Locock

New here? Try reading these, they might help FAQ731-376: Eng-Tips.com Forum Policies http://eng-tips.com/market.cfm?

## RE: Bending moment acting on an aircraft rib

another day in paradise, or is paradise one day closer ?

## RE: Bending moment acting on an aircraft rib

One takes about an hour to set up and seconds to run. The other takes about a month, but brings far greater satisfaction.

## RE: Bending moment acting on an aircraft rib

The F/S reaction is approx 1878N and the R/S is ~250N. The remaining ~255N comes out as the vertical component of the shear flow in the inclines.

At the front spar, it's just 3.56*260*260/2=120,328N/mm. (Matches)

At 332.5mm, the bending moment is 3.56*332.5*332.5/2-1878*(332.5-260)-4.06*sin(6.2)*(332.5-260)*(332.5-260)=58,310N/mm. (value quoted is 82,468N/mm)

## RE: Bending moment acting on an aircraft rib

## RE: Bending moment acting on an aircraft rib

## RE: Bending moment acting on an aircraft rib

Rather than think climate change and the corona virus as science, think of it as the wrath of God. Do you feel any better?

-Dik

## RE: Bending moment acting on an aircraft rib

Jp: for a wing in pure torsion, if there were no rib at this station, the macroscopic effect would be greater warping of the wing cross section (wing becomes more torsionally flexible), at a detail part level the onset of panel buckling would occur at a lower load.