Assignment-1
Q1. A solid machine shaft 40 mm in dia. Transmit a torque of 1500 N-m. A square key is used
whose one side is equal to 0.40 times the dia. of shaft and whose length is equal to 3.2 times the shaft
dia. Find the dimensions of the key and check the key for its induced shearing and crushing
stresses. Obtain the factor of safety of the key in shear and crushing when yield stresses in shearing
and crushing are 450 N/mm2 and 625 N/mm2 respectively.
Q2. A solid shaft is subjected to a bending moment of 6.46 kN-m and a torque of 18.5 kN-m. The
shaft is made of carbon-45 steel and factor of safety is 5. Determine the diameter of shaft. The
ultimate tensile strength of c-45 is 670 MPa.
Q3. Design a double riveted butt joint with two cover plates for longitudinal seam of a boiler shell
0.70 diameters to carry a maximum steam pressure of 1.05 N/mm2. The allowable stresses are σt
=3.5 N/mm2, ζs =28 N/mm 2. Assume the efficiency of the joint is 75%.
Q4. Two shafts 100mm, diameter is to be connected by means of two cast iron couplings. The
allowable shearing stress of the bolt material is 45 N/mm2, while that of the shaft material is 55
N/mm2. Find the size of the bolts to be used. Check the flange for the induced crushing stress. Is
safe stress?