Reg No.:

00000ME401121903

Pages: 3

Name:

APJ ABDUL KALAM TECHNOLOGICAL UNIVERSITY

Seventh Semester B.Tech Degree Examination (Regular and Supplementary), December 2020

Max. Marks: 100

1 a)
b)
௦)
2 a)
b)
3 ஐ
b)
4 ஐ

Course Code: ME401
Course Name: DESIGN OF MACHINE ELEMENTS - I

Use of Design Data Book is permitted
Missing data if any may be suitably assumed
PARTA
Answer any two full questions, each carries 15 marks.
Explain the BIS system for designation of steels based on its composition?
Define stress concentration. Give any three methods to reduce stress
concentration caused by a notch on a flat plate.
A steel column having square cross section of 90 mm side carries a load of 120
KN at an eccentricity of 12 mm in a plane bisecting the thickness. Find the
maximum and minimum intensities of stress in the section.
Taking stress concentration into account find the maximum stress induced in a
shaft when a tensile load of 15 KN is applied to a stepped shaft of diameters 50
mm and 20 mm with a fillet of radius of 5 mm.
A steel shaft is subjected to the following loads: the bending moment varying
from -150 Nm to +400 Nm; The twisting moment varying from 70 Nm to 200
Nm and the axial force varying from -50 N to 150 N. Determine the dimension
of the shaft using Von Mises Hencky theory. The frequency of variation of the
loads is same as the shaft speed. The properties of the material of the shaft are
yield strength = 400 MPa, endurance strength = 310 MPa, ultimate strength =
620 MPa. Take ‏کا‎ = 1.85, Notch sensitivity factor (व) = 0.95, K ०= 0.75, K ‏حم‎
‎0.85, K 5 0.9 and Factor of Safety (n) = 2.
Explain how the strength and stiffness factors of machine elements affect the
design.
The bending stress in a machine part fluctuates between a tensile stress of
300MPa and compressive stress of 160 MPa. What should be the minimum
ultimate tensile strength of this part to carry this fluctuation indefinitely
according to (i) Goodman’s formula (b) Soderberg relation and (c) Gerber
relation? Take the yield point as 60% of ultimate tensile strength and Endurance
limit as 50% of ultimate tensile strength and Factor of safety as 2.
PART 13
Answer any two full questions, each carries 15 marks.
A bolt M20 x 2.5 metric thread is subjected to a fluctuating load varying from
zero load (0 N) to 14 KN. Endurance strength = 210 MPa. Bolt and part are of
same material and length. Take ൭5480 MPa, Stress concentration factor= 3.85,

Page lof 3

Duration: 3 Hours

Marks

(2)

(7)

(6)

(3)

(12)

(3)

(12)

(12)