21ME63

Model Question Paper-1 with effect from 2022-23 (CBCS Scheme)

USN

6th Semester B.E. Degree Examination

Machine Design (21ME63)
TIME: 03 Hours Max.Marks:100

Note: 01.Answer any FIVE full questions, choosing at least ONE question from each MODULE.
02. Use of Machine Design Data Hand Book is permitted.
03. Missing data may be suitably assumed.

*Bloom’s
Module-1 Taxonomy Marks
Level
Q.01 a Enumerate important mechanical properties of engineering materials L1 4
b A steel saw blade 1 mm thick is bent into an arc of a circle of 500 mm
radius. Determine the flexural stress induced and bending moment L3 8
required to bend the blade, which is 15mm wide. Take E= 210 GPa.
c A 50 mm diameter steel rod
supports a 9.0 kN load and in
addition is subjected to a torsional
moment of 100 N-m as shown in L3 8
Fig.1(c). Determine the maximum
tensile and the maximum shear
Fig 1(c)
stress.
OR
Q.02 a A notched flat plate shown in Fig
2(a) is subjected to bending
moment of 10 N-m. Determine the
L3 7
maximum stress induced in the
member by taking the stress Fig 2(a)
concentration into account.
b Derive an expression for instantaneous stress due to axial impact L2 6
c A cantilever beam made of cold
drawn carbon steel (σu = 550 MPa,
σy = 470 MPa, σ-1 = 275 MPa) of
circular cross-section shown in Fig
2(c) is subjected to load which L3 7
varies from –F to 3F. Determine the
maximum load that the cantilever
Fig. 2 (c)
can withstand for an infinite life,
using a factor of safety of 2.

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Module-2
Q.03 a Design the shaft of the armature of a motor, if the magnetic pull on the
shaft is equivalent to a uniformly distributed load of 10N per mm length
over the middle one third of the 600 mm length of the shaft between L3 16
bearings. The motor transmits a power of 15 kW at 1200 rpm. The
allowable shear stress is 50 MPa. Take Cm = 1.5 and Ct = 1.25.
b Mention the design steps for flange coupling L1 4
OR
Q.04 a Design a Flange Coupling to connect the shafts of a motor and
centrifugal pump for the following specifications: Pump output = 3000
liters/minute; Total head = 20 m; Pump speed = 600 rpm; Pump
L3 16
efficiency = 70 %. Select C40 steel (σy = 328.6 MPa) for shaft and C35
steel (σy = 304 MPa) for bolts with factor of safety 2. Use allowable
shear stress in cast iron flanges equal to 15 N/mm2 .
b What are the types of springs?
L1 4
Module-3
Q.05 a A double riveted lap joint is to be made between 9 mm plates. If the safe
working stresses in tension, crushing and shear are 80 N/mm2 and 60 L3 12
N/mm2 respectively, design the riveted joint.
b A riveted bracket is supported by
means of four rivets of same size as
shown in Fig. Q5 (b). Determine
L3 8
the diameter of the rivet if the
maximum shear stress in the rivet is Fig Q 5(b)
90 N/mm2.
OR
Q.06 a A plate of 80 mm wide and 10 mm thick is to be welded to another plate
by means of two parallel fillet welds. The plates are subjected to a load
of 50 kN. Find the length of weld so that maximum stress does not L3 10
exceed 50 N/mm2. Consider the joint under static loading and then
under dynamic loading.
b A 16 mm thick plate is welded to a
vertical support by two fillet welds
as shown in Fig. 6 (b). Determine
the size of weld, if the permissible L3 10
shear stress for the weld material is
75 MPa.

Fig. Q 6 (b)
Module-4
Q.07 A pair of carefully cut spur gears with 20° full depth involute profile is
used to transmit 12 kW at 1200 revolutions per minute of pinion. The
gear has to rotate at 300 revolutions per minute. The material used for L3 20
both pinion and gear is medium carbon steel whose allowable bending
stress may be taken as 230 MPa. Determine the module and face width

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 21ME63
of the spur pinion and gear. Suggest suitable hardness. Take 24 teeth
on pinion. Modulus of elasticity may be taken as 210 GPa.
OR
Q.08 Design a pair of helical gears to transmit a power of 20kW from a shaft
running at 1500 rpm to a parallel shaft to be run at 450 rpm. Suggest L3 20
suitable hardness for the gear pair.
Module-5
Q.09 a Design a single plate clutch consists of two pairs of contacting surfaces
for a torque capacity of 200 Nm. Due to space limitations the outside L3 10
diameter of the clutch is to be 250 mm.
b A simple band brake of drum diameter 600 mm has a band passing
over it with a angle of contact of 225°, while one end is connected to
the fulcrum, the other end is connected to the brake lever at a distance
of 400mm from the fulcrum. The brake lever is 1 m long. The brake is L3 10
to absorb a power of 15 kW at 720 rpm. Design the brake lever of
rectangular cross-section, assuming depth to be trice the width. Take
allowable stress 80 MPa.
OR
Q.10 a Write short note on Hydrodynamic Theory of lubrication, showing
L2 10
pressure distribution and a graph of friction v/s speed.
b Explain the types of rolling contact bearings and their applications L2 10

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 21ME63
Model Question Paper-2 with effect from 2022-23 (CBCS Scheme)
USN

Sixth Semester B.E. Degree Examination

MACHINE DESIGN
TIME: 03 Hours Max. Marks: 100
Note: 01.Answer any FIVE full questions, choosing at least ONE question from each MODULE.
02. M: Marks, L: Blooms Level, C: Course outcomes
03. Use of Design Data Hand Book is permitted.
04. Assume missing data suitably

Module-1 M L C

Q.01 a Describe six-step process of design with a flow chart. 5 L2 CO1

b Describe briefly with a neat sketch Stress-Strain diagram considering an
5 L2
example for Ductile and Brittle Material. CO1
c A shaft of 50 mm diameter is subjected to a tensile load of 10kN, bending load
of 3kN and a torque of 3kN-m as shown in figure Q1(c), determine the stresses
at points A and B.

A
10 L3 CO1

Figure Q 1(c)
OR
Q.02 a Determine the thickness of a flat plate loaded as shown in figure Q2(a)
limiting the maximum stress induced in the material to 80 Mpa.

10 L3 CO1

Figure Q 2(a)

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 21ME63
b Derive an equation for Impact stress induced in a member subjected to axial impact
loading. 10 L3 CO1
Module-2
Q.03 a A shaft is supported by two bearings placed 1100mm apart. A pulley of
diameter 620mm is keyed at 400mm to the right from the left hand bearing
and this drives the pulley directly below it with maximum tension of 2.75 kN.
Another pulley of diameter 400mm is placed 200mm to the left of right 20 L3 CO2
bearing and is driven with a motor placed horizontally to the right. The angle
of contact of pulley is 1800 and μ= 0.3. Find the diameter of the shaft. Take
Cm=0.3, Ct=2.5, σy= 190 MPa and σut= 300 MPa
OR
Q.04 a Design a flexible flanged coupling to transmit a power of 25kW at speed of
500rpm. Assume Shaft, Keys, Pins are made of C40 steel with FOS=2 and 10 L3 CO2
flanges are made of Cast iron with FOS=6. Assume bearing pressure=0.5Mpa.
b Derive an expression for stresses and deflection induced in a helical spring,
10 L3 CO2
with usual notations.
Module-3
Q.05 a Explain Caulking and Fullering with a neat sketch. 5 L2 CO3
b Explain in brief, the types of failures in riveted joints. 5 L2 CO3
c Design a double riveted lap joint to connect two plates each 20mm thick. The
allowable stress for rivets and plates are 90MPa in tension, 60MPa in shear 10 L3 CO3
and 150MPa in crushing.
OR
Q.06 a A 125 X 100 X 10mm unequal leg angle section is to be welded to a steel plate
by fillet welds along the edges of the 125mm legs as shown in Fig. Q6(a). The
angle is subjected to a tensile load of 100kN passing through the center of
gravity of angle. Determine the weld length if the size of the weld in 8mm and
the allowable shear stress in the weld is 102MPa. All dimensions in the figure
are in mm.

10 L3 CO3

Fig Q6(a)
b The cylinder head of a steam engine is subjected to a steam pressure of
0.7N/mm2 It is held in position by means of 12 bolts. A soft copper gasket is
used to make the joint leak proof. The effective diameter of the cylinder is 10 L3 CO3
300mm. Find the size of the bolt so that the stress in the bolt is not to exceed
100N/mm2
Module - 4
Q. 07 a Derive Lewis beam strength equation for a spur gear tooth. 5 L3 CO4
b Design a pair of spur gear to transmit 20kW power from a shaft rotating at 15 L3 CO4
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1000rpm to a parallel which is to rotate at 310rpm. Assume number of teeth on
pinion as 31 and 20o full depth tooth form. The material of the pinion is
C45steel untreated and for gear cast steel 0.20%C untreated.
OR
Q.08 Design a pair of bevel gears to connect two shafts at 120 degree and to
transmit 6kW at 1200 rpm of the pinion. The driven shaft is to rotate at 20 L3 CO4
800rpm. The design should be as compact a possible.
Module - 5
Q. 09 a Design a single plate clutch to transmit 30kW at 1200rpm. The outside
diameter of friction lining is 1.5 times the inside diameter. It is lined with 10 L3 CO5
asbestos having allowable pressure of 0.24MPa and coefficient friction of 0.3
b A cast iron fly wheel rotating at 600rpm is brought to rest by a break in 2sec.
The flywheel may be considered as a solid circular disc having a diameter of
400mm and thickness 100mm. The density of cast iron is 7200 kg/m3.
Determine: 10 L3 CO5
i. Energy absorbed by the brake
ii. Number of turns drum rotates before coming to rest
iii. The Braking Torque
OR
Q. 10 a Derive an expression for Petroff’s equation for coefficient of friction. 10 L3 CO5
b A journal bearing of 100mm in diameter and 100mm in long supports a load
of 50KN at 1400rpm. The radial clearance is 0.12mm and the absolute
viscosity of the oil is 16CP. Determine:
i) Co-efficient of friction. 10 L3 CO5
ii) Power loss due to friction
iii) Minimum oil film thickness
iv) Flow rate of lubricant.

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