SOM.PDF

Prepared by,
M.SIVARAJ Lecturer / Mechanical /EPTC
DEPARTMENT OF MECHANICAL ENGINEERING
4020310-STRENGTH OF MATERIALS
IMPORTANT QUESTIONS – QUESTION BANK
UNIT-1 ENGINEERING MATERIALS
PART-A
1. Differentiate elasticity and plasticity.
2. Differentiate stiffness and toughness.
3. Differentiate between ductility and malleability.
4. What is meant by hardness? List out various hardness testing methods.
5. Define fatigue strength and endurance limit.
6. Describe the types of cast iron.
7. What is steel? Give its major classification.
8. What is hard steel? List out properties of hard steel.
9. List out various defects in steel.
10. What is HSS? Give its composition.
11. List out any four nonferrous metal and their uses.
12. What is the purpose of alloying?
13. What is proportionality limit and elastic limit?
14. What is the difference between Brinell and Vickers hardness testing
methods?
15. Differentiate Izod and Charpy test methods.
16. What is mean by force of friction and limiting force of friction.
17. Differentiate between static and dynamic friction.
18. What is mean by angle of friction?
19. What is mean by cone of friction?
20.Define coefficient of friction.
PART-B
1. List out the various mechanical properties of material. Explain any eight
properties.
2. List out the types of cast iron. Explain the effects of impurities in cast iron.

Prepared by,
3. List and explain the various types of steel.
4. Explain the effect of alloying elements on steel.
5. Explain in detail various market form of steel. List out its defects.
6. Explain the stress-strain diagram for mild steel specimen with its salient
points. (Tension test on ductile material in UTM)
7. List out the hardness testing method. Explain any two in detail.
8. Explain the various impact testing methods with neat sketch.
9. Explain the method of conducting fatigue test with neat sketch.
10. Explain the method of conducting creep test with neat sketch.
11. List out the various law of static and dynamic friction.
12. A specimen of steel 25 mm in diameter with a gauge length of 200 mm was
tested in a laboratory. The following data were referred.
Maximum load = 140 KN, load at yield point = 110 KN, load at fracture = 120
KN, the diameter at neck 12.5 mm and distance between gauge points after
fracture = 252 mm. Find the (i) yield stress (ii) Ultimate stress (iii) Nominal
stress at fracture (iv) Percentage elongation (v) percentage of reduction in
area.
UNIT-2 DEFORMATION OF METALS
PART-A
1. Define stress and strain.
2. States Hook’s Law.
3. Distinguish between linear and lateral strain.
4. Differentiate between Factor of safety and Load factor.
5. Define Poisson’s Ratio.
6. Define volumetric strain and Bulk modulus.
7. Define proof resilience and Modulus of resilience.
8. Define Young’s Modulus. Give its importance.
9. What is mean by working stress? Write down the formula for change in
length due to tensile load?
10. Define composite bar. State the conditions of composite bar.
11. Define temperature stress. Write its Formula.
12. Define Modulus of Rigidity.

Prepared by,
13. Define Strain energy or Resilience.
14. Write down the expression for the stress induced due to impact load and
suddenly applied load.
15. A mild steel rod of 25mm diameter and 200mm long is subjected to an axial
pull of 75KN. If the E = 2x105
N/mm2
, determine elongation of the bar.
16. A cement concrete cube of 150mm size crushes at a load of 300KN.
Determine the working stress. Take factor of safety is 3.
17. Find the strain energy that can be stored in a steel bar of 45mm in
diameter and 3m long subjected to a Pull of 105 KN. Take E = 200KN/mm2
.
The rod subjected to a gradually applied load.
18. Find the maximum stress and extension in bar 2m long and 25mm diameter
when it is subjected to a suddenly applied load of 50 KN. Take E =
200KN/mm2
.
PART-B
1. State and explain the three types of Elastic constants.
2. A circular bar of 20 mm diameter and 300 mm long is carries a tensile load of
30KN. Find the stress, strain and elongation of the bar. Take E=2x105
N/mm2
3. A steel bar of 20 mm wide,10mm thick and 2m long is subjected to a Pull of
20 KN along its length. Find the changes in dimensions and volume of the bar.
Take Young’s Modulus E= 2x105
N/mm2
and Poisson’s Ratio 1/m = 0.3.
4. A steel rod of 2m long 20 mm diameter is subjected to axial load of 45KN.
Find the change in diameter and change in volume of the rod. Take E =2x105
N/mm2
and m=3.
5. A circular bar of length 150mm diameter 50mm is subjected to an axial load
of 400KN. The extension in length and contraction in diameters are found to
be 0.25mm and 0.02 mm respectively after loading. Calculate the (i) Poisson’s
ratio (ii) Young’s Modulus (iii) Bulk Modulus and (iv) Rigidity Modulus.
6. A material has Young’s Modulus of 120 GPa and Rigidity Modulus of 50 GPa.
Find the value of Poisson’s Ratio and Bulk Modulus.

Prepared by,
7. A steel tube of 100 mm internal diameter and 12.5 mm thickness is surrounded
by Brass tube of same thickness such a way that the axes are coincide. The
compound tube is loaded by axial compression of 5 KN. Determine the load
carried by each tube and there is no buckling of tubes. Take Young’s modulus
for steel is 2x105
N/mm2
and that for Brass 1x105
N/mm2
. Tubes are in same
length.
8. Two vertical wire each 2.5mm diameter and 5m long jointly supported to a
weight of 2.5KN. one wire steel and another wire made up of different
material. If the wire stretches elastically by 6mm, find the load taken by each
wire and value E for second wire. Take Esteel = 2x105
N/mm2
.
9. A MS Bar 600 mm2
cross sectional area and 3 m long is rigidly fixed between
two plates at the ends, if the bar is heated through 80⁰C, obtain the stress
in the bar and reaction at the end plates when (i) The supports do not Yield
and (ii) The supports Yield by 10%. Take coefficient of linear expansion is
12x10-6
per⁰C and Young’s Modulus of Elasticity for material is 2x105
N/mm2
.
10. A steel specimen 150 mm2
in cross section stretched by 0.05mm over a 50 mm
gauge length under an axial load of 30KN. Find the strain energy stored in the
body at this stage, If the load at elastic limit of specimen is 50 KN. Calculate
the elongation at elastic limit and proof resilience of material.
11. Find the greatest weight that can be dropped from a height of 200mm onto a
collar on lower end of vertical bar 20mm diameter and 2.5 m long without
exceeding elastic limit stress of 300 N/mm2
. Also find the instantaneous
elongation. Take young’s Modulus is 2x105
N/mm2
.
12. A weight of 9.8 KN is dropped on to a collar at the lower end of a vertical bar
3m long 32mm diameter. Calculate the height of drop, if the maximum
instantaneous stress is not to exceed 240 n/mm2
. What is the corresponding
instantaneous elongation? (OR)
A weight of 1400 N is dropped on to a collar at the lower end of vertical bar
3m long and 25mm diameter. Calculate the height of drop, If the maximum
instantaneous stress produced is not to exceed 120 N/mm2
and take E = 2x105
N/mm2
.

Prepared by,
UNIT-3 GEOMETRIC PROERTIES OF SECTIONS AND THIN SHELLS
PART-A
1. Differentiate centre of gravity and centroid.
2. Define axis reference and axis of symmetry.
3. Define moment of inertia.
4. State parallel axis theorem.
5. State perpendicular axis theorem.
6. Define polar moment of inertia.
7. What is mean by radius of gyration.
8. State the moment of inertia of (i) rectangular and (ii) circular section about
its XX and YY axes.
9. What is mean by section modulus.
10. Distinguish between thin shell and thick shell.
11. State the nature of stresses induced in thin cylindrical shell.
12. Write down the expression for hoop stress and longitudinal stress induced in
the cylindrical shell.
13. Write down the formula for change in diameter and change in length of thin
cylinder.
14. A boiler 3m internal diameter is subjected to an internal pressure of 6 bar.
Find the hoop stress and longitudinal stress if the thickness of boiler plate is
12mm.
15. A boiler 2.8m internal diameter is subjected to a steam pressure of 0.8
N/mm2
. Find the hoop stress and longitudinal stress, if the thickness of boiler
plate is 10 mm.
16. Calculate the working pressure may be allowed in a boiler shell 1.8 m diameter
with plates 15mm thick. If the permissible stress in solid plate is not to exceed
70 N/mm2
.
17. A thin cylindrical shell of 1m diameter is subjected to an internal pressure of
1 N/mm2
. Find the suitable thickness of shell, if the ultimate tensile strength
of the plate is 400 N/mm2
. Take factor of safety as 4.

Prepared by,
18. A spherical vessel 3 m diameter is subjected to an internal pressure of 1.5
N/mm2
. find the thickness of the vessel required, if the maximum stress is
not to exceed 90 N/mm2
. Take the efficiency of the joint as 75%.
PART-B
1. An angle section of 100 mm wide and 120 mm deep has both the flanges are
10 mm thick. Determine the centroid of the section.
2. Find the centroid of an I section having top and bottom flange 200 x 40mm
and web is 160 x40mm.
3. The channel section of size 100 mm x 50 mm overall. The base as well as
flanges of channel are 15mm thick. Determine the centroid of the channel.
4. Find the centroid of an inverted T section with flange 150x 20mm and web is
100x25mm.
5. 5. Find the values of Ixx and Iyy of a T section 120mm wide and 120 mm deep
overall. Both the web and flange are 10 mm thick. Also find out its radius of
gyration about its axes.
6. A channel section of size 300mm and 100mm overall. The base as well as flange
of the channel are 10 mm thick. Calculate the moment of inertia about its
centroidal axes.
7. Find the moment of inertia about the centroidal axes XX and YY of an angle
section of size 90mm x75mm x20mm. Also calculate its radius gyration.
8. An I section has the top flange 100mmx 15mm, web is 150mm x20mm and the
bottom flange 180mmx 30 mm. calculate the moment of inertia Ixx and Iyy.
9. A long steel tube 70 mm internal diameter and wall thickness 2.5 mm has
closed ends and is subjected to an internal pressure of 10 N/mm2
. Calculate
the magnitude of hoop and longitudinal stress set up in the tube. If the
efficiency of the longitudinal joint is 80% which stress is affected and what
is its revised value?
10. A cylindrical shell 3 m long 500mm in diameter is made up of 20 mm thick
plate. If the cylinder is subjected to an internal pressure of 5 N/mm2
, find
the resulting hoop and longitudinal stress, change in diameter, change in length
and change in volume. Take Poisson’s Ratio as 0.3 and E = 2x105
N/mm2
.

Prepared by,
11. Calculate the increase in volume of a boiler 3m long and 1.5 m diameter, when
subjected to an internal tensile stress is not to exceed 30N/mm2
. Take
Poisson’s Ratio as 0.28 and E = 2.1x105
N/mm2
.
12. A spherical shell of 1m internal diameter and 5 mm thick is filled with fluid
until its volume increases by 0.2x106
mm3
. Calculate the pressure exerted by
the fluid on the shell. Take Poisson’s Ratio as 0.3 and E = 2x105
N/mm2
.
13. Calculate the depth to which a spherical float 200 mm diameter and 6 mm
thickness has to be immersed in water in order that its diameter is decreased
by 0.05 mm. Assume Poisson’s Ratio as 0.25 and E = 2x105
N/mm2
and specific
weight of water is 9810 N/m3
.
UNIT- 4 THEORY OF TORSION AMD SPRINGS
PART-A
1. What is mean by pure torsion?
2. Write down the assumption made in theory of pure torsion.
3. Write down the Torsion Equation.
4. Define Polar modulus. State the formula for solid and hollow shafts.
5. Define torsional strength and torsional rigidity.
6. List out the advantages of hollow shaft over solid shaft.
7. Draw the stress distribution for hollow and solid circular shaft.
8. What are the types of spring? Give its uses.
9. What are the laminated or leaf spring? Give its applications.
10. Compare open coil and closely coiled helical spring.
11. State the application of springs.
12. Define stiffness or spring constant. Also write its formula.
13. State the expression for deflection in closely coil helical spring.
14. Calculate the power transmitted by a solid shaft 100 mm diameter running at
250 rpm, if the shear stress in the shaft material is not exceed 75 N/mm2
.

Prepared by,
15. A hollow shaft of external and internal diameters as 100 mm and 40 mm is
transmitting power at 120 rpm. Find the power the shaft can be transmit, if
the shear stress is not to exceed 50 N/mm2
.
16. A closely coiled helical spring of alloy steel wire of 10 mm diameter having 15
complete turns with the mean coil diameter as 100 mm. calculate the stiffness
of the spring. Take C = 90x103
N/mm2
.
17. A closely coiled helical spring made of 12mm steel wire having 12 turns of mean
radius 60 mm elongates by 15mm under a load. Find the magnitude of load if
modulus of rigidity is given as 7.5x104
N/mm2
.
PART-B
1. A hollow circular shaft of 25 mm outside diameter and 20 mm inside diameter
is subjected to a torque of 50 N.m. find the shear stress induced at outside
and inside layer of the shaft.
2. A solid circular shaft has to transmit a power of 40 KW at 120 rpm. The
permissible shear stress is 100 N/mm2
. Determine the diameter of shaft, if
the maximum torque exceeds the mean torque by 25%.
3. Find the torque transmitted by (i) solid shaft of diameter 0.4 m (ii) hollow
shaft of external diameter 0.4 m and internal diameter 0.2 m, if the angle of
twist is not to exceed 1⁰ in a length of 10 m. Take C = 0.8x105
N/mm2
.
4. A solid shaft 20 mm diameter is transmitting 10 KW at 1200 rpm. Calculate
the maximum intensity of shear stress induced and the angle of twist in a
degree in a length of 1 m, if the modulus of rigidity for material is 8x104
N/mm2
.
5. A solid shaft is transmitting 100 KW at 180 rpm. If the allowable shear stress
is 60 N/mm2
, find the necessary diameter for the shaft. The shaft is not twist
more than 1⁰ in a length of 3 m. Take C = 80KN/mm2
.
6. A hollow shaft having inner diameter is 0.6 times the outer diameter is to be
replaced by a solid shaft of the same material to transmit 550 KW at
220rpm.The permissible shear stress is 80 N/mm2
. Calculate the diameters of
the hollow and solid shafts. Also calculate the percentage of saving in material.

Prepared by,
7. A closely coil helical spring made of steel wire of 10 mm diameter has 10 coils
of 120 mm mean diameter. Calculate the deflection of the spring under an axial
load of 100 N and the stiffness of spring.
8. The mean diameter of closely coiled helical spring is 5 times the diameter of
wire. It elongates 8 mm under an axial pull of 120N. if the permissible shear
stress is 40 N/mm2
, find the size of wire and number of coils in the spring.
Take C = 0.8x105
N/mm2
.
9. Design a closely coiled helical spring of stiffness 20 N/mm. the maximum
shear stress in the spring material is not to exceed 80 N/mm2
under a load of
600 N. the diameter of coil is to be 10 times the diameter of wire.
Take C = 85x103
N/mm2
.
10. A weight of 150 N is dropped on to a compression spring with 10 coils of 12
mm diameter closely coiled to mean diameter of 150 mm. if the instantaneous
contraction is 140 mm, calculate the height of drop. Take C = 0.8x105
N/mm2
.
11. A truck weighing 20 KN and moving at 6 Km/Hr has to be brought to rest by
a buffer. Find how many springs each of 15 coils will be required to store the
energy of motion during compression of 200 mm. the spring id made out of 25
mm diameter steel rod coiled to a mean diameter of 200 mm. Take C =
0.945x105
N/mm2
.
UNIT -5 SF AND BM DIAGRAMS OF BEAMS AND THEORY OF BENDING
PART – A
1. Define beam. List out the types of beam with neat sketches.
2. List out the various types of load acting on the beam.
3. What is UDL and UVL?
4. Define shear force and bending moment.
5. Draw the sign convention of shear force and bending moment.
6. Differentiate sagging and hogging moment.
7. Write the relation between load, shear force and bending moment.
8. What is mean by point of contraflexure?
9. Draw the SFD and BMD for simply supported beam with UDL.
10. Define simple bending or pure bending.
11. Write down the assumption made in theory of simple bending.

Prepared by,
12. Define neutral axis.
13. Write down bending equation or flexural formula.
14. Define section modulus of beam.
15. What is mean by moment of resistance?
16. A cantilever 4m long carries a udl of 30KN/m over half of its length adjoining
the free end. Draw SFD and BMD.
17. A cantilever 2m long carries a point load of 3 KN at its free end and another
point load of 2KN at a distance of 0.5 m from free end. Draw the shear force
and bending moment diagrams.
18. A steel wire of 5 mm diameter bent into circular shape of 5 m radius.
Determine the maximum shear stress induced in the wire. Take E= 2x 105
N/mm2
.
19. A simply supported beam is 300 mm wide and 400 mm deep. Determine the
stress at 40 mm above N.A, if the maximum bending stress is 15 N/mm2
.
PART-B
1. A cantilever 4m span carries a UDL of 10 KN/m for a length of 2.5m from the
fixed end and two point loads of 20KN and 30KN at the free end and at 1.5m
from the free end respectively. Draw SFD and BMD.
2. A cantilever of 2m long carries a point load of 20 KN at 0.8 m from the fixed
end and another point load of 5 KN at the free end. In addition, UDL of 15KN/m
is spread over the entire length of cantilever. Draw the SFD and BMD.
3. A simply supported beam of effective span 6m carries three point loads of
30KN,25KN and 40KN at 1m,3m and 4.5m respectively from the left support.
Draw SF and BM diagrams.
4. A simply supported beam of length 6m carries a UDL of 20KN/m throughout its
length and a point load of 30Kn at 2m from the right support. Draw the shear
force and bending moment diagrams.
5. A simply supported beam of span 10 m carries a udl of 20 KN/m over the left
half of the span and point load of30KN at the mid span. Draw the SFD and BMD.

Prepared by,
6. A simply supported beam AB of 8m length carries a udl of 5KN/m for a distance
of 4m from the left support A. The rest of the beam of 4m carries an udl of
10KN/m. draw SFD and BMD.
7. A rectangular beam 200 mm deep and 100 mm wide is simply supported over a
span of 8 m carries a central point load of 25KN. Determine the maximum stress
in the beam. Also calculate the value of longitudinal fibre stress at a distance
of 25mm from the top surface of the beam.
8. A simply supported beam of rectangular section carries a central point load of
25KN over a span of 6m. the bending stress should not exceed 7.5 N/mm2
. The
depth of the section is 400 mm. calculate the necessary width of the section.
9. The moment of inertia of the rolled steel joist girder of symmetrical section
about NA is 2640x104
mm4
. The total depth of the girder is 240 mm. determine
the longest span when simply supported such that the beam would carry a udl
of 5KN/m run and the bending stress should not exceed 120 N/mm2
.
10. Find the dimensions of a timber joist span of 10 m to carry a brick wall 0.2m
thickness and 4 m height if the weight of brick walls 19KN/m3
and the maximum
permissible stress is not to exceed 8 N/mm2
. The depth of the joist is twice of
its width.
11. A cantilever of a span 1.5m carries a point load of 5 KN at the free end. Find
the modulus of section required, if the bending stress is not to exceed 150
N/mm2
.
12. A wooden beam of rectangular section 100 mm x200 mm is simply supported
over span of 6m. Determine the udl it may carry if the bending stress is not to
exceed 7.5 N/mm2
. Estimate the concentrated load it may carry at the centre
of the beam with the same permissible stress.
13. A cast iron water pipe 450 mm and 20 mm thick is simply supported at two
points 6m apart. Assuming each span as simply supported, find the maximum
stress in the metal when (i) the pipe running full (ii) the pipe is empty. Specific
weight of cast iron is 70 KN/m3
and that of water is 9.81KN/m3
.

SOM.PDF

Recommended

Recommended

More Related Content

Similar to SOM.PDF

Similar to SOM.PDF (20)

Recently uploaded

Recently uploaded (20)

SOM.PDF