Question

The figure shows a transmission shaft. The steel solid shaft is 200 mm long between self-aligning bearings at A and B. Belt forces (in the same horizontal direction) are applied to a 120-mm diameter sheave at C. The left end of the shaft is connected to an electric motor attached to a clutch by means of a flexible coupling. Nothing is attached to the right end (it is free). Assuming the shaft has a constant diameter, d, (a) Perform the necessary stress analysis and draw the critical stress element (b) Using stress element and Mohr circle approach, find the principal stresses and the maximum shear stress. (c) For a factor of safety of 2, and material made of plain carbon steel (AISI 10XX), specify a safe diameter d and a material for the part 100 Free end of shaft 3-mm- 1. shaft 100 2000 N A sheave is a pulley with a grooved wheel for holding a belt, wire repe, or rope. The grooved wheel spins inside the frame of the heave. This allows the wire or rope to move freely minimizing wear and abrasion on cable. Sheeves can be used to redirect a cable or rope, lift loads, and transmit power Source Wikipedia. 120-mm-dia sheave 400 N Connected to tiexible coupling and clutch

Answer 1

The torque acting on the shaft is calculated. This calculated torque will be the torsional moment on the shaft. The free body diagram on the horizontal plane is prepared. The reaction forces at the fixed ends are calculated. The shear force diagram is prepared after that. Once the shear force diagram is obtained, the Bending moment diagram is then prepared.

The bending stress is calculated for the maximum bending moment. Similarly torsional shear stress is then computed for the given torsional moment or the torque. The stresses acting on the elements are then shown.

For the calculated stresses or the bending or the torsional moment, the principal stresses can then be computed. The maximum torsional shear stress can also be computed.

For a factor of safety of 2, assuming the material to be AISI1040, the safe diameter is then calculated.

Note: The diameter of the shaft was not clear in the image, so all the stress calculations are done assuming it to be 30mm.