Download AKTU (Dr. A.P.J. Abdul Kalam Technical University (AKTU), formerly Uttar Pradesh Technical University (UPTU) B-Tech 5th Semester (Fifth Semester) 2015-2016 Machine Design I Nme 501 Question Paper
(Following Paper ID and Roll No. to be ?lled in your
' Answer Book)
Roll No.
B.Tech.
(SEM. V) THEORY EXAMINATION, 2015-16
MACHINE DESIGN-I
Time : 3 hours] ~[MalutimumMarks : 100
Note :Attempt all sections (A, B and C) -
Section-A
1. Attempt all parts. All sections carry equal marks. Write
answer of each section in short. (lOXZ=20)
(a) List the factors that in?uence the selection of
materials for speci?c application.
(b) What is ergonomic consideration in design?
(0) Why Wahl?s correction factor is used in spring
design?
( 1) P.T.O.
'(d)
(e)
(f)
(g)
(h)
(i)
0)
Why preferred numbers are important in machine
design?
Why fatigue failure of materials is important while
designing machine part?
Why ef?ciency of screw jack should not be more
than 50%?
Why most of the components lare designed for
in?nite life? '
Why repeated stresses are? crucial in ductile
materials?
List components designed for ?nite life.
What is rated life of a system?
Secti'on-B
Note: Attempt any ?ve questions from this section.
Q2- (3)
(b)
1 0 X 5 =5 0
What are preferred numbers in design?
A manufacturer is interested to start a business with
six models of machines ranging from 7.5 kW -75
kW. Specify power capacity of six models.
(2) NME-501
;
l
(a)
(b)
(a)
g 20 w
.0
?W3 O O;
(b) A cylindrical bar made of Fe620 is ssubjected to
What do you understand by i) FE320 ii) F eE 200
iii) 40C8.
How will you designate the following varieties of
steel i) carbon= 30-40%, Si=0.8-0.9%, Mn=0.7-
0.9%, Cr=3.5-4.5%. ii) C=45-55%, Cr=l8%,
Va=21%
A rectangular bar made of carbon steel 40C8 is
subjected to a tensile load as shown in ?g 1.0.
Calculate the max stress in the bar with ?llet radius
being 3mm (aal dimensions in mm).
combined bending moment and to torsional
moment of lOkN-m & 30kN-m respectively.
Determine the diameter of the bar for a factors of
safely of 2.0
, (3) P.T.O _
(a) A stepped shaft, stepped from 40 mm to 30 mm is
subjected to a torsional moment of 100 N?m. If
the stress concentration at ?llet is 2.3, what is the
max stress in the shaft?
(b) A machine components is subjected to a bending,
stress varying from 300 MPa to -150 MPa.
Calculate the minimum required ultimate strength,
if the factor of saftey is 1.5
(a) Differentiate between collar friction and thread
friction.
\
(b) Design a triple riveted butt joint for a boiler of
1 .2m inner diameter operating at a steam pressure
of 1.5mPa. ~
Desi gn a protected type ?ange coupling to transmit 13 5
kW @ 120 rpm. Assume 40C8 as material for all
components. Assume any missing data.
(4) . NME-SOI
A helical spring made of oil tempered carbon steel
subjected to varying load from 600N to lOOON. Design
the spring for a spring index of 6 and a factors of safety
of 1.5. The material of the spring may be selected as
music wire.
Design the screw of a screw jack to lift a load of 95 kN
through a height of 250 mm. verify the design using
principal stresses and buckling failure.
Section-C
Attempt any two questions from this section.
(2x15=30)
10. (a) Distinguish between shaft axle and spindle.
(b) Design a shaft to transmit 25 kW @ 200 rpm
carying a central load of 900 N and is simply
supported between bearings 1.0 m apart. Allowable
tensile and shear stresses for material are 56 & 42
MPa respectively.
(5) P.T.O.
ll.
12.
A hot rolled steel shaft is subj ected to a variable bending
moment of +440 Nm to -220 Nm and a torsional
moment of 330 Nm to 110 Nm. Shaft is of no varying
crOss-section. Determine the required shaft diameter.
If the material has ultimate tensile and yield strength of
550 N/mm?2 and 440 N/mm2 with a factor of safety of
1.5.
\
A cylindrical steel sha? of ultimate and yield strength
of 580 & 360 N/mm2 respectivvely-and a cylindrical'
corrected endurance strength of 200 N/mmz, is subj ected
to a combined bending & tdtsional moments -30 MPa
to 3-30 MPa and -15 MPa to +30MPa respectively.
Calculate the factors of safety.
(6) NME-SOI / 18900
This post was last modified on 29 January 2020