Cozzone Curves 6

[midsidenode]

thread2-110905
With reference to the past thread. Was that equation developed by McDonnell Aircraft in MAC339? I neither see it in Cozzone's "Bending Strength in the Plastic Range" publication nor in Lockhead's stress memo 53D.

msn

 

[midsidenode]

before i use that equation for determining fo, i'd really like to know a little bit more about it and who developed it - especially since i need to reference it in a report if i use it. MAC339 is one document that i've never been able to get ahold of. If the equation was indeed developed by Douglas and is only in MAC339 - does anyone know where i can obtain a copy of it?

 

[edbgtr]

MSN
As I know it, the derivation was developed by Eberwien et al and published in Germany at an Aluminium Association conference. I have replicated the derivation of the MAC339 formula for determining fo at any stress fm. The formula is also in a later revision of Bill McCombs' Bruhn Supplement.

You could also try the Cornell University website at Civil Engineering, work done by researcher Mr Kim, also for the Aluminium Association, who gives an indication how to perform the derivation.

Ed

 

[edbgtr]

MSN
The Cozzone derivation is attached.
Ed

 

[midsidenode]

I cannot find the formula in my copy of McCombs. But, I appreciate the derivation - thanks Ed

MSN

 

[edbgtr]

MSN and All
Thank you for the Star Kudos, much appreciated.
For completeness of my references, I tracked down Dr Ulrike Eberwien and obtained the original paper directly from her. The derivation in her paper is slightly different from mine but, with manipulation, it can ultimately provide the fo/fm formula as used in the MAC339 spreadsheet. Her paper is attached. It is more clearly laid out in the additional 2 attached Cornell University papers by Kim and Peköz. The key to the derivation is switching the y variable in terms of the strain, rather than the other way round.
Ed.

 

[edbgtr]

This system only seems to allow one attached file at a time.

 

[edbgtr]

And the third one!

 

[midsidenode]

Ed, thanks for being so thorough- much appreciated. Nevertheless, I'm having trouble opening the third reference on plastic bending. Can you upload it again?

msn

 

[edbgtr]

MSN
Hope you get it this time.
Rgds,
Ed.