PROBLEM-1 (Shaft)
The figure below shows the forces acting on a shaft carrying a pulley and two gears, which
are keyed with a profile keyseat to the shaft at C, B and E. The shaft is supported by unkeyed
journal bearings at A and D. The shaft material is hot-rolled AISI 1137. The desired reliability is
0.999 with safety factor $n_d$ = 1.5. (Ignore pulley's and gears' weights)
a) Calculate the external torques at C, B and E, and determine the internal torques at sections AB,
BC, and CE.
[4 marks]
b) Calculate the forces $F_{rB}$, and $F_{rE}$
[2 marks]
c) Sketch the free body diagram showing all forces in zy-plane and zx-plane. Determine the support
reactions, and draw each force and bending moment diagrams.
[8 marks]
d) Determine the resultant bending moment at sections A, B, C, D, and E.
[2 marks]
e) Using Distortion energy method, determine the necessary shaft diameter at sections A, B, C,
and D; $d_A$, $d_B$, $d_C$, and $d_D$.
[4 marks]
Total: 20 marks
