This blog provides commentary on interesting geological events occurring around the world in the context of my own work. This work is, broadly, geological fluid dynamics. The events that I highlight here are those that resonate with my professional life and ideas, and my goal is to interpret them in the context of ideas I've developed in my research. The blog does not represent any particular research agenda. It is written on a personal basis and does not seek to represent the University of Illinois, where I am a professor of geology and physics. Enjoy Geology in Motion! I would be glad to be alerted to geologic events of interest to post here! I hope that this blog can provide current event materials that will make geology come alive.

Banner image is by Ludie Cochrane..

Susan Kieffer can be contacted at s1kieffer at gmail.com

Wednesday, July 9, 2014

Gorgeous Air New Zealand plane! (And, how much can Dreamliner wings flex?)

The new Air New Zealand Dreamliner; photo from CNN.com here
This strays from "Geology In Motion," but I can't resist--the Boeing 787 "Dreamliner" is truly a beautiful plane in flight! It's wings can flex up to 26' (150% of max load).  All aircraft are required by the FAA to be able to withstand at least three seconds of 150% maximum loads (on all structures). In January, 1995, a 777's wings deflected 24' at 154% max load (I couldn't find the actual data to check the facts--I'm using www. flightglobal.com.) Boeing actually did a break test, which you can see in this Boeing produced video. They do not say how flexed it was when it failed, however, only that it was beyond 150%! Here's a cool video (in German) of a lab test showing the flex in a way that you can actually see-it's huge--definitely worth watching this one all the way to the end to see the failure! Here's an explanation that I found on this aviation.stackexchange.com site:

"The amount of flex is really a product of the material. The wing requires a specified ultimate strength; with metal, that translates into a given amount of flex. This can be varied within limits, but it is really the material, its stiffness to yield point ratio, and its fatigue properties, that control how much flex you are going to end up with. CFRP is a very different material, and has much less stiffness for the same yield point, and has essentially no fatigue problems. This is beneficial in that it provides a smoother ride in turbulence; the wing acting essentially like a giant leaf spring. There is some lift lost due to the nature of the curvature, though. However, this is relatively small."

No comments: