Lug analysis as a cantilever beam
Lug analysis as a cantilever beam
(OP)
Hi,
I'm reading a single lug stress analysis. The theory being used is not familiar to me. I was expecting an analysis based on what we can find in books like Bruhn and Niu. When using this method, the margins of safety were very negative. So what they used is an analysis considering the lug like a cantilever beam with a load transfer around the lug and calculating a maximum moment at a section 45 degrees from transverse direction.
Does it ring a bell to anyone? I never heard of all this and since it's the only way the lug could have a positive margin of safety, I would like to know if it is relevant.
Thanks you very much!
I'm reading a single lug stress analysis. The theory being used is not familiar to me. I was expecting an analysis based on what we can find in books like Bruhn and Niu. When using this method, the margins of safety were very negative. So what they used is an analysis considering the lug like a cantilever beam with a load transfer around the lug and calculating a maximum moment at a section 45 degrees from transverse direction.
Does it ring a bell to anyone? I never heard of all this and since it's the only way the lug could have a positive margin of safety, I would like to know if it is relevant.
Thanks you very much!





RE: Lug analysis as a cantilever beam
RE: Lug analysis as a cantilever beam
RE: Lug analysis as a cantilever beam
RE: Lug analysis as a cantilever beam
For a simple lug you should be able to do a simplistic analysis of it from first principles to compare.
You've got the tear-out, the Brunelling and fracture across the hole.
If I recall this is summarised in a work sheet from I think it was Folland aviation, probably not something you have to hand.
RE: Lug analysis as a cantilever beam
I've just read ESDU 91008 : Lug strength and their approach is exactly the same as in Niu or Bruhn. Maybe there's another ESDU I didn't find.
But Niu and Bruhn propose to analyse the lug as a cantilever beam if Ktru or Ktry fall under an approxiamte cantilever strenght curve, but they do not show how to make this analysis. But this seems to be a very rare case.