Pin Design 1

[Badri07]

Hi All,
i have designed a pin (which has got circular cross section),thats going to be in shear,i have assumed the pin to be short coloumn and considered only shear.

I did try to do some basic bending stress calculation ,but the bending stress is way above the allowable,while shear stress is below the allowable.

I am bit confused about this reponse.i thought short coloumns fail more due to shear than baending.
i appreciate your comments on this.

Thanks
Badri07.

 

[rb1957]

so i think you've modelled the pin as a beam, 10" long with a 250ton load applied on CL. simply supported, max moment = 250*2240*10/4 = 1.4E6in.lbs = 158E6Nmm. with 5" dia pin, I = 30.7in4; max stress = 114ksi (not too bad) hollow out the pin (ID = 4"), I = 18in4, max stress = 193ksi (a bit high)

but consider, model the beam as 7" long (assume the reactions in the outer plates are at 1/4 thickness). assume the load is applied in two concentrated forces 0.5" from the mating plane (mirroring the outer plates reactions). now the max. moment = 125tons*1" = 280E3inlbs. (1/5 of the previous moment) now the max. stress of the hollow pin is only about 40ksi.

this isn't a complete analysis, but you can see how conservative your original assumptions are.