Download GTU (Gujarat Technological University) BE/BTech (Bachelor of Engineering / Bachelor of Technology) 2017 Winter 5th Sem Old 152503 Design Of Mc Elements I Previous Question Paper
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE ? SEMESTER ? V(OLD)- EXAMINATION ? WINTER 2017
Subject Code: 152503 Date:08/11/17
Subject Name: Design of M/c Elements - I
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define:
Stress concentration, Fatigue Failure, Endurance limit, Size factor, Notch
sensitivity, Surface finish factor.
07
(b) A cantilever beam of cold drawn steel 40C8 (Sut = 600 N/mm
2
and S yt = 380
N/mm
2
) is shown in fig below. The force P acting at the free end varies from -
50 N to +150 N. the expected reliability is 90% and the factor of safety is 2. The
notch sensitivity factor at the fillet is 0.9. Determine the diameter?d? of the beam
at the fillet cross section.
07
Q.2 (a) Explain: Single plate clutch, self locking block brake, Differential band brake 07
(b) The block type hand brake shown in fig. has a face width of 45 mm. The friction
Material permits a maximum pressure of 0.6 MPa and a coefficient of friction of
0.24. Determine;1. Effort F, 2. Maximum torque, 3. Heat generated if the speed
of the drum is 100 rpm and the brake is applied for 5 sec. at full capacity to bring
the shaft to stop.
07
OR
(b) A single plate friction clutch of both sides effective has 300 mm outer diameter
and 160 mm inner diameter. The coefficient of friction o.2 and it runs at 1000
rpm. Find the power transmitted for uniform wear and uniform pressure
distributions cases if allowable maximum pressure is 0.08 Mpa.
07
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1
Seat No.: ________ Enrolment No.___________
GUJARAT TECHNOLOGICAL UNIVERSITY
BE ? SEMESTER ? V(OLD)- EXAMINATION ? WINTER 2017
Subject Code: 152503 Date:08/11/17
Subject Name: Design of M/c Elements - I
Time: 10:30 AM TO 01:00 PM Total Marks: 70
Instructions:
1. Attempt all questions.
2. Make suitable assumptions wherever necessary.
3. Figures to the right indicate full marks.
Q.1 (a) Define:
Stress concentration, Fatigue Failure, Endurance limit, Size factor, Notch
sensitivity, Surface finish factor.
07
(b) A cantilever beam of cold drawn steel 40C8 (Sut = 600 N/mm
2
and S yt = 380
N/mm
2
) is shown in fig below. The force P acting at the free end varies from -
50 N to +150 N. the expected reliability is 90% and the factor of safety is 2. The
notch sensitivity factor at the fillet is 0.9. Determine the diameter?d? of the beam
at the fillet cross section.
07
Q.2 (a) Explain: Single plate clutch, self locking block brake, Differential band brake 07
(b) The block type hand brake shown in fig. has a face width of 45 mm. The friction
Material permits a maximum pressure of 0.6 MPa and a coefficient of friction of
0.24. Determine;1. Effort F, 2. Maximum torque, 3. Heat generated if the speed
of the drum is 100 rpm and the brake is applied for 5 sec. at full capacity to bring
the shaft to stop.
07
OR
(b) A single plate friction clutch of both sides effective has 300 mm outer diameter
and 160 mm inner diameter. The coefficient of friction o.2 and it runs at 1000
rpm. Find the power transmitted for uniform wear and uniform pressure
distributions cases if allowable maximum pressure is 0.08 Mpa.
07
2
Q.3
(a)
Explain function of flywheel along with the application. State why Flywheel are
used in Presses?
07
(b) It is required to select a V-Belt drive to connect a 15kW, 2880 rpm normal torque
A.C. motor to a centrifugal pump, running at approximately 2400 rpm, for a
service of 18 hours per day. The centre distance should be approximately 400
mm. Assume that the pitch diameter of the driving pulley is 125 mm. Take
correction factor according to service Fa = 1.2, Correction factor for belt pitch
length Fc = 0.87.Consider the cross section of V-belt is B. Pitch Length of belt
is 1210 mm. Power Rating of Single V-belt Pr = 4.46kW.
07
OR
Q.3 (a) Derive an expression of length of cross belt drive. 07
(b) Explain the basic difference between the Function of Flywheel and Governor. 07
Q.4 (a) Explain the design procedure of Piston rod. 07
(b) A pair of spur gears with 20
0
full depth involute teeth consist of a 20 teeth pinion
meshing with a 41 teeth gear. The module is 3 mm while the face width is 40
mm. The material for pinion as well as gear is steel with an ultimate tensile
strength of 600 N/mm
2
. The gears are heat treated to a surface hardness of 400
BHN. The pinion rotates at 1450 rpm and the service factor for the application is
1.75. Assume that velocity factor accounts for dynamic load and the factor of
safety is 1.5
Determine the rated power that the gears can transmit.
07
OR
Q.4 (a) Explain Johnson?s formula for Columns. Describe the use of Johnson?s formula
and Euler?s formula.
07
(b) A helical compression spring made of circular wire is subjected to an axial force,
which varies from 2.5 kN to 3.5 kN. Deflection is 5 mm. Spring index is 5. The
spring has round and square ends. The spring is made from material having
ultimate tensile strength of 1050 N/mm
2
and modulus of Rigidity 81370 N/mm
2
.
The permissible shear stress can be taken as 50% of ultimate tensile strength.
Calculate: wire diameter, mean coil diameter, number of active coils, total
number of coils, Solid and free length.
07
Q.5 (a) Name the methods used to design thick cylinder to withstand internal pressure
equal to or greater the allowable working stress.
Also show the stress distribution across the wall thickness due to shrinkage fitting
and internal fluid pressure.
07
(b) The piston rod of hydraulic cylinder exerts an operating force of 10 kN. The
friction due to piston packing and stuffing box is equivalent to 10% of operating
force. The pressure in the cylinder is 10 MPa. The cylinder is made of cast iron
FG200 and factor of safety is 5. Determine the diameter and thickness of the
cylinder.
07
OR
Q.5 (a) Define: through bolt, machine bolt, automobile bolt, tap bolt, stud 07
(b) Explain the terminology of Screw thread. 07
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This post was last modified on 20 February 2020