bot6 wrote:There are plenty of other solutions for the load test. One would be to load the wing in three places along its chord instead of just one at the moment, which would make it impossible to just place the pivot point of the wing flexing where the test load is.
Well, with all due respect I think it's not a question of more points.
I think that now the problem is this: the
FIA test assumes that the wing flexes proportional to load.
I am no mechanic but I know
my structures.
I can give you three solutions (at least) to
give you a flexing that is not proportional to load once you pass a certain threshold. This wing is not elastic.
One is what I would call the
silly putty solution. You know, silly putty is not elastic nor plastic either, but thixotropic, as
asphalt is: the deflection depends on the speed of the loading, like ketchup, that doesn't move until you hit it hard. If you make a ball with silly putty, you can make it rebound from the floor if thrown against it (with a quick load) but it also will stretch like bubble gum if you pull it with a sustained load, while it "melts" under its own weight if you leave it on a table.
Wonderful substance silly putty is and all structural engineers can learn a lot by buying a bit and actually watch it at work... believe it or not, the textbooks about elasticity are kind of naive, because all materials have a bit of that, but none is as instructive as this unnoticed material.
That's the reason why at toll booths the road is made of concrete, even if the rest of the road is made of asphalt: when the heavy trucks stop, they damage more the asphalt, because the asphalt creeps under a sustained load, even if larger impact loads do not affect it. Actually, this is the opposite of ketchup, but you get the point. So, parking lots for heavy trucks and every surface where the trucks will be stationary needs a thicker asphalt layer or a more rigid one. The Shell design book for asphalt explains it very well.
Second would be a simple plastic solution, which would be harder to implement, if possible at all, because you couldn't recover easily from deflection, which would be more or less permanent, so you should evaluate how much the "final creep" would be.
Third would be to use a two or three point compensated hinge, like the old submarine hatches that you could move with one hand (a spring is giving you a compensation of turning moment, if you get my drift). Piccard explains it very well in his book about the batyscaphe he built in the 1950's, when he shows how he built the main hatch, able to resist 11.000 meters of water pressure, but that you can move easily in case you really feel an urge to exit the batysphere.
This is the way some kitchen doors work (you know, those doors in kitchens that resist you pushing them until a certain point is reached and then you "overcome" the spring, then they move away and "cross" toward the other side of the entrance, where the spring kicks in again, they are used in every restaurant kitchen).
Actually, I would go for number three, or a combination of number one and three. They would be undetectable, even if you use a dozen points.
I bet a rum bottle on this happening.
So, I guess they have now a new field of research. More money down the drain. Sheesh.
The simple solution from the point of view of stewards, as all solutions that are simple are, is not to use an indirect method of measurement, but
something that measures directly the outcome. I would suggest something like the plank, that has worked very well for many years to control body clearances.
You cannot beat the designers, if they are using these solutions (and I believe they are clearly using them) by changing the simple test FIA uses nowadays.
I hope this is clear. I would love to hear criticisms of this possibility. Heck, if they are not using this system, they should.
I would, and if they are not using it, then they have it here.
Talk about selective reading. I said the measuring is not straight forward to solve. Nothing to do with the overall problem of the flexing wing
