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10000ME401122002

Design and draw a knuckle joint to connect two mild steel rods to transmit a tensile
force of 25 kN. The safe working stresses for tension, shear and crushing are 100
N/mm’, 60 N/mm? and 160 N/mm? respectively.
A single riveted double cover butt joint is made in 10 mm thick plates with 20 mm
diameter rivets with a pitch of 60 mm. Calculate the efficiency of the joint.
The allowable value of stress in shear, tension and crushing are 80 MPa, 100 MPa
and 160 MPa respectively.
PART C

Answer any two full questions, each carries 20 marks.
Obtain an expression for the maximum shear stress induced in a spring wire.
A helical compression spring made of oil tempered carbon steel is subjected to a load
which varies from 400 N to 1000 N. The spring index is 6 and the design factor of
safety is 1.25. If the yield stress in shear is 770 MPa and endurance strength in shear
is 350 MPa, Find i) size of the spring wire ii) spring coil diameter iii) number of
spring-turns and iv) free length. The compression of the spring at maximum load is
30 mm and the rigidity modulus G is 80 kN/mm’. Take Wahl’s curvature effect into
consideration. Assume the end conditions as squared and ground.
Design and draw a rigid flange coupling to transmit 18 kW at 1440 rpm. The
allowable shear stress for CI flange is 4 MPa. The shafts, keys and bolts are made of
annealed steel having allowable shear stress of 93 MPa. Allowable crushing stress for
key is 186 MPa. Assume a key way factor of 75%.
What are the methods to equalize the stresses in all leaves (full length and graduated)
in a semi-elliptical leaf spring?
A hollow shaft is supported by two bearings A and B placed at 1.2 m apart. A 600
mm diameter pulley B is mounted at a distance of 200 mm to the right of left hand
bearing and this drives a pulley directly below it with the help of a belt having
maximum tension of 2 kN. Another pulley C of 400 mm diameter is placed 200 mm
to the left of the left hand bearing and is driven with the help of a motor and belt
which is placed at 45° to vertical and downward towards the observer. The angle of
contact for both pulleys is 180° and coefficient of friction is 0.25. Determine the
suitable diameter for hollow shaft having diameters ratio of 0.5. The allowable tensile
and shear stresses are 63 MPa and 42 MPa respectively. Take shock factors for

bending and twisting as 2.5 and 2.0 respectively.

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