jan 2012 q3.jpg
I've solved everything up to part d). I generally struggle with questions on bolts and I'm really not sure how to tackle this problem.
τ = Tr/J, τ = 200MPa, T=1kNm
The Attempt at a Solution
I worked out the separation of the bolts (I think).
Circumference around the inside: 2π(25mm) = 0.157m ∴ Separation: 0.157/2 = 0.0785m
Not sure where to go next, if I'm honest. I tried this:
T = 1kNm ⇒ F = 1kNm/0.0785m = 12.7kN
so σ = F/2A as double shear so A = F/2σ = 12.7kN/2(200MPa) = 3.19x10-5m2
so πr2 = 3.19-5 ⇒ r = 3.18mm ⇒ d = 6.37mm
so I went wrong somewhere as the answer is 11.28mm
any help appreciated. Thanks