Deciding Number of Fasteners

[CaKa]

Hi There,

Nowadays I'm having some problems about fastener sizing and I thought Eng-tips can give me a hand. I'm designing a simple shear panel which is connected to C profiles from edges. For better imagination you can have a look to my sketch,

http://prntscr.com/4qksim

Also I have some supporting profiles one edge to other edge along panel. Usually I was using RBE or BAR elements to present fastener connections now I've tried to check shear force distribution, you may have a look to it from below

http://prntscr.com/4qku93

it's shell force resultant as N/mm, I used maxshear results from nastran. As the pitch distance 40mm, I have 25 fasteners per meter. Since the shear allowable is 8KN per fastener, my shear allowable is about 8*25=200KN/M (or 200N/mm). So with this method I need to increase fasteners 2 times which is not sounding realistic. Also I have tried some freebody methods but because of my profiles are equivelenced it's not possible to have proper result via freebody methods. I wonder can you suggest me a method to size my structure in sense of riveting.

 

[BenoitJ]

If I was faced with the situation, I would begin with a transverse shear calculation to determine the shear on the fasteners. The geometry is not that complicated. Then you can compare the results to your fea results to see if you are in the neighborhood. At that point you might have no choice but to go to a weld or increase the number of fasteners or the size of them.