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sl8rbaby
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Homework Statement
Two overlapping metal plates are bolted together with 12 bolts. The diameter of each bolt is 8mm. If the ultimate shear stress of the bolt material is 300MPa determine what factor of safety applies if the total force to be carries by the joint is 20kN.
Homework Equations
Stress = force/area
factor of safety = ultimate stress/actual stress (I think)
The Attempt at a Solution
stress=force/area
stress=20kn/∏r^2 x 12
stress=20,000N / (∏ X 0.004)^2 X 12
= 10.55 MN/m^2
factor of safety = ultimate stress/actual stress
factor of safety = 300MPa/10.55 MN/m^2
= 300 x 10^6 / 10.55 x 10^6
= 28.42
Is this correct, cause I am not that confident? also what is the unit? is there one?