Typical Pin Loaded Lug FE Analysis

[Stress_Eng]

Having worked in the Aerospace industry for a while, I’m under the impression the FE analysis of pin loaded lugs is a common occurrence. With todays FA software package capabilities in contact analysis, I’m interested to understand the standard approaches used in deriving the linear surface stiffness used in the over-closure penalty approach. I have an Aluminum lug loaded by a steel or titanium pin. With different materials, I’m considering using an effective modulus based on the Hertzian contact method. I’ve seen suggested factors applied to the modulus between 5 and 50. I’m interested to know if a more specific value can be derived. In addition, I would also be interested to know if a target penetration depth is used as a basis. Any suggestions would be much appreciated.

 

[rb1957]

not sure what "over-closure penalty approach" means, but sure model your heart ou, and verify results with testing.

is this a static or fatigue case ?

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[SWComposites]

Lug analysis should be correlated to lug test data. Going down the rabbit hole of contact stresses is probably not useful or appropriate. Lug analysis typically focuses on basic failure modes - bearing, shear out, net section, with test derived stress concentration factors for each mode.

 

[Stress_Eng]

This is very early days, and I’m currently exploring what details would need to be considered when undertaking an FE analysis of an axially loaded lug. If the task is to go ahead, the intention is to determine local kt factors under a unit load case. This is currently an information gathering exercise, after which decisions will be made on what direction to take.

 

[rb1957]

wow, there are just so many variables, and more so when you're trying to analyze for the variability of a production line. Whatever, this new analysis will need to be well supported by detail tests, and the method will need to be very well validated. If you're using this analysis for certification. If it is "just" for development work, to give some assurance that the design will pass the certification tests, then it's up to you guys what you'll buy off. But be careful if this analysis is used to substantiated production changes.

"Hoffen wir mal, dass alles gut geht !"
General Paulus, Nov 1942, outside Stalingrad after the launch of Operation Uranus.

 

[SpaceEngineer4]

take a look at the AF Stress Manual or Bruhn for some lug design and eval guidance. i would enjoy hearing if your fe analysis correlates with the results from this calculations.

~Robert

 

[Ng2020]

For most, lug static strength is still a variation of Hoblitt/Melcone/Cozzone.
FE studies may be used to augment this in specific applications.
For fatigue/DT, use of FE is a little more common, but is supported by test data nonetheless.