Lug analysis curves

[pipsqueek]

Can anyone guide me to lug analysis curves with titanium data, this is for a certification project so the data must be public property or published to the public, many thanks

 

[edbgtr]

Hi Pipsqueek

I have waited a few days before responding, to see whether anyone on this forum has a source of public domain Ti lug
stress concentration factor data for you. You will need Ti-specific Kt and Kbr curves for different Ti alloys and processes.


This data is generally available in proprietary combat aircraft structural manuals, and should be in general use now by the commercial manufacturers due to the material's wide use in under-floor seat beams designed to withstand the new seat emergency landing load requirements. I have not seen any yet, but some of the new SRMs may contain relevant Ti data that you can use.

If you don't have access to this data, performing a generally accepted structural substantiation report for certification purposes may be problematic.

May I suggest two possible approaches you can take.

1. Contact Prof Michael C Y Niu and see if he can let you have some of this data, which may have been released for public consumption by Boeing. His contact details are in his "Sizing" text book.

2. Obtain, by whatever means, proprietary design curves for Ti lugs, and use them for your design. Perform tests on specimens (the number depending on your certification authority's requirements) to substantiate the design.

A third possible approach is to use the most conservative Kt and Kbr values (from the published steel, 2024 and 7075 material data) depending on your W/D and e/D value in your design, and then test as per 2 above. This should only be used if joint mass is not critical in your application.

Let us know how you progress in your search for public domain Ti data.

Ed.

 

[edbgtr]

Hi Pipsqueek
While surfing for other crippling information, I found a public domain Ti lug design curve in the following document, at the URL given below.

http://www.astro.ucla.edu/~flitecam/flitecamFAAwebpages/

FAAManual/FAA_Manual/handbook.300.mech.pdf

Splice the above 2 lines into one and download using your favourite download software.
Regards
Ed.