friction stir welding - wing skin
friction stir welding - wing skin
(OP)
Is FSW possible for the wing skin on large (like 747) aircraft. The stress on the lower skin during deflection testing must be concentrated on discontinuities such as rivet points. I would think the overall thickness of the skin could be reduced if these weak points weren't there, saving tons of weight. What is the typical thickness of the skin of the lower wings of these large aircraft. Is is usually 2024-T3?





RE: friction stir welding - wing skin
Brian
www.espcomposites.com
RE: friction stir welding - wing skin
a concern with usig FSW on wings would be the very HCF environment and the very flexible structure ... a fuselage sees one big fatigue cycle per flight (with a whole bunch of small gust cycles superimposed) and very small deflections.
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
- 747 wings are really, really large so process scale-up is not going to be trivial
- discrete (fastened) stiffeners and spar have significant benefits for damage tolerance with fatigue cracks
- due to damage tolerance considerations, the weight savings is not what you think if might be
- if the weight savings really was "tons of weight" the process would have already been used
- you have to design for repair, which means fasteners, so you have to design for fastener holes anyway
RE: friction stir welding - wing skin
Maybe I'm thick too, but...
RE: friction stir welding - wing skin
I.e., an additive process instead of a subtractive process like milling.
Mike Halloran
Pembroke Pines, FL, USA
RE: friction stir welding - wing skin
however you need to be careful that you don't make the structure "unrepairable" ... (by not providing sufficient material to discretely attach repairs)
that said, it'll be interesting to see how Boeing repair the 787 (and Airbus the 350 ?) once in-service damage starts ... bonded repair dblrs ??
RE: friction stir welding - wing skin
I thought FSW was inherently a _butt_welding process which limits it to joining the edges of two sheets of possibly different thickness, or joining the edge of a sheet to the edge of a flange.
So I didn't see how you could use it to attach a sheet to the _face_ of a flange, i.e., making the joint repairable with rivets.
But Wikipedia says there is such a thing as a FS _spot_ weld: "Friction stir spot welding is successfully used for the bonnet and rear doors of the Mazda RX-8 and the boot lid of the Toyota Prius."
I found an AWS paper with photos of FS spot welds.
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The tool side of the spot weld has a large cavity, not unlike a Tog-L-Loc joint in appearance. Not the sort of thing you'd want to have on aircraft skins.
Still promising for terrestrial applications.
Mike Halloran
Pembroke Pines, FL, USA
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
- bonded scarf repairs
- some bonded doubler repairs
- some bolted repairs
RE: friction stir welding - wing skin
My guess is that bolted repairs will be the common choice, at least initially. Bonded doubler repairs are good, but only address certain types of damage. Scarf repairs have proven to be difficult to do with a high enough level of confidence, even at production facilities. It is going to be even a greater challenge outside of that environment. I think the initial thought was scarf repairs might be a first choice, but that seems to have changed.
However, after there is more confidence and need for bonded repairs, I suspect the trend may change from bolted to bonded.
There are some other things as well and some details I have intentionally left though. Sorry to get off topic.
Brian
www.espcomposites.com
RE: friction stir welding - wing skin
FSW can also be used to produce a linear suface weld between a sheet and underlying support. The rotary bit just needs to extend into the support piece and it will stir the two materials together in a super plastic phase. I think Eclipse Aviation was working on qualifying this process, though I must admit I only know what I've learned from technical literature. I did a report on it in college, which does not make me an expert.
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
RE: friction stir welding - wing skin
It seems the rocket industry has been making use of this method for awhile. Most recently the Orion team has been trumpeting FSW fabrication.
Same question for circumferential welds - how can they be continuous?
http://ww
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RE: friction stir welding - wing skin
I think they do start at a free edge. And as for circumfrential welds I saw a video of one where after the weld was started, they mig welded a runoff plate before it got all the way around. That was for a steel pipe and it looked like a university research lab.
-Kirby
Kirby Wilkerson
Remember, first define the problem, then solve it.
RE: friction stir welding - wing skin
Axles for bulldozers are frequently friction welded and don't seem to have problems with fatigue. That is one of the benefits of this method.
TOP
CSWP, BSSE
www.engtran.com www.niswug.org
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