aircraft outer cap frame fasteners load extraction... 1

[051174]

How to extract correct outer cap frame fastener loads by a Global FEM rapresenting aircraft in the current manner:
_________
|____|____|
|____|____|

|=frame as cbeam
___
___= skin panel 1 stringer bay CQUAD

In general for frame fastener load i use cquad xy shell force extraction for left and right side and considering the difference between these obtaining a delta flux.multipling by stringer peach.dividing for # fstnrs.
But i'm in doubt about it because fastening can suffer also load coming from the height of the frame that could give an additional load on outer cap fastening.(as frame shear load).The cquad delta flux method can be ok for stringer fastening load extraction but not for frame.The section inertia can influence the method. What is the correct way? there is a bibliography or someone can give me the correct way to obtain it. Thank you in advance.

 

[rb1957]

IF there is no skin splice, then i think the frame outer cap rivets react the frame web shear.

there is a detail point about the frame outer cap axial load, the frame frame is discontinuous and really acts as a shear tie for the frame but i'll bet that the frame outer cap is included in the outer cap FE, so really a portion of this load is being sheared into and out of the frame outer cap over the attachement between two stringers. The portion would account for the fact that most of the outer cap is the fuselage skin, maybe skin reinforcement at the frames ... basically it'd be an area ratio between the entire outer cap and the effective skin.

IF there is a skin splice, then these rivets reacts the difference in skin shear as well. also all of the skin axial loads.