PTU Punjab Technical University B-Tech May 2019 Question Papers 5th Semester Automobile Engineering
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Roll No.
Total No. of Pages : 03
Total No. of Questions : 09
B.Tech(AE) (2011 Onwards) (Sem.?5)
DESIGN OF AUTOMOTIVE COMPONENTS
Subject Code : BTAE-504
M.Code : 70487
Time : 3 Hrs. Max. Marks : 60
INSTRUCTION TO CANDIDATES :
1.
SECTION-A is COMPULSORY consisting of TEN questions carrying T WO marks
each.
2.
SECTION-B contains FIVE questions carrying FIVE marks each and students
have to attempt any FOUR questions.
3.
SECTION-C contains T HREE questions carrying T EN marks each and students
have to attempt any T WO questions.
SECTION-A
1.
Explain briefly :
a) List the Name of theories of failure.
b) What is synthesis of design? List the various factors of synthesis of design.
c) Define stress concentration factor and what are the design faults that give rise to stress
concentration?
d) Differentiate the concept of self-energizing and self-locking brakes.
e) What is the advantage of graduating the leaves of a laminated leaf spring?
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f) What do you understand by endurance limit and proportionality limit? What is their
significance in design of components?
g) List the name of various piston rings with their functions.
h) Which theory is used for design of clutch and why?
i) On what basis the material of flywheel is selected?
j) What is the basic concept behind the design of connecting rod and which formula is
used for its design?
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SECTION-B
2.
What are the factors to be considered for the selection of material for Crankshaft?
3.
What is meant by working stress and how it is calculated from the ultimate stress or yield
stress of a material? What will be the factor of safety in each case for different types of
loading?
4.
A circular steel bar 50 mm diameter and 200 mm long is welded perpendicularly to a steel
plate to form a cantilever to be loaded with 5 kN at the free end. Determine the size of the
weld, assuming the allowable stress in the weld as 100 MPa.
5.
A wall bracket, as shown in Fig. 1 is fixed to a wall by means of four bolts. Find the size of
the bolts and the width of bracket. The safe stress in tension for the bolt and bracket may be
assumed as 70 MPa.
600
40 kN
75
500
20
75
Fig.l.
6.
A centrifugal friction clutch has a driving member consisting of a spider carrying four
shoes which are kept from contact with the clutch case by means of flat springs until
increase of centrifugal force overcomes the resistance of the springs and the power is
transmitted by the frwww.FirstRanker.com
iction between the shoes and the case. Determine the necessary mass
and size of each shoe if 22.5 kW is to be transmitted at 750 r.p.m. with engagement
beginning at 75% of the running speed. The inside diameter of the drum is 300 mm and the
radial distance of the center of gravity of each shoe from the shaft axis is 125 mm. Assume
= 0.25.
SECTION-C
7.
Determine the size of a piston rod subjected to a total load of having cyclic fluctuations
from 15 kN in compression to 25 kN in tension. The endurance limit is 360 MPa and yield
strength is 400 MPa. Take impact factor = 1.25, factor of safety = 1.5, surface finish factor
= 0.88 and stress concentration factor = 2.25.
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8.
A cast iron flywheel is to be designed for a single cylinder double acting steam engine
which delivers 150 kW at 80 r.p.m. The maximum fluctuation of energy per revolution is
10%. The total fluctuation of the speed is 4 per cent of the mean speed. If the mean
diameter of the flywheel rim is 2.4 meters, determine the following :
(a) Cross-sectional dimensions of the rim, assuming that the hub and spokes provide 5% of
the rotational inertia of the wheel. The density of cast iron is 7200 kg/m3 and tensile
stress 16 MPa. Take width of rim equal to twice of thickness.
(b) Dimensions of hub and rectangular sunk key. The shear stress for the material of shaft
and key is 40 MPa.
(c) Cross-sectional dimensions of the elliptical arms assuming major axis as twice of minor
axis and number of arms equal to six.
9.
A pair of bevel gears connects two shafts at right angles and transmits 9 kW. Determine the
required module and gear diameters for the following specification :
Particulars
Pinion
Gear
Number of teeth
21
60
Material
Semi steel Grey
cast iron
Brinell hardness number
200
160
Allowable static stress
85 MPa
55 MPa
Speed
1200 r.p.m
420 r.p.m
Tooth profile
1
14 ? composite
1
14 ? composite
2
2
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NOTE : Disclosure of Identity by writing Mobile No. or Making of passing request on any
page of Answer Sheet will lead to UMC against the Student.
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This post was last modified on 04 November 2019