1. A marine propeller shaft is to transmit 3.

7 speed of 550 rpm, determine the torsional

MW at 126 RPM without exceeding a stress developed on the 50 mm motor
torsional stress of 42 MPA or twisting shaft. ANS: 5.287 MPA
through more than 2 degrees in a length 11. Two shafts are connected by a flange
of 20 diameters. Determine the shaft coupling and is secured by 6 bolts, 20 mm
diameter. ANS:324 mm in diameter on a pitch circle diameter of
2. Steel railroads rails 10 meter long are laid 150 mm. If a torque of 120 N-m is applied,
with clearance of 3mm at a temperature determine the shear stress in the bolts.
of 15 degrees C, at what temperature will ANS: 0.849 MPa
the rails just touch? In addition to this, at 12. A shaft that transmits 130 kw at 1250 rpm
what temperature will the rails develop an had a rectangular key used in its pulley
axial stress of 150 KSI? ANS: 40.64 C, 468 connection. Considering that the shearing
C stress of the shaft is to be 47 MPA and the
3. A hollow column with di=1/4 do is to key to be 206 MPa, determine the width of
support a dead load of 35 tons, the the rectangular key. ANS: 11.891 mm,
material is steel at 1500 C, determine the 17.047 mm
outside and inside diameters using a yield 13. A flange coupling is to be designed using
strength of 125 KSI and a design factor of 25 mm diameter bolts at a distance of 152
5. ANS: 1.375 in, 0.344 in mm from the center of the shaft, allowable
4. A steel railway track 11 km in length is stress on the coupling is 103 MPA. If the
laid at a temperature of 15 degrees C, if flange is 28 mm thick and the shaft is to
the track is to slide forward, how far apart be transmit 5800 HP at a speed of 1200
will the ends of the track be in ft when the RPM. How many bolts are needed in the
temperature is increased to 69 C. ANS: connection? ANS: 4
36,113.80 ft 14. A solid steel machine shaft with a safe
5. A solid circular shaft is used to transmit shearing stress of 7300 psi and transmits
200 HP at 1000 RPM. If a hollow shaft is a torque of 12,500 lb-in. A square key is
used having an inside diameter equal to used whose length is equal to 1 ½ times
the diameter of this shaft, if the angular the shaft diameter. Find the key
trust of the hollow and solid shafts is to be dimensions. ANS: 0.515 in, 3.087 in
equal? The allowable maximum shearing 15. A flange bolt coupling of 8 ¾ in diameter
stress is 20,000 PSI, determine the inside bolts spaced evenly around a bolt circle of
and outside diameters of the hollow shaft. 1 ft diameter. Determine the shaft
ANS: 1.475 in, 1.8 in diameter if the allowable shearing stress
6. Wires with 7mm diameters and 9.5 m in in the bolts is 5300 psi and in the shaft is
length are used to suspend two masses of 7000 psi. ANS: 4.340 in
170 kg, one of the wires is steel and the 16. A flange bolt coupling has ten steels 1 in
other is aluminum. How much lower will bolts evenly tightened around a 415 mm
the mass held by the aluminum wire be? bolt circle. Determine the power that the
ANS: 3.98 mm connection can transmit at 650 rpm if the
7. A round steel shaft rotates at 200 RPM and allowable shearing stress in the bolts is 50
is subjected to a torque of 226 N-m. The MPA. ANS: 3578.50 KW
allowable shearing stress is 41.4 MPA. It is 17. A flange coupling connects two 50 mm
also subjected to a bending moment of shafts, the coupling has an outside
339 N-m. Find the diameter of the shaft if diameter of 200 mm. there are eight 16
it has an allowable tensile stress of 55 mm bolts on a 140 mm bolt circle.
MPA. ANS:41.039 mm Determine the shear stress in the bolts if
8. A round steel shaft transmits 50 KW and the flange thickness is 30 mm and if the
rotates at 150 rad/s. Find the angle of torsional stress in the shaft is designed to
twist for a 3 m long shaft if the allowable not exceed 27 MPA. ANS: 5.886 MPA
shearing stress is 40 MPA. ANS: 4.75 18. Two short shafts having identical
degrees diameters of 40 mm and rotating at 550
9. A hollow shaft with outside diameter of 14 rpm and connected to a flange coupling
cm and wall thickness of 0.8 cm transmits having four bolts within a 5 in bolt circle.
200 kw at 400 rpm, what must be the The design shearing stress of the bolts is
angular deflection of the shaft if the length 1.7 kips/in^2 and the design compressor
is 5 m. ANS: 1.136 degrees stress of the flange is 2.2 kips/in^2. How
10. A pump is connected to a motor by means thick should the flange be in mm? ANS:
of a coupling. The pump capacity is 4 cum 10.77 mm
per minute of water against a head of 5 in.
If the efficiency of the pump is 70% at a
19. Kindly solve for the power of a line shaft,
which has a diameter of 1.5 in rotating at
200 rad/s. ANS: 120.482 HP