franc11HD
New member
- May 4, 2011
- 50
Hi,
Got a question here about Supplement A in Bruhn lug Analysis (D1.13a).
If I understand correctly, this states that knowing the axial strength of the lug (Min of Pbru or Ptu) the transverse allowable can be approximate by Fig. D1.15a. This (as written in the text) is based on ''great number of tests and with different materials.''
Now, looking at the figure, it shows that the transverse strength (90 degrees) shall be 75% of the axial allowable.
But heres the catch. If a do the hand calculations based on Lockheed stress memo or boeing design manuals (which are also based on many tests for different materials) I end up getting transverse allowable between 17% and 36% of the axial strength. Doesn't that contradicts clearly Bruhn Supplement A? The difference is major. Using Bruhn, I would overestimate the strength.
Is there something I misinterpret?
Got a question here about Supplement A in Bruhn lug Analysis (D1.13a).
If I understand correctly, this states that knowing the axial strength of the lug (Min of Pbru or Ptu) the transverse allowable can be approximate by Fig. D1.15a. This (as written in the text) is based on ''great number of tests and with different materials.''
Now, looking at the figure, it shows that the transverse strength (90 degrees) shall be 75% of the axial allowable.
But heres the catch. If a do the hand calculations based on Lockheed stress memo or boeing design manuals (which are also based on many tests for different materials) I end up getting transverse allowable between 17% and 36% of the axial strength. Doesn't that contradicts clearly Bruhn Supplement A? The difference is major. Using Bruhn, I would overestimate the strength.
Is there something I misinterpret?
