COIMBATORE INSTITUTE OF TECHNOLOGY
(Autonomous Institution Affiliated to Anna University)
DEPARTMENT OF MECHANICAL ENGINEERING
MID-SEMESTER EXAMINATION- I
Program: III Semester - PTBE Mechanical Engineering (2024-2025)
23PM312 STRENGTH OF MATERIALS
CouliFasfructor: Mr. K.Kartlnk
Date of Examination: 28.08.2024
Time: 6:00 p.m. - 8:30 p.m. Max. Marks: 60
COURSE OUTCOMES
At the end of the course, the students will be able to
C01: Analyze the deformation and the state of internal effects caused by external loads acting on bodies
CO2: Determine and Draw shear force and bending moment diagrams of simple beams subjected to various
loading conditions.
CO3: Calculate slope and deflection in beams using different methods
C04: Apply basic equation of torsion in designing of shafts and helical springs
C05: Analyze thin and thick cylinders, shells for applied pressures and columns with different end conditions
PART A ( 6 x 2 = 12)
Answer all the Questions.
S.No
Questions CO BT
1. Draw the stress strain curve for a brittle material and mark the various points in the
1 LI
curve.
2. Define Poisson's ratio., 1 L1
s
3. Write the formula that relates the modulus of elasticity and modulus of rigidity. 1 Li
4. Giva a short note on volumetric strain. 1 L1
5. WI-Tat is principal plane and principal stress? 1 L1
6 A tensile load of 60 kN is gradually applied to a circular bar of 4 cm diameter and 5m
1 L1
long. If the value of E=2x105 N/mm2 determine the strain energy absorbed by the rod.
PART B ( 4 x 12 = 48 )
Answer any 4 Questions from Q.No 11 to 15
11 A member ABCD is subjected to point loads P1, P2, P3 and P4 as shown in figure.
Calculate the force P2 necessary for equilibrium, if P1 = 45 kN, P3 = 450 kN and P4 = 130
kN, and determine the total elongation of the member. Assuming the modulus of elasticity
as 2.1 x 105 N/mm2.
12 Three pillars, two of aluminium and one of steel support a rigid platform of 250 kN as
shown in Figure. If area of each aluminium pillar is 1200 mm2 and that of steel pillar is
1000 mm2, find the stresses developed in each pillar. Take Es = 2 x 105 N/mm2 and Ea = 1
x 106 N/mm2.
13 A rectangular block of material is subjected to a tensile stress of 110 N/mm2 on one
plane and a tensile stress of 47 N/mm2 on the plane right angle to the former. Each of
the above stresses is accompanied by a shear stress of 63 N/mm2 and that associated
with the former tensile stress tends to rotate the block anticlockwise. Find (i) the
direstion and magnitude of the principal stresses, (ii) magnitude of the greater shear
stress.
14 Calculate the modulus of rigidity and bulk modulus of a cylindrical bar of diameter 30
mm and of length -1.5m if the longitudinal strain in a bar during a tensile stress is tour
times the lateral strain. Find the change in volume, when the bar is subjected to a
hydrostatic pressure of 100 N/mm2. Take E=1x105 N/mm2
15 A point in a strained material is subjected to stresses as shown in diagram using Mohr's
circle method, determine the normal and tangential stresses across the oblique plane.
Check the answer analytically.
nr ry
COIMBATORE INSTITUTE OF TECHNOLOGY
(Autonomous Institution Affiliated to Anna University)
DEPARTMENT OF MECHANICAL ENGINEERING
MID-SEMESTER EXAMINATION- II
Program: III Semester - PTBE Mechanical Engineering (2024-2025)
2311M312 STRENGTH OF MATERIALS
Course Instructor: Mr. K.Karthik
Date of Examination: 05.11.2024
Time: 6:00 p.m. - 8:30 p.m. Max. Marks: 60
COURSE OUTCOMES
At the end of the course, the students will be able to
COL Analyze the deformation and the state of internal effects caused by external loads acting on bodies
CO2: Determine and Draw shear force and bending moment diagrams of simple beams subjected to various
loading conditions.
CO3: Calculate slope and deflection in beams using different methods
C04: Apply basic equation of torsion in designing of shafts and helical springs
C05: Analyze thin and thick cylinders, shells for applied pressures and columns with different end conditions
Part — A (10 x 2 = 20)
CO BTL
1.' List the assumptions made in the theory of simple bending CO3 L1
2. Define Section Modulus CO3 L2
3. Define point of contra flexure? In which beam it occurs? CO3 L2
4. Define point of contra flexure? In which beam it occurs? CO3 L2
5. In a simply supported beam how will you locate point of maximum bending CO4 L3
moment?
6. What are the types of loads? C04 L1
7. Define polar modulus C04 L2
8. Why hollow circular shafts are preferred when compared to solid circular C04 L3
shafts?
9. Define thin cylinder? C05 L2
10. What are types of stress in a thin cylindrical vessel subjected to internal CO5 Ll
pressure?
PART — B Answer any Four (10 x 4 = 40)
11 The tension flange of a cast iron I-section beam is 240 mm wide and 50 10 CO2 L3
mm deep, the compression flange is 100 mm and 20 mm deep
whereas the web is 300 mm x 30 mm. Find the load per m run which
can be carried over a 4 m span by a simply supported beam if the
maximum permissible stresses are 90 MPa in compression and 24 MPa
in tension.
12 Compare the flexural strength of three beams of equal weight with the 10 CO3 L3
following specifications:
(i) 1-section with length of web thickness of each flange and the
thickness of web in terms of width b of the flanges being
1.7b, 0.15b and 0.1 b respectively.
(ii) Rectangular section of depth equal to twice the width
(iii) Solid circular section
13 The horizontal shaft AD is attached to a fixed base at D and is 10 C04 L3
subjected to the torques shown. A 44-mm-diameter hole has been
drilled into portion CD of the shaft. Knowing that the entire shaft is
made of steel for which G = 77 GPa, Determine the angle of twist at end
A.
14.A simply supported beam of 7 m span with overhangs rests on
supports which are 4 rri apart. The left end overhanging is 2 m. The
beam carries loads of 30 kN and 20 kN on the left and right ends
respectively apart from the uniformly distributed load od 25 kN/m
between the supporting points. Draw the shear force and bending
moment diagrams.
15 A 10 m long simply supported beam carries a point load of 4 kN at 8 m 10 C04 L3
from the left end along with uniformly distributed load of 4 kN/m
intensity for 3 m length starting from the left end. The beam is also
acted upon by a clockwise couple of 10 kN.m at mid point of the span.
Draw the shear force and bending moment diagram
16 A 600 mm long steel cylinder is made up of 4 mm thick plates. The 10 C04 L3
inside diameter of the cylinder is 120 mm. when it is subjected to an
internal pressure of 5 MPa, the increase in its volume is found to be
5000 mm3. Determine the value of poisons ratio and the modulus of
rigidity. Take E = 205 GPa
Page 2 of 2
NIA/2024 23PM312
Reg. No. 9 305.717 1(1-s2to3--g
(To be filled by the candidate) (2023 Batch)
COIMBATORE INSTITUTE OF TECHNOLOGY
(Government Aided Autonomous Institution)
COIMBATORE 641 014
PART TIME B.E. DEGREE EXAMINATIONS, NOVEMBER 2024
(Third Semester)
MECHANICAL ENGINEERING BRANCH
23PM312 STRENGTH OF MATERIALS
Time : 3 Hours Max: 100 Marks
INSTRUCTIONS
1. Answer all questions in Part A and as per choice in PART B.
2. Part A and Part B questions should be answered
separately in the same answer sheet.
PART - A
(10 X 2 = 20)
M BTL CO
1. Given an example for gradually applied load and suddenly applied load. 2 L1 CO1
2. What is resilience? 2 L2 CO1
3. State the two conditions employed in solving a composite bar subjected to an 2 Ll C01
axial load.
4. List the different types of supports used in beams. 2 L2 CO2
5. State the theory of simple bending. 2 L1 CO3
6. Why hollow circular shafts are preferred when compared to solid circular 2 L2 CO4
shafts?
7. Write the maximum value of deflection for a simply supported beam of a length 2 L1 CO3
L, constant El and carrying a central concentrated load W.
8. Define the term slope. 2 L1 CO3
9. Distinguish between thin walled cylinder and thick walled cylinder? 2 L2 CO5
10. What is effective length of column? 2 L2 C05
PART — B
(5x 16 = 80)
11. A composite rod is 1000 mm long, its two ends are 40 mm2 and 30 mm2 in area 16 L3 C01
and length are 300 mm and 200 mm respectively. The middle portion of the rod is
20 mm2 in area and 500 mm long. If the rod is subjected to an axial tensile load
of 1000 N, find its total elongation and stresses in each portion. (E = 200 GPa).
Contd...
12 A rod consists of two parts that are made of steel and copper as shown in figure 16 L3 CO1
below. The elastic modulus and coefficient of thermal expansion for steel are
200 GPa and 11 7 x 10-6 per °C respectively and for copper 70 GPa and 21.6 x
10-6 per °C respectively. If the temperature of the rod is raised by 50°C
determine the forces and stresses acting on the rod.
13 A bar of 20 mm diameter is tested in tension. it is observed that when a load of 16 L3 CO2
37.7 kN is applied, the extension measured over a guage length of 200 mm is
0.12 mm and contraction in diameter is 0.0036 mm. find the poisons ratio and
elastic constants E, G and K.
(OR)
14 The direct stresses acting at a point in a strained material are as shown in 16 L4 CO2
diagram. Find the normal, tangential and the resultant stresses on a plane of
30° to the plane of major principle stress. Find the obliquity of the resultant
stress also.
15 Draw the shear force and bending moment diagram for the beam shown in 16 L3 CO3
figure.
16 A girder 6 m long rests on two supports with equal overhangs on either side 16 L3 CO3
and carries a uniformly distributed load of 30 kN per metre run over the entire
length. Calculate the overhangs if the maximum bending moment, positive or
negative, is to be as small as possible. Draw SFD and BMD diagrams for the
double overhang beam.
17 Obtain an expression
for the deflection curve of the simply supported beam, 16 • 3 CO4
subject to the uniformly distributed load w throughout the length.
(OR)
18 The tension flange of a cast iron i-section beam is 100 mm wide and 20 mm 16 L3 C04
deep, the compression flange is 50 mm wide and 20 mm deep whereas the
web is 100 mm x 20 mm. if a similar I-section is welded on the top of it to form a
symmetrical section, find the ratio of the moment of resistance of this section to
that of the previous section assuming the allowable stress in tension and
compression to be the same.
1
1 9.A shaft transmits 280 kW of power at 160 rpm. Determine 16 L3 C05
(i) The diameter of a solid shaft to transmit the required power
(ii) The inner and outer diameters of a hollow circular shaft if the ratio of
the inner to the outer diameter is 213
(iii) The percentage saving in the material on
using a hollow shaft
instead of a solid shaft
Take the allowable stress as 80 MPa and the density of material 78 kN/m3
(OR)
20 Wall thickness of a cylindrical shell of 800 mm internal diameter and 2 m long is 16 L3 C05
10 mm. If the shell is subjected to an internal pressure of 1.5 MPa, find the
following:
(i) The maximum intensity of shear stress induced
(ii) The change in dimensions of the shell
Take E = 205 GPa and v= 0.3
*****A********
