LOCKHEED STRESS MEMO 53 & 140 mm (5.5") THK 7010/T7651

[StressMan2506]

Fellow Stress Engineers:

I am attempting to find mc/I per Lockheed Stress Memo 53 for 140 mm (5.5") thk 7010/T7651 material, but cannot find appropriate curves. Can anyone provide a source?

I have a poor-quality copy of SM 53; to my eye, p. 27 appears to cover similar material up to 2.0" thk. Is it possible to adapt these curves in some fashion? If so how?

Thanks in anticipation...

 

[RPstress]

Depends a bit on your final margin. The curves you mention are for 7075-T6, whereas you have 7010-T76. 7075-T6 is almost certainly a bit harder than your material, and so may be a touch non-conservative. If your part can stand it, you could use a curve for an aluminum that is demonstrably "soggier" than your 7010, and with a lower elongation to failure if possible.

Failing that, perhaps use an alternative method. Bruhn chap. C3 should work and is (as far as I know) universally accepted.

 

[StressMan2506]

Thank you, RPstress.

I have investigated the curves on p. 22 of Lockheed SM 53 as well as those on p. 27 and used the two sets to form upper & lower bounds; there is plenty in hand.

Do you have a clear copy of SM53 that you could make available?

Regards

 

[RPstress]

Maybe...I've got a 33 Mb .pdf file and I wouldn't call it "clear", but it's mostly adequate. If you can receive that let me know here with the usual sort of disguised e-address. I've tried to extract the relevant section to make it smaller, but Adobe Reader isn't making it easy. If I can shrink it I'll let you know.

 

[RPstress]

OK, I've got a 3.15 Mb file for just SM53d, if you want that.

 

[StressMan2506]

Thanks RPstress. I've not disguised an e-mail address before and I'm not sure how to go about it without making it obvious; tips please. The Eng-Tips recommended approach is to post the file to a public site and send the URL in an a thread message. I use Yahoo Briefcase where files can be private or public; I would guess that's the type of site that's meant by "public". The larger file can be transferred that way. What's the difference in quality between the two files?

 

[RPstress]

Most people seem to do something like put davedotphillipsatsomeplacedotcom rather than dave.phillips@someplace.com. (I hope there's no real dave phillips with that address...) That seems to be enough for now. If you know Unix it might pay to rot13 it. (And if you don't know Unix it's reasonably easy to do it yourself, provided whoever you send it to knows to try a rot13 and see if what comes out makes sense. See

http://www.rot13.com

. You can of course combine the two sorts of measures. There is also a rot47 which will snaggle up the dots and at sign.)

Both files are equally grungy. The extract is an Acrobat extract, so it should be pixel for pixel with the original (I didn't print the range of pages and scan or anything).

 

[StressMan2506]

Thanks RPstress. I'm in the UK and it's knocking off time. I'll try rot13 at home later (I don't have full internet here, only e-mail and access to a few specific sites such as eng-tips).

 

[StressMan2506]

Hi RPstress:

Please try e-mailing to =@F]42K62Fo2:C3FD]4@> & =@F042K62FoJ29@@]4@]F<. You might need

http://www.yousendit.com

or similar for the larger file.

Thanks

 

[midsidenode]

RPstress,

'you still have that SM53 document that you provided StressMan2506? I am also attempting to perform some mc/I in relation to SM88a and could really use it.

thanks
midsidenode