Given Bicycle crank are A 05 times 05 L 6 a 2 at theta 9

Given: Bicycle crank are A = 0.5\" times 0.5\" L = 6\" a = 2\" at theta = 90 F = 100 lbs at theta = 180 = f = 200 lbs at theta = 270 = F = 50 lbs at theta = 360 = F = 25 lbs Find the principal stresses?(for any angle)

Solution

Take the position at the lowest : Syy= 200/area= 200/.5*.5 = 800psi

Sxx=0

The bending moment here is 400 lbin

The shear stress Mc/I = 400* 1/4/[(1/192]=19200 psi

Hence from Sxx,Syy,Tyz can find principa stresses:

19604, -18804 psi