How to build flex wing

[PlatinumZealot]

So exactly how do you build flex wings? Lets go beyond the normal "laminate orientation" answer.

A man would be very rich with Ferrari and Mclaren money he could answer that one.. but I think it's fun to try to come up with some ideas.

[hardingfv32]

Yes, show one creativity?

Brian

[shelly]

This is well known. Now how do we get a non-linear response in a beam from a linear load application?

Brian

Maybe we do not need to be non linear. Just ortothropic behaviour and bending under torsion load will do th job.

If we look for a soultion tht behaves non linearly under vertical point load propably we can not find anything. If we compare point oad with distributed load+ torsion than we can draw some conclusions.

[hardingfv32]

1) On the face of it it would seem very easy for the teams to design a beam (wing) with linear response that meets the tests required at this time. It would just seem that is not what RB is up to if everyone else has such a hard time matching their flex levels.

2) Regardless of the validity of the above statement or any other opinion on the flex wing subject, the challenge has been stated for this thread as requiring a non-linear solution.

Brian

[hardingfv32]

Tim W,

I thought about your proposal and i am not sure it is valid. I do not think that the beam section having bends in them would create a non-linear response. What properties of the bends has an effect on a flat spring's linear response.

Your dual beam structure has merit. It would seem that we need a lower beam that is capable of going over center. (Is there a better term?) Do Belleville discs have this property as an example?

Brian

[Tim.Wright]

Brian,

All three images there are of the same system. The bend in the beams is not to introduce the non-linearity, but just to impose a pre-load between the top and bottom beams at the static design position.

The nonlinearity is due to the plates separating. At that point the total stiffness drops because the top plate is no longer doing anything.

I dont quite follow what you mean by going over centre. Keep in mind that the geometry in the picture is greatly exaggerated to show the idea. The bends in the plates (which could also take the form of a gentle curve) would only be a few mm in magnitude.

Tim

[hardingfv32]

I did not appreciate that the two members separated in the "C" illustration.

Question: I don't see how the separation of the upper element in "C" helps increase downward deflection. It would seem like the top element would be needed to get a non-linear increase in movement. This layout could in fact be non-linear, but it would seem to be the opposite of what we are after.

Where am I going of track?

Brian

[Richard]

Tim, I don't think that works as you describe.

All the load is carried by the bottom part, the top part merely applies a pre-compression load but doesn't carry any of the externally applied load.

Hence the deflection is always dependent on the stiffness of the bottom element, and that is constant.

[marcush.]

what about a rectangular crossection solid beam -made of carbonfibre or dyneema which is thin but tall in crossection ? the beam runs along the spanwidth of the wing but has no connection to the skin.
As you bend the wing downwards the beam resists the bending force up to its buckling load but then suddenly it twists to the side and voila we got a soft wing.As the load reduces the beam will go back in its upright position .
There are millions of possibilities to preload restrain enahance this behaviour by stops reduced/ incresed /thickness or the ways you fix the beam to the end plate to get a certain charecteristic..
Of course you need to build the outer skins flexible enough to bend ..so no foam core or honecomb.

[Richard]

As the load reduces the beam will go back in its upright position

That's the tricky bit, it would need a material that didn't have any plastic deformation or yield when buckling.

[marcush.]

As the load reduces the beam will go back in its upright position

That's the tricky bit, it would need a material that didn't have any plastic deformation or yield when buckling.

Maybe I put my words incorrectly.I try to explain again:

Take a strip of steel 2mm x15mm around say 800mmlong and load it with a vertical force at some force the strip will simply go in torsion and show elastic bending .There is no plastic deformation involved in this .You just use the geometric stiffness advantage of putting the strip in a upright position and as you do not restrain it from bending sideways under the normal load it will inevitably at one point assume a torsioned attitude and allow the beam to bend under load.

[shamikaze]

hi,

I think that RB is very creative in applying FIA's test-method and the contruction of the FW test-adaptors. The FW-adaptors are to be provided by the team and have to match the specific place on the FW as indicated by the test. This means that the full 100kg will be applied on the face of the FW (bottom part/lowest element) and probably not on the higher elements.

Therefore, this could potentially block a "sliding" of different layers/elements within the contruction of the FW, that doesn't get loaded when the wing is subjected to aero-pressure which distributes the load more evenly rather then point-pressure. This could prefent the FIA from detecting what's going on with the FW when it's loaded under normal load rather then point-load even though when on the track, it's clear for all to see.

Rather then using adapters, they should attach suction (ie vacuum and pull downwards with the correct and measure the deflection. The vacuum-holder should have a surface long and wide enough to assure it doesn't break the layup between the different layers of carbon/epoxy, but it will make the test equal for all, irrespective of shape of the wing. Eliminating any possible contruction influence in the shape of the adapter and smart construction of the FW to be activated/deactivated when the adapter is attached.

Obviously, this is just an idea based on how smart RB has been on working "around" the tests and testing-methods rather then sticking to them I think this is an achievable way of faulsifying the test-results if you would construct a flexi-wing with seperate layers that would be able to move relative to each other.

GReetz,

S.

[marcush.]

I think the upright beam method would be very useful in meeting the FIA test requirements (the test load could be used to clamp the beam and prevent from twisting for example)

[hardingfv32]

To eliminate testing effects we will restate the problem again as: How to build a flexing rectangle structure (thick plate?) with the same outer dimensions of a F1 front wing that has a non linear flex rate when acted upon by a linear increasing load. Make it a mechanical test. Purely a structural problem, no aero.

Brian

[marcush.]

To eliminate testing effects we will restate the problem again as: How to build a flexing rectangle structure (thick plate?) with the same outer dimensions of a F1 front wing that has a non linear flex rate when acted upon by a linear increasing load. Make it a mechanical test. Purely a structural problem, no aero.

Brian

Brian,my idea only works with a hollow structure as I need the beam to be free to go into torsion.It´s a pure mechanical issue with no separate parts ,the trick is just were to join and interlock the internal structures under which loads..
well.not really I cut put my beam on top of the solid plate structure just as well...