July 2009

Jeff,

I thought I'd share with you some of my experiences so far this summer at my internship so that you could share it with some of your students. I think many of them would be quite surprised to know how much Mechanics of Materials is used in every day stress analysis here at Spirit Aerosystems and companies like Boeing, Airbus, Rolls Royce and even GE. Unfortunately, I can't actually send you any pictures or any documents I've written (which has been a lot, I've written about 4 reports so far, each being about 30 pages. As well as revising and editing other stress analysts' work.)

Anyways: One of the things I didn't realize until I started work this summer was how much parts are often modeled as a simple beam problem. Almost everything I've done. No scratch that, Everything I've done, has been modeled in some way as a simply supported beam. I'm currently working on the Rolls Royce BR 725 engine for the new Gulfstream G650. (See attached picture) I'm working on the thrust reverser of the port side engine, doing stress analysis on one of the main bulkheads. Most of that work consists of me analyzing parts that have been attached to the main bulkhead. Everything attached to the engine must be able to survive different loads. (vibrations etc.) And to prove that they do we model it as a simply supported beam experiencing some sort of load with a factor of safety.

But this is what I think most students don't realize. Almost everything I've looked at has shear and moment diagrams. And I do mean everything. MY/I gets used daily. I have massive spread sheets created to help calculate moments of inertias, centroids etc. Its pretty intense how much is developed. There's also a lot of Finite Element Analysis done but its always validated by some sort of hand analysis. Oh, and Roark's Stress and Strain is on every stress guys' shelf. (Btw! Tell Dr. Philpot that I get asked if they can borrow my Mechanics of Materials book daily. They all think its an amazing tool. well Except for the lack of beam tables in the back, but other than that they love it)

Composites are huge here as well. We have the second largest autoclave in the world. I stood in it last week. Its big enough to fit an entire 787 dreamline nose section in (the 787 has an all composite fuselage). Its 40 feet long with a diameter of 22 feet. Its massive. You really feel insignificant when you stand inside it.

Again, I wish I could send some pictures of our autoclaves (There might be some on the net though) and other things we do here. I just thought I'd show how important Mechanics of Materials is to the Aerospace Industry as well as other industries. Without it we wouldn't be able to do the things we do. (And I'd be out of a job!)

Tim XXXXXX
Aerospace Engineering
Missouri S&T