Question 3:
The 60 mm diameter solid shaft is subjected to the distributed and concentrated torsional loadings shown. Determine the absolute maximum and minimun shear stresses on the outer surface of the shaft and specify their locations, measured from the fixed end A.
Take :
AA = 1.57 m
BB = 0.87 m
CC = 1207 kN/m
Solution :
The internal torque for segment BC is Constant T_BC = CC Nm. However, the internal for segment AB varies with x,
T_AB - 2000x + AA = 0; T_AB = (2000x - CC) Nm
The minimum shear stress occurs when the internal torque is zero in segment AB.
By setting T_AB = 0
0 = (2000x - CC); x = [] m Ans
And
d = AA - x = [] m Ans
T_min = [] Ans
The maximum shear stress occurs when the internal torque is the greatest. This occurs at fixed support A where
d = [] m Ans
At this location,
(T_AB)_max = 2000AA - CC = []
The polar moment of inertia of the rod is J = pi/2 (0.03^4) = 0.405(10^-6)pi.
Thus,
T_max = (T_AB)_max c / J = (0.03)(T_AB)_max / 0.405(10^-6)pi = [] MPa Ans