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Hi, Thanks everybody for the replies. I have provided more detail in the attached sketch. What is interesting for me is that there is no established method to transfer the torsion loads through the fasteners to the skin. For transverse shear, we have a V*Q/I x pitch type approach. I can...

Hi rb1957, I have attached a sketch of the assembly as per your request. I have thought of applying the torsional moment as differential couple force and splitting the shear force according to relative area-as you suggest. But there must be a more analytical method...using the shear...

Hi all, I am trying to find a method of fastener shear transfer between a thin-walled open U-section and skin (both are aluminium, with skin attached on both sides of the vertical walls). From the grid point force balance output from the FE model, I know what torsional moment is being carried...

Ng2020, you are a genius! I see where I went wrong: 1. I assumed from Figure 6 that there is a friction force also applied at the NLG-which I see only now applies if the NLG has brakes. Do you know perhaps if the A330-300 has brakes at the NLG? 2. I worked through the problem with the dynamic...

3DDave-I tried that. I still do not know where the μE term comes from in the denominator. Can you post your worked solution?

No berkshire, I was being facetious. I really am struggling to rework this equation and could use some professional help. Seems like all I'm getting is criticism...

Oh @Sparweb, master engineer, please forgive this dumb question from a lowly underling, and please also provide a worked solution-so I can finally pass 1st year mechanics.

Hi, FAR § 25.493 (e) states an equation to calculate the maximum nose gear reaction in a braked roll. I cannot for the life of me back-engineer this equation-and it seems so simple. If anybody could show me how to calculate it, I would be most appreciative. Here is the relevant excerpt and...

I did an investigation, and the Schijve method outlined in his 2009 paper for both doubler and skin of same thickness (0.04" and then 0.05") yielded bending factors k = 0.626 and 0.553 respectively. When I increased the thickness of the doubler to 1-gauge up it shot up as expected. Safarian's k...

Interesting 'take' on Swift. I hear your points. Another opinion: there are differing sources for secondary bending; I'm thinking of Safarian, Schijve (neutral line) etc. Which one do you advise using?

Great point about the stringer's 'day time job'. Also, while I have your ear, what is your opinion on the secondary bending moment transferred by a CSK fastener? Statically, this moment is high, but is it realistic? Also, what is your opinion on tab-outs/ fingers/fish mouths at the first row...

Hehe rb1957. On that note, I understand why the last row ending off the stringer is better for inspection, but why oh why is it better for anything else, The area of the doubler compared to the skin is larger off the stringer and therefore it draws more load... am I missing something here.

Sorry for the long delay. Thanks for all the great advice. LiftDivergence, thanks for the great reference. SparWeb, sorry for the embedded file-I'll know for next time...

Thanks LiftDivergence, This is a pressurised structure, and an STC. It's a low aspect ratio antenna, so the skin/doubler combo panel can handle the out-of-plane bending loads, even superimposed with global loads. Is replacing the doublers with one large doubler the only viable option...

Thanks for all the useful feedback. Valid points made about the altered stress field in the skin due to the many repairs. I attach a sketch of the problem and would love to know everyone's advice and thoughts further. To clarify things, I'm working on adding a small antenna to the belly of...

Hi, Is there a general "rule of thumb" that addresses the amount of doubler repairs that are allowed on a fuselage skin, specifically for FAR23 a/c? Something like a density requirement. I know that some OEMs (FAR25) mandate a full stringer frame bay surrounding a 'significant' dent must be...

Hi, This is a follow on to thread2-122412. I am installing a SATCOM antenna on the top fuselage of a pressurized commercial jet. I am relatively new to this field, and have the following questions that I hope the experts can advise me on: 1. The doubler used to reinforce the skin, shown in...