DESIGN OF MACHINE ELEMENTS QUESTION BANK

R.M.K COLLEGE OF ENGINEERING
AND TECHNOLOGY
RSM NAGAR, PUDUVOYAL-601206
DEPARTMENT OF MECHANICAL ENGINEERING
ME6503 – DESIGN OF MACHINE ELEMENTS
V SEM MECHANICAL ENGINEERING
Regulation 2013
QUESTION BANK
PREPARED BY
R.ASHOK KUMAR M.E (Ph.D)

R.M.K COLLEGE OF ENGG AND TECH / AQ / R2013/ ME6503 / V / MECH / JUNE 2017 – NOV 2017
ME6503 – DESIGN OF MACHINE ELEMENTS QUESTION BANK by ASHOK KUMAR.R (AP / Mech) 2
ME6503 DESIGN OF MACHINE ELEMENTS
UNIT – I STEADY STRESSES AND VARIABLE STRESSES IN MACHINE
MEMBERS 10
Introduction to the design process - factors influencing machine design, selection of materials based
on mechanical properties - Preferred numbers, fits and tolerances – Direct, Bending and torsional
stress equations – Impact and shock loading – calculation of principle stresses for various load
combinations, eccentric loading – curved beams – crane hook and „C‟ frame- Factor of safety -
theories of failure – Design based on strength and stiffness – stress concentration – Design for variable
loading
UNIT – II SHAFTS AND COUPLINGS 8
Design of solid and hollow shafts based on strength, rigidity and critical speed – Keys, keyways and
splines - Rigid and flexible couplings.
UNIT – III TEMPORARY AND PERMANENT JOINTS 9
Threaded fasteners - Bolted joints including eccentric loading, Knuckle joints, Cotter joints – Welded
joints, riveted joints for structures - theory of bonded joints.
UNIT – IV ENERGY STORING ELEMENTS AND ENGINE COMPONENTS 9
Various types of springs, optimization of helical springs - rubber springs - Flywheels considering
stresses in rims and arms for engines and punching machines- Connecting Rods and crank shafts.
UNIT – V BEARINGS 9
Sliding contact and rolling contact bearings - Hydrodynamic journal bearings, Somerfield Number,
Raimondi and Boyd graphs, -- Selection of Rolling Contact bearings. TOTAL: 45 PERIODS
TEXT BOOK:
 Bhandari V, “Design of Machine Elements”, 3rd Edition, Tata McGraw-Hill Book Co, 2010.
 Joseph Shigley, Charles Mischke, Richard Budynas and Keith Nisbett “Mechanical
Engineering Design”, 8th Edition, Tata McGraw-Hill, 2008.
REFERENCES:
 Sundararajamoorthy T. V. Shanmugam .N, “Machine Design”, Anuradha Publications, Chennai, 2003.
 Robert C. Juvinall and Kurt M. Marshek, “Fundamentals of Machine Design”, 4th Edition, Wiley,
2005
 Alfred Hall, Halowenko, A and Laughlin, H., “Machine Design”, Tata McGraw-Hill Book
Co.(Schaum‟s Outline), 2010
 Bernard Hamrock, Steven Schmid,Bo Jacobson, “Fundamentals of Machine Elements”,2nd Edition,
Tata McGraw-Hill Book Co., 2006.
 Orthwein W, “Machine Component Design”, Jaico Publishing Co, 2003.
 Ansel Ugural, “Mechanical Design – An Integral Approach", 1st Edition, Tata McGraw-Hill Book Co,
2003.
 Merhyle F. Spotts, Terry E. Shoup and Lee E. Hornberger, “Design of Machine Elements” 8th Edition,
Printice Hall, 2003.

UNIT – I – STEADY STRESSES AND VARIABLE STRESSES IN
MACHINE ELEMENTS
PART - A
1.1) Define CAD.
1.2) What are the advantages of CAD?
1.3) What are the factors to be considered in the selection of materials for a machine
element?
1.4) How the machine design may be classified? [AU, Nov / Dec – 2016]
1.5) What is an adaptive design? [AU, Apr / May – 2015, May / Jun – 2016]
1.6) What is adaptive design? Where it is used? Give examples.
[AU, Nov / Dec – 2012]
1.7) How are materials classified?
1.8) What are the common materials used in mechanical engineering design?
[AU, Nov / Dec – 2015]
1.9) What are the mechanical properties to be considered in selecting a material for
engineering applications?
1.10) What are the mechanical properties of metals? List any four mechanical
prosperities. [AU, May / Jun - 2012]
1.11) What is meant by interchangeability?
1.12) What are the steps in machine design process? [AU, Apr / May – 2010]
1.13) How will you account for stress concentration in design of the machine parts ?
[AU, Apr / May – 2010]
1.14) What do you mean by Optimum design? [AU, Nov / Dec –2011]
1.15) What are the methods to reduce stress concentration? [AU, Nov / Dec –2008]
1.16) Define nominal, basic and actual size.
1.17) What is meant by tolerance?
1.18) Define limits of size.
1.19) Define limits and fits. [AU, Apr / May – 2015, May / Jun – 2016]
1.20) Define fits, clearance and interference.
1.21) What are the types of fits? [AU, Nov / Dec– 2008]
1.22) Write short notes on clearance fit and interference fit.

1.23) Explain transition fit.
1.24) What are unilateral and bilateral tolerances?
[AU, May / Jun - 2013, Nov / Dec – 2016]
1.25) Using the table for tolerances, find the types of fit, maximum and minimum
clearance of interference for 150 G7 – e8 combination.
1.26) The fit between a hole and a shaft is defined by  70 H9F7. Find the allowance.
1.27) What is hole basis system?
1.28) What is shaft basis system?
1.29) Define preferred numbers.
1.30) What is meant by standardization?
1.31) Mention some standard codes of specification of steels. [AU, Nov / Dec– 2008]
1.32) Define load. What are the different types of loads that can act on machine
components?
1.33) What are the factors that govern selection of materials while designing a machine
component? [AU, Nov / Dec– 2010]
1.34) What is steady and variable load?
1.35) What is impact load? [AU, Nov / Dec – 2015]
1.36) What is an impact load? Give example. [AU, May / Jun - 2012]
1.37) What is meant by shock and impact load?
1.38) What are the methods used to improve fatigue strength? [AU, Nov / Dec –2013]
1.39) List at least two methods to improve the fatigue strength. [AU, Nov / Dec –2014]
1.40) Define stress and strain.
1.41) Define Poisson’s ratio. [AU, Apr / May – 2011]
1.42) Explain the normal stress theory and its limitations [AU, Apr / May – 2010]
1.43) Which theory of failure is suitable for the design of brittle materials?
[AU, Nov / Dec – 2015]
1.44) Explain the different types of stresses.
1.45) What is meant by double shear? Give an example.
1.46) Define resilience [AU, Nov / Dec –2009, April / May – 2017]
1.47) Define modulus of resilience and proof resilience. [AU, April / May – 2017]
1.48) What in meant by modulus of rigidity?
1.49) Explain factor of safety. [AU, Apr / May – 2010]

1.50) Define factor of safety. [AU, Nov / Dec –2012, 2015]
1.51) List the important factors that influence the magnitude of factor of safety.
[AU, Nov / Dec –2011]
1.52) What is an S-N curve? [AU, Nov / Dec – 2016]
1.53) Explain stress - strain diagram with an example.
1.54) What is the yield point of the material?
1.55) The material of a shaft is changed from C40 steel to alloy steel to increase the
rigidity. Give your comment. [AU, April / May – 2017]
1.56) Define ultimate and breaking stress.
1.57) Explain working stresses.
1.58) Differentiate the stress distribution in a bar subjected to an axial force and beam
subjected to bending [AU, Apr / May – 2010]
1.59) What is factor of safety for brittle materials? [AU, Apr / May – 2011]
1.60) Discuss the factors affecting the selection of factor of safety.
1.61) Define Poisson's ratio and bulk modulus.
1.62) Give the relation between bulk modulus and Young's modulus.
1.63) Give the relation between Young's modulus and modulus of rigidity.
1.64) Calculate the force required to punch a circular blank of 60 mm diameter in a plate
of 5 mm thick. The ultimate shear stress of the plate is 350 N/mm2
.
1.65) Determine the force required to punch a hole of 20mm diameter in a 5mm thick
plate with ultimate shear strength of 250 MPa? [AU, Nov / Dec –2014]
1.66) A mild steel bar of 12mm diameter is subjected to an axial load of 50 KN in
tension. Find the magnitude of the induced stress.
1.67) A M.S. bar of diameter 12 mm and length 1 m is subjected to an axial load of 50
KN in tension and modulus of elasticity is 2 x 105MPa. Find the elongation of the
bar.
1.68) Steel flat 10 mm wide and 12 mm thick is bent into a circular arc of radius 12 m.
Find the maximum intensity of stress induced in the cross section.
1.69) How is the allowable stress estimated in ductile and brittle materials?
1.70) Define the term principal planes and principal stress
1.71) State the various theories of failure.

1.72) What are the various theories of failure?
[AU, May / Jun - 2013, Nov / Dec – 2016]
1.73) What is the maximum principal strain theory (Saint Vennant's theory)?
[AU, Nov / Dec – 2009]
1.74) State the maximum strain energy theory (Haigh's theory)
1.75) State the difference between straight beams and curved beams.
[AU, Nov / Dec –2012]
1.76) Why nonsymmetrical I and T sections are preferred in design of curved beams?
[AU, April / May – 2017]
1.77) What is eccentric loading?
1.78) Define stress concentration. [AU, May / Jun – 2012, 2016]
1.79) What is meant by stress concentration?
[AU, May / Jun - 2009, Nov / Dec –2011]
1.80) Give one method of reducing stress concentration in key slots.
[AU, May / Jun - 2012]
1.81) What are the sources of stress concentration in machine elements?
1.82) Define stress concentration factor.
1.83) Define stress concentration and stress concentration factor.
[AU, May / Jun – 2014]
1.84) How to avoid stress concentration? [AU, Nov / Dec –2012]
1.85) What are the methods of reducing stress concentration?
[AU, May / Jun - 2009]
1.86) What are the factors to be considered while designing machine parts to avoid
fatigue failure?
1.87) Define fatigue stress concentration factor.
1.88) Define (a) stiffness and (b) resilience [AU, May / Jun - 2009]
1.89) Describe the material properties of hardness, stiffness and resilience.
[AU, Nov / Dec –2013, May / Jun – 2016]
1.90) Differentiate between hardness and toughness of materials.
[AU, May / Jun – 2014]
1.91) What are the types and modes of fracture?
1.92) Explain soderberg and Goodman lines in details.

1.93) What is Geber theory [AU, Nov / Dec – 2009]
1.94) Write Soderberg equation for a machine component subjected to
(a)Combination of mean and variable torques
(b) Combination of mean and variable bending moments [AU, Nov / Dec – 2010]
PART –B
1.95) Discuss in detail about the factors influencing machine design.
[AU, May / Jun - 2012]
1.96) What are the factors influencing machine design? Explain it.
[AU, May / Jun – 2014]
1.97) Explain various phases in Design using a flow diagram and enumerate the factors
influencing the machine design. [AU, May / Jun - 2013]
1.98) What is factor of safety? List the factors to be considered while deciding the factor
of safety. [AU, May / Jun – 2014]
1.99) Write short notes on preferred numbers, fits and types of fits.
[AU, May / Jun - 2012]
1.100) What is meant by hole basis system and shaft basis system? Which one is
preferred and why? [AU, May / Jun - 2013]
1.101) Explain the maximum normal stress theory of failure (Rankine's theory)
1.102) Explain the maximum shear theory of failure (Guest's theory)
1.103) Explain distortion energy theory of failure (Hencky and Von Mises theory)
1.104) What is the difference between Gerber curve and soderberg and Goodman lines?
[AU, May / Jun - 2013]
1.105) Explain notch sensitivity. What are the factors that affect notch sensitivity?
1.106) Explain in detail the maximum shear stress theory [AU, Nov / Dec – 2009]
1.107) Explain soderberg and Goodman lines in details. [AU, Nov / Dec – 2009]
1.108) Discuss in detail about CAD and optimum design. State their relevance in
designing mechanical elements. [AU, Nov / Dec – 2008]
1.109) Write short notes on the following: [AU, May / Jun – 2014]
 Interchangeability
 Tolerance
 Allowance

1.110) Define Stress concentration. Give some methods of reducing stress
concentration. [AU, Nov / Dec –2011]
1.111) The dimensions of mating parts, according to basic hole system are given as
follows:
Hole: 25mm Shaft: 24.97mm
25.02mm 24.95mm
Find the hole tolerance, shaft tolerance and allowance.
1.112) The following results were obtained in a tensile test on a mild steel specimen of
original diameter of 20 mm and guage length 40 mm. At the limit of proportionality,
the load was 80000 N and extension is 0.048 mm. The specimen yielded at a load of
85000 N and the maximum load was 150000 N. When two parts are fitted together
after being broken, the guage length was found to be 55.6 mm and the diameter at
neck was 15.8 mm. Calculate the Young’s modulus, stress at the limit of
proportionality, yield stress, ultimate stress, percentage elongation and reduction and
working stress. Take factor of safety = 2
1.113) Consider two aluminum rods and one steel rod combined as one unit which
supports a weight of 1000 kg. If the area of cross section of aluminum and steel rods
is 2 cm2
each and strains are equal, find the stresses acting on aluminum and steel
rods.
2626
/10x1.2/10x7.0 cmkgfEcmkgfE steelAl 
1.114) An unknown weights falls through 10mm onto a collar which is rigidly attached
to the lower end of a vertical bar 3 m long and 600 mm2
cross section. The maximum
instantaneous extension is 2mm. What is the corresponding stress and the value of
the weight? Take E = 200 kN/mm2
. [AU, Nov / Dec –2014, 2015, 2016]
1.115) A flat bar 32 mm wide and 12 mm thick is loaded by a steady tensile load of 85
kN. The material is mild steel with yield point stress of 315 N/mm2
. Find the factor
of safety based on the yield point. [AU, Nov / Dec – 2008]
1.116) A flat plate of width 60 mm has a central hole of 10 mm diameter. If the plate is
subjected to an axial tensile load of 10 kN, determine the thickness of the plate.
Assume yield point stress 300 MPa and factor of safety as 2.5.
[AU, Nov / Dec – 2008]

1.117) A shaft is transmitting 100 KW at 160 rpm. Find the suitable diameter of the
shaft if the maximum torque transmitted exceeds the mean by 25%. Take the
maximum allowable shear stress as 70 MPa.
1.118) A cast iron pulley transmits 10kW at 400rpm. The diameter of the pulley is 1.2m
and it has four straight arms of elliptical cross section in which the major axis is
twice of the minor axis. Determine the dimension of the arm if the allowable bending
stress is 15MPa. [AU, May / Jun - 2009]
1.119) A shaft is supported in bearings, the distance between their centers being 1 m. It
carries a pulley in the centre and it weighs 1 KN. Find the diameter of the shaft, if
the permissible bending stress for the shaft material is 40 N/mm
2
.
1.120) Determine the diameter of circular rod made of ductile material with endurance
limit is 265MPa and tensile yield strength of 350MPa. The member is subjected to a
varying axial load form – 300kN to 700kN and has a stress concentration factor is
1.8. The factor of safety as 2. [AU, May / Jun - 2009]
1.121) Two rods made of plain carbon steel 40C8 (Syt= 380 N/mm2
) are connected by
means of cotter joint. The diameter of each rod is 50mm and the cotter is made of
steel plate of 15mm thickness. Calculate the dimension of the socket end making the
following assumptions. (i) the yield strength in compression is twice of the tensile
yield strength and (ii) the yield strength in shear is 50% of the tensile yield strength.
Factor of safety is 6. [AU, Nov / Dec – 2009]
1.122) It is desired to bend a strip of 6 mm thick and 20 mm wide of spring steel into a
loop with the end overlapping and riveted. Find the minimum radius of the loop if
the stresses due to bending are limited to 100 MPa. Also determine the bending
moment required to bend the strip. Take Young’s modulus .10x1.2 5
MPaE 
1.123) A rod of linkage mechanism made up of steel 40Crl (Sut = 550N/mm2
) is
subjected to completely reversed axial load of 100kN. The rod is machined on the
lathe and expected reliability is 95%. There is no stress concentration. Determine the
diameter of the rod using a factor of safety of 2 for an infinite life condition.
[AU, Nov / Dec – 2009]
1.124) A shaft transmits 20 KW power and rotates at 500 rpm. The material of shaft is
50 C4 and the factor of safety is 2.

Determine the diameter of the shaft on the basis of its shear strength
Determine the diameter of shaft on the basis of its torsional rigidity, if the
permissible angle of twist is 30
per meter length and the modulus of rigidity
of the shaft material is 79300 N/mm2
. [AU, May / June – 2007]
1.125) Design a suitable diameter for a circular shaft required to transmit 90 KW at 120
rpm. The shear stress for the shaft is not to exceed 70 N/mm2
and the maximum
torque exceeds the mean by 40 %.
1.126) The shaft of an overhang crank is subjected to a force F of 2kN as shown in
figure. The shaft is made of 30Mn2 steel having an allowable shear strength equal to
100N/mm2
. Determine the diameter of the shaft.
[AU, Apr / May – 2015, May / Jun – 2016]
1.127) A weight W falls 10mm on a collar rigidity attached to the lower end of vertical
part 6m long 400mm2
in cross section. The maximum instantaneous extension is
found to be 2mm. Take Young’s modulus 2 * 105
N/mm2
. Find the value W and
impact stress induced
1.128) A bolt is subjected to a direct tensile load of 25kN and shear load of 15kN.
Considering various theories of failure, determine the suitable size of bolt if the yield
stress in tension is 250N/mm2
. Take FOS as 2 and Poisson’s ratio as 0.3
[AU, Nov / Dec – 2008]
1.129) An I-section beam of depth 250 mm is supported at two points 4 m apart. It is
loaded by a weight of 4 KN falling through a height h and striking the beam at mid
span. The moment of inertia of the section is 8 x 107
mm4
; E = 210 KN/ mm2
.
Determine h if the stress is 120 N/mm2
.

1.130) A man weighing 60 kg jumps from a height of 50 cm on a diving board of
rectangular cross - section having 30 cm width and 2 m long. If the maximum induced
stress is limited to 400 kg/cm2 and the modulus of elasticity of the board is 1 x
105kg/cm2, find the thickness of the diving board.
1.131) A cantilever beam of span 800mm carries a uniformly distributed load of
12kN/m. the yield value of material of cantilever is 400MPa. Factor of safety is 2.5
find the economical section of cantilever among (i) circular cross section of diameter
‘d’ (ii)rectangular cross section of depth ‘d’ and width ‘w’ d/w= 2.5 (iii) ‘I’ section
of total depth 7t width 5t where ‘t’ is thickness. Find the dimension and cross
sectional area of the economic section [AU, Apr / May – 2010]
1.132) A vertical pillar of 50 mm diameter is subjected to a vertical load of 1 kN acting
eccentrically at a distance of 30 mm from the axis. Calculate the maximum stress in
the pillar and locate it.
1.133) A hollow circular column of external diameter 250 mill and internal diameter
200 mm carries a projecting bracket on which a load of 20 kN rests, as shown in Fig.
The centre of the load from the centre of the column is 500 mm. Find the stresses at
the sides of the column. All dimensions in mm. [AU, Nov / Dec – 2016]

1.134) A shaft of diameter 40 mm is used to transmit the power of 30 KW at 710 rpm
and is supported in bearings 500 mm apart. A load of 10 KN is concentrated at the
centre of shaft vertically. Calculate the maximum principle stress and shear stress.
1.135) A hollow shaft is required to transmit 600 kW at 110 rpm, the maximum torque
being 20% greater than the mean. The shear stress is not to exceed 63 Mpa and twist
in a length of 3 meter not to exceed 1.4 degrees. Find the external diameter of the
shaft, if the internal diameter to the external diameter is 3/8. Take modulus of rigidity
as 84 Gpa. [AU, Apr / May 2011]
1.136) Determine the diameter of a steel bar, which is of ductile nature subjected to an
axial tensile of 60kN and torsional moment of 1600N-m. Use the factor of safety of
2.5, E= 200GPa [AU, Apr / May – 2010]
1.137) A shaft as shown in figure is subjected to a bending load of 3kN, pure torque of
1000 N-m and an axial pulling force of 15kN. Calculate the stress at A and B
[AU, Apr / May – 2010, May / Jun – 2016]

1.138) A cantilever beam made of cold drawn carbon steel of circular cross section as
shown in fig ., is subjected to a load which varies from –F to 3 F. Determine the
maximum load that this member can withstand for an indefinite life using a factor of
safety as 2. The theoretical stress concentration factor is 1.42 and the notch
sensitivity is 0.9.
Assume the following values:
Ultimate stress =550 Mpa
Yield stress = 470 Mpa
Endurance limit = 275 Mpa
Size factor = 0.85
Surface finish factor = 0.89. [AU, Apr / May – 2011]
1.139) A simply supported beam has concentrated load at the centre which fluctuates
a value from P to 4P. The span of the beam is 500 mm and its cross section is circular
with a diameter of 60 mm. Beam material is cold drawn 0.2% carbon steel. Calculate
the maximum permissible value of P for a factor of safety of 1.3. Beam surface is
ground [AU, Nov / Dec – 2010]
1.140) A wall crane with a pin - joint tie rod is as shown in Fig. The crane hook is to
take a maximum load 35 kN, when the load is at a distance of 2 m from the wall. The
tie rod and pin are made of steel FeG 250 (Syt = 250 N/mm2
) and the factor of safety
is 5. Calculate the diameter of the tie rod and the pin. [AU, April / May – 2017]

1.141) The C frame of 100kN capacity press is shown in fig. the material of the frame
is grey cast iron an d the factor of safety is 3 determine the dimensions of the frame
[AU, Apr / May – 2010]
1.142) The frame of a punch press is shown in fig. Find the stresses at the Inner and
outer surface at section X-X of the frame, if W = 5000 N. [AU, May / Jun – 2014]

1.143) A bracket as shown in figure is bolted to the frame - work of a machine which
carries a load P. The cross - section of the bracket is rectangle with 30 mm wide and
60 mm deep. If the maximum stress is limited to 30 N/mm2
, find the value of P.
[AU, Apr / May – 2011]
1.144) A mild steel bracket is shown in figure. It is subjected to a pull of 6000 N acting
at 450
to the horizontal axis. The bracket has a rectangular section whose depth is
twice the thickness. Find the cross sectional dimensions of the bracket if the
permissible stress in the material is 60MPa [AU, Nov / Dec – 2012]
1.145) A cast-iron link, as shown in figure, is to carry a load of 20 kN. If the tensile and
compressive stresses in the link are not to exceed 25 MPa and 80 MPa respectively,
obtain the dimensions of the cross- section of the Link at the middle of its length.
[AU, Nov / Dec –2013]

1.146) A bell crank is driving a condenser air pump. A force of 8000 N is acting on the
pin A. The lever is a steel forging turning on a pin as the fulcrum. Design the bell
crank lever assuming the following data: Allowable stress in tension 80 N/mm2
and
allowable stress in shear 62 N/mm2
for the pin. [AU, April / May – 2017]
1.147) A mild steel bracket is shown in figure. It is subjected to a pull of 5000 N acting
at 450
to the horizontal axis. The bracket has a rectangular section whose depth is
twice the thickness. Find the cross sectional dimensions of the bracket if the
permissible stress in the material is 50 N/mm2
[AU, Nov / Dec – 2005, 2007]
1.148) A link shaped in the form of a letter S is made up of 30 mm diameter bar, as
shown in fig. Determine the maximum tensile stress and maximum shear stress in
the link. [AU, April / May – 2017]

1.149) The crank hook carries a load of 20KN as shown in figure. The section at X –X
is rectangular whose horizontal side is 100 mm. Find the stresses in the inner and
outer fibers at the given section
1.150) A C-clamp is subjected to a maximum load of W, as shown in figure. If the
maximum tensile stress in the clamp is limited to 140 MPa., find the value of the
load W. [AU, Nov / Dec –2012]

1.151) Determine the maximum shear stress induced in the member loaded as shown in
figure.
1.152) A cylindrical bar of 50 mm diameter and 250 mm long is fixed at one end. At the
free end it is loaded as shown in figure with axial load of 15 KN, a downward
transverse load of 5KN and a torque of 2 KNm. Calculate the maximum stress at point
A of the bar.
1.153) A bolt is subjected to a direct load of 25 KN and a shear load of 15 KN.
Considering the various theories of failure, determine a suitable size of the bolt, if

the material of the bolt is C15 having 200 N/mm2
yield strength.
[AU, May / June – 2007]
1.154) A shaft of diameter 50 mm is subjected to a bending moment of 20 Nm and torque
15 Nm and the yield stress is 200 N/mm2
. Find the factor of safety according to all
theories of failure.
1.155) A steel member is subjected to a 3 dimensional stress system and the resulting
principal stresses are 120 N/mm2
tension, 80 N/mm2
and 40 N/mm2
compression. If
the proportional limit of the material in simple tension is 280 N/mm2
and its Poisson’s
ratio is 0.3, determine the factor of safety according to
(a) Maximum principal stress theory
(b) Maximum principal strain theory
(c) Maximum shear stress theory.
1.156) A machine part is statically loaded and has a yield point strength of 350 N/mm2
.
If the principal stresses are 70 N/mm2
and 35 N/mm2
, both tensile, find the factor of
safety for the following cases. [AU, Nov / Dec – 2015, 2016]
(i) Maximum normal stress theory
(ii)Maximum shear stress theory and
(iii)Distortion energy theory.
1.157) A bolt is subjected to an axial pull of10 kN and a transverse shear force of 5 kN.
The yield strength of the bolt material is 300 MPa. Considering a factor of safety of
2.5. Determine the diameter of the bolt, using (i) maximum normal stress theory, (ii)
maximum shear stress theory, and (iii) maximum principal strain theory. Take
Poisson's ratio as 0.2. [AU, Nov / Dec – 2015]
1.158) A solid circular shaft of diameter 45 mm is loaded by bending moment 650 Nm,
torque 900 Nm and an axial tensile force of 30 kN. The shaft material is ductile with
yield strength of 280 MPa. Determine the factor of safety according to Maximum
principal stress, Tresca and Von misses theories of failure. [AU, April / May – 2017]
1.159) A compound bar of 3m length made up of copper having E = 105GN/m2
and the
other of steel having = 210GN/m2
. Each bar is 25mm broad and 12.5mm thick. This
component bar is stretched by a load of 50kN. Find the increase in length of the
compound bar and the stress produced in the steel and copper. The length of copper
as well as of steel bar is 3m each. [AU, Nov / Dec - 2011]

1.160) A tie - bar has to carry a load of 100 KN. What must be the thickness of bar of
110 mm width, if there is a rivet hole of 22 mm diameter on its, centre line? Working
stress for the tie bar is 75MPa
1.161) A stepped shaft of diameters D and d is subjected to a variable axial load P which
cyclically varies between 0 and 10 KN. The shaft is made of C20 steel, mirror
polished with Su= 500 N/mm2 and Sy = 260 N/mm2. Determine the diameters D and
d with D/d = 1.5, factor of safety = 2, notch sensitivity factor = 0.8 and r/d = 0.2
where r is the shoulder radius.
1.162) A steel rod of yield strength 350N/mm2
and endurance limit of 265 N/mm2
is
subjected to axial load of which varies from -300kN to 700kN and has a stress
concentration factor 1.8. Assume FOS as 2. Calculate the diameter of steel rod
[AU, Apr / May – 2011]
1.163) Determine the thickness of a 120mm wide uniform plate for safe continuous
operation if the plate is to be subjected to a tensile load that has maximum value of
250kN and a minimum values 100kN. The properties of the plate as follows.
Endurance limit stress = 225MPa and yield pint stress 300MPa. The factor of safety
based on yield point may be taken as 1.5. [AU, Nov / Dec - 2011]
1.164) A hot rolled steel shaft of 40mm diameter is subjected to a torsional moment that
varies from 330 Nm to – 110 Nm and an applied bending moment which rises from
440 Nm to –220 Nm. The material of the shaft has an ultimate strength of 550 MN/m2
and yield strength of 410 MN/m2
. Find the approximate factor of safety using

soderberg equation allowing endurance limit to be half the ultimate strength and size
factor and surface finish factor to be 0.85 and 0.62 respectively.
[AU, Nov / Dec – 2008]
1.165) A hot rolled steel shaft is subjected to a torsional moment that varies from 330
Nm clockwise to 110 Nm counter clockwise and an applied bending moment at a
critical section varies from 440 Nm to -220 Nm The shaft is of uniform cross- section
and no keyway is present at the critical section. Determine the required shaft
diameter. The material has an ultimate strength of 550 MPa and yield strength of410
MPa. Take the endurance limit as half the ultimate strength, factor of safety of 2, size
factor of 0.85 and a surface finish factor of 0.62. [AU, Nov / Dec –2013]
1.166) A plate of 12 mm thick, with two holes as indicated in figure below is subjected
to a tensile load of 20 KN. Calculate the stresses at both the holes.
[AU, Nov/Dec – 2004]
1.167) A medium force fit on a 50 mm shaft requires a hole tolerance of 0.025 mm and
a shaft tolerance of 0.016 mm. The maximum interference is to be 0.042 mm. How
will you dimension the hole and the shaft, if hole deviation is H?
[AU, Nov / Dec – 2010]
1.168) A plate of uniform thickness t has two width 45 mm and 30 mm with a fillet
radius of 5 mm. The smaller width portion has a transverse hole of 15 mm diameter
for plate material. The ultimate strength is 200 N/mm2
. Consider stress concentration
factor and assume F.S = 2.5. Find the thickness of the plate for maximum tensile
load of 5 KN. [AU, Nov / Dec – 2006]
1.169) Determine the maximum stress involved in the following cases taking stress
concentration into account.
Case
i) A rectangular plate with a hole under an axial load of 10 KN.

ii) A circular shaft with a step under an axial load of 10 KN.
iii)A shaft under a bending moment of 50 Nm.
iv) A shaft under a twisting moment of 50 Nm.
1.170) A machine component is subjected to a flexural stress which fluctuates between
+300 MN/m2
and -150 MN/mm2
. Determine the value of minimum ultimate strength
according to
i) Gerber relation
ii) Modified Goodman relation
iii)Soderberg relation
Take yield strength = 0.55 ultimate strength; endurance strength = 0.5 ultimate
strength; factor of safety = 2.
1.171) A machine component is subjected to fluctuating stress that varies from 40 to
100 N/mm2
. The corrected endurance limit stress for the machine component is 270
N/mm2
. The ultimate tensile strength and yield strength of material are 600 and 450
N/mm2
respectively. Find the factor of safety using:
(1) Gerber theory
(2) Soderberg line
(3) Goodman line and
(4) Also, find factor of safety against static failure. [AU, May / Jun - 2013]
1.172) A cantilever rod of circular section is subjected to a cyclic transverse load
varying from -100N to +300 N as shown in figure. Determine the diameter d of the
rod by
i) Goodman method ii) Soderberg method.
Using the following data :
Factor of safety = 2; theoretical stress concentration factor = 1.4; notch sensitivity
factor = 0.9; ultimate strength = 550 MPa ; endurance strength = 275 MPa; size
correction factor = 0.85 surface correction factor = 0.9 ; yield strength = 320 MPa

1.173) A cantilever rod of length 120 mm with circular section is subjected to a cyclic
transverse load; varying from -100 N to 300 N at its free end. Determine the diameter
‘d’ of the rod, by (i) Goodman method and (ii) Soderberg method using the following
data. Factor of safety = 2; Theoretical stress concentration factor = 1.4; Notch
sensitivity factor = 0.9; Ultimate strength= 550 MPa; Yield strength = 320 MPa;
Endurance limit = 275 MPa; Size correction factor = 0.85; Surface correction
factor= 0.9. [AU, Nov / Dec – 2015]
1.174) Determine the cross - section of C frame shown in figure to withstand a
maximum load of 25KN. Permissible stress in tension is 100 N/mm2
. Find also the
stresses at X - X. Assume h = 2b
1.175) A cylindrical shaft made of steel of yield strength 700 MPa is subjected to static
loads consisting of bending moment 10 KN-m and a torsional moment 30 KN-m.
Determine the diameter of the shaft using two different theories of failure and
assuming a factor of safety of 2. Take E = 210 GPa and Poisson's ratio = 0.25.
[AU, Nov / Dec – 2012]
1.176) A shaft is subjected to a bending moment varying from - 200 Nm to 500 Nm and
a twisting moment varying from 50 Nm to 175 Nm. The material used has SU = 600
MPa ; Se = 300 MPa; Ka = 0.76; Kb = 0.85; Kc = 0.897; Kt = 1.85 and q = 0.95.
Find the diameter of the shaft by Von Misses Hencky theory. Factor of safety is 1.5
[AU, Nov / Dec – 2003]

1.177) In an elastic material, principal stresses are tensile and compressive and the ratio
being 4 : 1. Determine the limiting stress according to different theories of failure if
the tension test gives the elastic limit of the material as 400 N/mm2
. Assume Poisson's
ratio as 0.3.
1.178) A hot rolled steel shaft is subjected to a torsional load varying from 300 Nm
clockwise to 150 Nm counter clockwise and to a bending moment at a critical section
varying from 400 Nm positive to 200 Nm negative. The shaft has uniform cross -
section and no keyway is present at the critical section. Determine the required shaft
diameter assuming σu = 500 N/mm2
, σy = 400 N/mm2
and n = 2
1.179) A rod of a linkage mechanism made of steel 40Crl(σut = 550 N/mm2
) is subjected
to a completely reversed axial load of 100 kN. The rod is machined on lathe and the
expected reliability is 95%. There is no stress concentration. Determine the diameter
of the rod using a factor of safety of 2 for an infinite life condition.
[AU, Nov / Dec – 2009]
1.180) Determine the diameter of a circular rod made of ductile material with a
endurance limit is 265 MPa and a tensile yield strength of 350 MPa. The member is
subjected to a varying axial load from – 300 kN to 700 kN and has a stress
concentration factor is 1.8. Take factor of safety as 2. [AU, May / June - 2009]
1.181) A shaft of diameter 'd' is subjected to a torque varying between 900 Nm to 1800
Nm. Assuming a factor of safety 2 and a stress concentration factor of 1.2, find the
diameter of the shaft. Take σu = 650 N/mm2
σy = 480 N/mm2
, Size factor B =
0.85 and surface finish factor C = 0.5. [AU, Nov / Dec –2014]
1.182) A cast iron pulley transmits 10 kW at 400 rpm. The diameter of the pulley is 1.2
metre and it has four straight arms of elliptical cross-section, in which the major axis
is twice the minor axis. Determine the dimensions of the arm if the allowable bending
stress is 15 MPa. [AU, May / June - 2009]

1.183) A Cast iron pulley transmits 10 kW at 400 rpm. The diameter of the pulley is 1.2
m and it has four straight arms of elliptical cross-section, in which the major axis is
twice the minor axis. Determine the dimensions of the arm if the allowable bending
stress is 15 MPa. [AU, Nov / Dec –2011]
1.184) A circular bar of length 600mm is supported at its ends. It is acted upon by a
concentrated cyclic load at its centre which varies from 20 KN to 50 KN. If the factor
of safety is 1.5, surface finish factor is 0.9 and the size effect is 0.85. Find the
diameter of the bar. The ultimate strength of the bar is 650 N/mm2
, yield strength is
500 N/mm2
and endurance strength is 350 N/mm2
.
1.185) A circular cross section C45 steel member is subjected to an axial load that varies
from -1000N to 2500N and the torsional moment that varies from 0 to 500Nm.
Assume a factor safety of 1.5 and a stress concentration factor of 1.5. Estimate the
required diameter of the member for indefinite life. [AU, April / May – 2017]
1.186) A 50 mm diameter shaft is made from carbon steel having an ultimate tensile
strength of 630 MPa. It is subjected to a torque, which fluctuates between 2000 Nm
to – 800 Nm. Using Soderberg methods, calculate the factor of safety.
1.187) A simply supported beam has a concentrated load at the center which fluctuates
from a value of P to 4P. The span of the beam is 500 mm and its cross section is
circular with a diameter of 60 mm. Taking for the beam material an ultimate stress
of 700 MPa, a yield stress of 500 MPa, endurance limit of 330 MPa for reversed
bending, and a factor of safety 1.3, calculate the maximum value of P. Take a size
factor of 0.85 and a surface finish factor of 0.9. [AU, Nov / Dec – 2007]
1.188) A steel cantilever is 200 mm long. It is subjected to an axial load, which varies
from 150 N (compression) to 450 N (tension) and also a transverse load at its free
end, which varies from 80 N up to120 N down. The cantilever is of circular cross
section. It is of diameter 2d for the first 50 mm and of diameter d for the remaining
length. Determine its diameter taking a factor of safety 2 Assume the following
values: [AU, May / Jun – 2016]

Yield stress = 330 MPa
Endurance limit in reversed loading = 300 MPa
Correction factors = 0.7 in reversed axial loading
= 1.0 in reversed bending
Stress concentration factor = 1.44 for bending
= 1.64 for axial loading
Size effect factor = 0.85
Surface effect factor = 0.90
Notch sensitivity index = 0.90
1.189) A pulley is keyed to a shaft midway between two antifriction bearings. The
bending moment at the pulley varies from – 170 Nm to 510 Nm as the torsional
moment in the shaft varies from 55 Nm to 165 Nm. The frequency of the variation of
the load is the same as the shaft speed. The shaft is made of cold drawn steel having
an ultimate strength of 538 MPa and yield strength of 400 MPa. Determine the
required diameter for an indefinite life. The stress concentration factor for the
keyway in bending and torsion may be taken as 1.6 and 1.3 respectively. Correction
factor A = 1 (for bending) A = 0.6 (for torsion) B = 0.85, C = 0.88. Use a design
factor N = 1.5 [AU, April / May – 2004, May / Jun - 2012]
1.190) A pulley is keyed to a shaft midway between two antifriction bearings. The
bending moment at the pulley varies from – 160 Nm to 500 Nm as the torsional
moment in the shaft varies from 60 Nm to 160 Nm. The frequency of the variation of
the load is the same as the shaft speed. The shaft is made of cold drawn steel having
an ultimate strength of 540 MPa and yield strength of 400 MPa. Determine the
required diameter for an indefinite life. The stress concentration factor for the
keyway in bending and torsion may be taken as 1.6 and 1.3 respectively. The factor
of safety is 1.5, size factor = 0.80 and surface finish factor = 0.85
[AU, May / Jun - 2012]
1.191) A pulley is keyed to a shaft midway between two bearings. The shaft is made of
cold drawn steel for which the ultimate strength is 550MPa and the yield strength is
400MPa. The bending moment at the pulley varies from -150 N-m to 400 N-m as

the torque on the shaft varies from -50N-m to 150N-m. Obtain the diameter of the
shaft for an indefinite life. The stress concentration factors for the keyway at the
pulley in bending and in torsion are 1.6 and 1.3 respectively. Take the following
values: Factor of safety = 1.5; load correction factors = 1.0 in bending and 0.6 in
torsion; Size factor = 0.85; Surface effect factor = 0.88. [AU, Nov / Dec –2012]
1.192) A transmission shaft made of C 45 steel is subjected to a fluctuating torque
varying from –100 Nm to + 500 Nm. Also, a fluctuating BM acts on the shaft, which
varies from +500 Nm to – 500 Nm. Kt = 2. FS = 1.5. Determine the required
diameter of the shaft. [AU, Nov / Dec – 2005]
1.193) A transmission shaft made of C45 steel is subjected to a fluctuating torque
varying from -100N-m to +500N-m. Also a fluctuating bending moment acts on the
shaft, which varies from +500N-m to -500N-m. Let the stress concentration factor
be 2. The shaft is machined for a FOS 1.5. Determine the required diameter of the
shaft. [AU, April / May – 2010]
1.194) A steel bar is subjected to a reverse axial load of 180kN. Find the diameter of
the bar for a design factor of 2. Ultimate tensile strength 1070N/mm2
, yield strength
910N/mm2
. Endurance limit in bending is half of ultimate strength. Use the following
data. Load factor = 0.7, surface finish factor = 0.85 and stress concentration factor 1
[AU, May / Jun - 2012]
1.195) A bar of circular cross section is subjected to alternating tensile forces varying
from a minimum of 200 KN to a maximum of 500 KN. It is to be manufactured of a
material with an ultimate tensile strength of 900 MPa and an endurance limit of 700
MPa. Determine the diameter of the bar using safety factors of 3.5 related to ultimate
tensile strength and 4 related to endurance limit and a stress concentration factor of
1.65 for fatigue load. Use Goodman straight line as basis for design.
1.196) A circular bar of 500 mm length is supported freely at its two ends. It is acted
upon by a central concentrated cyclic load having a minimum value of 20 kN and a
maximum value of 50 kN. Determine the diameter of bar by taking a factor of safety
of 1.5, size effect of 0.85, surface finish factor of 0.9. The material properties of bar
are given by, ultimate strength of 650 MPa, Yield strength of 500 MPa and
Endurance strength of 350 MPa. [AU, Nov / Dec –2011, 2016]

UNIT – II – SHAFTS AND COUPLINGS
Part – A
2.1) What is meant by a shaft?
2.2) What are the types of the shaft?
2.3) Distinguish between shaft, axle and spindle from the design point of view.
2.4) What is the difference between spindle and axle? [AU, Nov / Dec – 2016]
2.5) What are the materials used in shafts? [AU, Nov / Dec – 2015]
2.6) How are shafts formed?
2.7) State any four reasons for preferring hollow shaft over solid shaft.
2.8) What are the advantage of hollow shafts? [AU, April / May – 2017]
2.9) What is meant by Jack shaft? [AU, April / May – 2010]
2.10) What are the factors to be considered for the selection of shaft materials?
2.11) What is meant by design of a shaft based on rigidity? [AU, Nov / Dec – 2015]
2.12) What are the types of stresses induced in shafts? [AU, Nov / Dec –2011]
2.13) Name the stresses induced in the shaft. [AU, April / May – 2011]
2.14) What are the various stresses induced in the shafts? [AU, May / Jun – 2014]
2.15) What are the various stresses induced in the shafts? [AU, May / Jun – 2014]
2.16) Why is maximum shear stress theory is been used for shaft?
[AU, Nov / Dec - 2009]
2.17) What is the significance of slenderness ratio in shaft design?
[AU, Nov / Dec - 2008]
2.18) Why a hollow shaft has greater strength and stiffness than solid shaft of equal
weight? [AU, April / May – 2011, Nov / Dec –2012, May / Jun – 2016]
2.19) What do you mean by stiffness and rigidity with reference to shafts?
[AU, Nov / Dec - 2010]
2.20) Why is maximum shear stress used for shaft? [AU, Nov / Dec - 2009]
2.21) Define variable load? [AU, April / May – 2010]
2.22) What are the theories of failure used in design of shafts? [AU, Nov / Dec –2012]
2.23) Suggest suitable couplings for
(a) Shaft with parallel misalignment

(b) Shafts with angular misalignment of 10°
(c) Shafts in perfect alignment [AU, Nov / Dec - 2010]
2.24) Explain the significance of slenderness ratio in shaft design.
2.25) Define the term critical speed of the shaft. [AU, Nov / Dec – 2016]
2.26) What is meant by critical speed?
2.27) What is meant by critical speed of shaft? [AU, April / May – 2010]
2.28) What is the effect of key ways cut into the shaft? [AU, May / Jun – 2016]
2.29) How the length and diameter of a shaft affects its critical speed?
[AU, Apr / May – 2015, Nov / Dec – 2016]
2.30) What is meant by equivalent bending moment [AU, May / Jun - 2012]
2.31) Define equivalent torsional moment of a shaft [AU, April / May – 2017]
2.32) Sketch the cross section of a splined shaft. [AU, May / Jun - 2012]
2.33) A shaft is used to transmit 25 KW at 1500 rpm. The material used is 30 C8 steel.
σy = 300 MPa. Find the diameter of the shaft.
2.34) A shaft of 70mm long is subjected to shear stress of 40 MPa and has an angle of
twist equal to 0.017 radian. Determine the diameter of the shaft. Take G=80 GPa.
[AU, Nov / Dec –2013]
2.35) The shaft of diameter 60 mm is subjected to shear stress of 40 MPa and has an
angle of twist equal to 0.01 radian. Determine the length of the shaft for G = 8 *
105
MPa.
2.36) A hollow steel shaft 3 m long transmits 25 KNm torque. The total angle of twist
not exceeding 2° and permissible shear stress is equal to 60 MPa. Find the inner and
outer diameter of the shaft G = 0.8 * 105
MPa.
2.37) Shaft A has diameter which is double the diameter of shaft B of same material
and transmit 80 kW if both shafts rotate at same speed, what is the power
transmitted by shaft B [AU, Nov / Dec –2014]
2.38) What is a key? Where is it used? On what basis is it selected?
2.39) What is key? State its functions. [AU, Nov / Dec –2011]
2.40) What is the function of key? [AU, April / May – 2011]
2.41) What is the function of keys? List types of keys [AU, Nov / Dec –2012]
2.42) How are keys classified?
2.43) Discuss forces on keys. [AU, Nov / Dec –2014]

2.44) For any sunk key, the crushing strength should be at least twice the shear strength.
Prove it.
2.45) What is the main use of woodruff keys? [AU, May / Jun, Nov / Dec –2013]
2.46) What are the advantages of Woodruff keys when compared to others?
2.47) In what ways are splines superior to keys?
2.48) Differentiate between keys and splines.
[AU, May / June – 2009, 2012, Nov / Dec –2011]
2.49) What is coupling? [AU, May / June - 2009]
2.50) What are the different types of rigid couplings? [AU, April / May – 2011]
2.51) Name any two of the rigid coupling. [AU, May / Jun – 2014]
2.52) In what situation is flexible coupling is used? [AU, Nov / Dec – 2008, 2009, 2015]
2.53) Under what circumstances flexible couplings are used?
[AU, Nov / Dec –2012, May / Jun – 2016]
2.54) Differentiate between rigid coupling and flexible coupling.
[AU, May / Jun – 2016]
2.55) Where are spline couplings used?
2.56) State the reasons for which the couplings are located near the bearings.
2.57) Explain the modes of failure of keys.
2.58) What are the forces acting on keys when used for transmitting torque?
2.59) How is the strength of a shaft affected by the keyway?
2.60) State the applications of shaft coupling.
2.61) Name the various types of shaft couplings.
2.62) In which situations, flexible couplings are selected? [AU, Nov / Dec – 2009]
2.63) Name any two of the rigid and flexible couplings. [AU, May / Jun - 2013]
2.64) What are the types of flexible coupling and rigid couplings?
[AU, Nov / Dec – 2016]
2.65) What are the possible modes of failure of the pin (bolt) in a flexible coupling?
[AU, Nov / Dec – 2015]
2.66) What is the use of register in a flange coupling?
2.67) Explain the advantage of split muff coupling over solid muff coupling.
2.68) Explain the failure modes of couplings.

Part – B
2.69) Find the diameter of solid shaft to transmit 20kW at 200rpm. Take FOS 2 and the
shear stresses as 45MPa. If the hollow shaft is need instead of solid shaft. Find the
inside and outside diameter when the ratio between inside and outside diameter is
0.5.
2.70) Compare the weight, strength and stiffness of a hollow shaft of same internal
diameter as that of a solid shaft. The inside diameter of the hollow shaft is being
0.7times the external diameter. Both the shaft has same material and length.
[AU, May / Jun - 2012]
2.71) A solid shaft is to transmit 1000 kW at 120 rpm. Find the shaft diameter if the
shear stress is 80 N/mm2
. If the shaft is made hollow with internal diameter, find the
percentage saving in material, Take I.D = 0.6. [AU, Nov / Dec – 2015]
2.72) A hollow steel shaft transmits 500 KW at 1000 rpm. The maximum shear stress
is 50 N/mm2
. Find the outside and inside diameter of the shaft, if the outside diameter
is twice the inside diameter, assuming that the maximum torque is 20 % greater than
the mean torque.
2.73) A solid shaft of diameter d is used in power transmission. Due to modification of
existing transmission system, it is required to replace the solid shaft by a hollow shaft
of the same material and equally strong in torsion. Further, the weight of hollow shaft
per meter length should be half of the solid shaft. Determine the outer diameter of
hollow shaft in terms of d. [AU, Nov / Dec - 2009]
2.74) A solid circular shaft is subjected to a bending moment of 3000 N-m and a torque
of 10000 N-m. The shaft is made of 45C8 steel having ultimate tensile stress of 700
MPa and a ultimate shear stress of 500 MPa. Assuming a factor of safety as 6,
determine the diameter of the shaft. [AU, May / June - 2009]
2.75) A shaft of 30 KW, 710 rpm motor is 40 mm in diameter and is supported I n
bearings 500 mm apart. Calculate the
(i) Stress due to bending if the armature weighing 10,000 N concentrated at the
Centre acting vertically.
(ii)Stress due to torsion.
(iii)Equivalent shear stress and tensile stress due to bending moment and torque.

2.76) A line shaft rotating at 200 rpm is to transmit 20 KW power. The allowable shear
stress for the shaft material is 42 N/mm2
. If the shaft carries a central load of 900 N
and is simply supported between bearings 3 m apart, determine the diameter of the
shaft. The maximum tensile or compressive stress is not to exceed 56 N/mm2
.
2.77) The shaft of an axial flow rotary air compressor is subjected to a maximum torque
of 2kNm an maximum bending moment of 4kNm. The combined shear and fatigue
factors in torsion and bending may be taken as 1.5 and 2.0 respectively. Determine
the diameter of the shaft, the shear stress in shaft should not exceed 5.0MN/m2
[AU, Nov / Dec - 2008]
2.78) A shaft is to transmit 20KW at 250 rpm. It is supported on two bearings 750mm
apart and has two gears keyed to it. The pinion having 24 teeth of 6mm module is
located at 100mm to the left of the right hand bearing and delivers the power
horizontally to the right. The gear having 80 teeth, 6mm module is located at 150mm
to the right of left - hand bearing and receives power in a vertical direction from
below. Selecting suitable material, determine the required shaft size for a factor of
safety of 2.
2.79) A shaft is supported at its ends with ball bearing carries a straight tooth spur gear
at the mid span of the shaft and transmits 7.5kW at 300rpm. The pitch circle diameter
of the gear is 150mm. The distance between the centerline of bearing and gear is
100mm. If the shaft is made up of steel with allowable shear stress as 45MPa.
Determine the diameter of shaft take the pressure angle of the gear is 20º.

2.80) A steel shaft transmitting 12 KW at 250 rpm is supported on two bearings 700mm
apart and has keyed to it two gears. A - 20 teeth, 8 module gear is located at 120 mm
to the left of the right hand bearing and delivers power to a gear directly below the
shafts. A - 80 teeth, 16 module gear is located at 150 mm to the right of the left -
hand bearing and receives power from a gear directly above it. Sketch the bending
moment diagrams and determine the diameter of the shaft.
2.81) A line shaft is driven by a means of motor placed vertically below it. The pulley
on the line shaft with a diameter of 1.5m and has belt tension of 5.4kN and 1.8kN on
the tight side and slack side of the belt. Both the tension may be assumed vertically.
If the pulley overhangs from the shaft at a distance of 40mm from the line bearing.
Find the diameter of shaft. Take shear stress as 42MPa.
2.82) Power is transmitted to a shaft supported on bearings, 900 mm apart, by a belt
drive, running on a 450 mm pulley, which overhangs the right bearing by 200 mm.
Power is transmitted from the shaft through a belt drive, running on a 250 mm pulley,
located mid - way between the bearings. The belt drives are at right angle to each
other and the ratio of the belt tensions is 3; with the maximum tension in both the
belts being limited to 2 KN. Determine the diameter of the shaft, assuming
permissible tensile and shear stresses are 100 MPa and 60 MPa respectively.
[AU, Nov / Dec – 2004, 2005]
2.83) A shaft is to transmit 50 KW at 1200 rpm. It is also subjected to a bending moment
of 275 Nm. Allowable shear stress is 60 N/mm2
. The shaft is not to twist more than
20
in a length of 2m. G =80 * 103
N/mm2
. Design the shaft.
[AU, Nov / Dec – 2004, 2005]
2.84) A turbine shaft transmits 500 kW at 900 rpm. The permissible shear stress is 80
N/mm2
while twist is limited to 0.50
in a length of 2.5 m. Calculate the diameter of
the shaft. Take G = 0.8 x 105
N/mm2
. If the shaft chosen is hollow with di/d0 = 0.6,
calculate the percentage of saving in material. [AU, May / June – 2007]
2.85) A C45 steel shaft transmits 10 KW at 750 rpm. It is supported on two bearings
800 mm apart and has two gears keyed onto it. The pinion having 30 teeth of 5 mm
module is located 120 mm to the left of the right hand bearing and delivers power
horizontally to the right. The gear having 100 teeth of 5 mm module is located 150
mm to the right of the left hand bearing and receives power from below (CCW

viewed from the left to the end). Determine the diameter of the shaft.
[AU, Nov / Dec – 2001]
2.86) A horizontal nickel steel shaft rest on two bearings, A at the left and B at the right
end and carries two gears C and D located at the distance of 250mm and 400mm
respectively from the centre line of the left end and right bearings. The pitch diameter
of the gear C is 600mm and the gear D is 200mm. The distance between the center
line of the bearings is 2400mm. The shaft transmits 20kW at 120rpm. The power
delivered to the shaft at gear C and taken out at gear D in such a manner that the
tooth pressure FtC of the gear C and FtD act vertically downwards. Find the diameter
of the shaft, if the working stress is100MPa in tension and 56MPa in shear. The gear
C and D weighs 950N and 350N respectively. The combined shock and fatigue
factors for bending and torsion may be taken as 1.5 and 1.2 respectively.
[AU, Nov / Dec – 2012, May / Jun – 2016]
2.87) A transmission shaft is supported on two bearings which are 1m apart. Power is
supplied to the shaft by means of a flexible coupling, which is located to the left of
left hand bearing. Power is transmitted from the shaft by means of a belt pulley, 250
mm diameter, which is located at a distance of 300 mm from the left hand bearing.
The mass of the pulley is 20 kg and the ratio of belt tension on tight and slack sides
is 2:1. The belt tensions act vertically downward. The shaft is made of steel with
yield stress 300N/mm2
and the factor of safety is 3. Determine the shaft diameter, if
it transmits 10 kW power at 360 rpm from the coupling to the pulley
[AU, Nov / Dec – 2010]
2.88) A shaft supported at the ends in ball bearing carries a straight tooth spur gear at
its mid – span and is to transmit 7.5 KW at 300 rpm. The pitch circle diameter of the
gear is 150 mm. The distance between the center line of the bearing and gear are 100
mm each. If the shaft is made of steel and the allowable shear stress is 45 MPa,
determine the diameter. The pressure angle of the gear is 200
.
2.89) A shaft is supported by two bearings placed 1 m apart. A 600 mm diameter pulley
is mounted at a distance of 300 mm to the right of the left hand bearing and this drives
a pulley directly below it with the help of a belt having a maximum tension of 2.25
KN. Another pulley of 400 mm diameter is placed 200 mm to the left of the right
hand bearing and is driven with the help of an electric motor and belt, which is placed

horizontally to the right. The angle of contact for both the pulley is 1800
and =
0.24. Determine the suitable diameter for solid shaft; assume the working stress of
63 MPa in tension and 42 MPa in shear. Assume that the torque on one pulley is
equal to the other pulley. [AU, April / May – 2010, Nov / Dec – 2012]
2.90) A shaft is supported by two bearings placed l100 mm apart. A pulley of diameter
620 mm is keyed at 400 mm to the right of the left hand bearing and this drives a
pulley directly below it with a maximum tension of 2. 75 kN. Another pulley of
diameter 400 mm is placed 200 mm to the left of the right hand bearing and is driven
with a motor placed horizontally to the right. The angle of contact of the pulleys is
180° and the coefficient of friction between the belt and the pulleys is 0.3. Find the
diameter of, the shaft. Assume Kb = 3; Kt = 2.5, Syt = 190 MPa, Sut = 300 MPa
2.91) A mild steel shaft rotating at 720 rpm is supported between two bearings 80 cm
apart. It carries two pulleys A and B at a distance of 30 cm and 60 cm respectively
from the left bearing. 10 KW of power is fed into the pulley A with a diameter of 30
mm by vertical belt drives having the same ratio of driving tensions, which was
observed to be 2.5. Take t = 75 N/mm2
 = 45 N/mm2
. Design the diameter of the
shaft.
2.92) A steel solid shaft transmitting 15 KW at 200 rpm is supported on two bearings
750 mm apart and has two gears keyed to it. The pinion having 30 teeth of 5 mm
module is located 100 mm to the left of the right hand bearing and delivers power
horizontally to the right. The gear having 100 teeth of 5 mm module is located 150
mm to the right of the left hand bearing and receives power in the vertical direction.
Take  = 54 N/mm2
. Design the diameter of the shaft.
[AU, May / Jun – 2013, 2014, Nov / Dec – 2016]
2.93) A mild steel shaft transmits 20 KW at 200 rpm. It carries a central load of 900 N
and is simply supported between the bearings 2.5 m apart. Determine the size of the
shaft, if the allowable  = 42 MPa and the maximum tensile or compressive stress is
not to exceed 56 MPa. What size of the shaft will be required if it is subjected to a
gradually applied load? [AU, Nov / Dec - 2007]
2.94) A mild steel shaft transmits 23 KW at 200 rpm. It carries a central load of 900 N
and is simply supported between the bearings 2.5 m apart. Determine the size of the

shaft, if the allowable  = 42 MPa and the maximum tensile or compressive stress is
not to exceed 56 MPa. What size of the shaft will be required if it is subjected to a
gradually applied load? [AU, Nov / Dec - 2011]
2.95) Design a shaft to transmit power from an electric motor to a lathe head stock
through a pulley by means of a belt drive. The pulley weighs 200 N and is located
at 300 mm from the center of bearing. The diameter of the pulley is 200 m and the
maximum power transmitted is 1 KW at 120 rpm. The angle of lap of the belt is
1800
,  = 0.3. The shock and fatigue factor for bending and torsion are 1.5 and 2.0
Take  = 35 MPa.
2.96) A shaft carries pulley A at the left end and spur gear B at the middle of bearing
supports C and D. The pulley is 1000mm diameter and gear pitch diameter is 600mm.
The pulley is keyed to the shaft at 400mm to the left of the left hand bearing and the
distance between the bearing C and D is 1250mm. The shaft transmits 20Kw and
runs at 750rpm. The shaft receives power from a motor placed vertically below the
pulley through a flat belt with ratio of tension 2.5. The shaft delivers power to a gear
placed horizontally in front. The shaft rotates in ACW direction looking from left =
20.Design the shaft if the weight of A and B are 300N and 250N resp. Allowable
shear stress is 70N/mm2
.Shock and fatigue factor in bending and torsion are 2 and
1.5.
2.97) A solid steel shaft is supported on two bearings 1.8 m apart and rotates at 250
r.p.m. A 20° involute gear D, 300 mm diameter is keyed to the shaft at a distance of
150 mm to the left on the right hand bearing. Two pulleys B and C are located on the
shaft at distances of 600 mm and 1350 mm respectively to the right of the left hand
bearing. The diameters of the pulleys Band Care 750 mm and 600 mm respectively.
30 kW is supplied to the gear, out of which 18.75 kW is taken off at the pulley C and
11.25 kW from pulley B. The drive from B is vertically downward while from C the
drive is downward at an angle of 60° to the horizontal. In both cases the belt tension
ratio is 2 and the angle of lap is 180°. The combined fatigue and shock factors for
torsion and bending may be taken as 1.5 and 2 respectively. Design a suitable shaft
taking working stress to be 42 MPa in shear and 84 MPa in tension.
[AU, May / Jun – 2016]

2.98) An overhung shaft carries a 900 mm diameter pulley, whose centre is 250 mm
from the centre of the nearest bearing. The weight of the pulley is 600 N and the
angle of lap of the belt is 180°. The pulley is driven by a motor vertically below it.
If the permissible tension in the belt is 2600 N and coefficient of friction is 0.3,
determine the diameter of the shaft when internal diameter is 0.6 times the external
diameter. Neglect centrifugal tension and assume permissible shear and tensile
stresses as 64 N/mm2
and 84 N/mm2
. [AU, April / May – 2017]
2.99) A shaft is supported on bearings A and B, 800mm between their centers. A 20
straight tooth spur gear having 600mm pitch diameter is located 200mm to the right
of left hand bearing A and a 700mm diameter pulley is mounted 250mm towards the
left of bearing B. The gear is driven by a pinion with a downward tangential force
while the pulley drives a horizontal belt having 180 angle of wrap. Pulley weight is
2000N. The maximum belt tension is 3000N and tension ratio is 3:1. Determine the
max. B.M and diameter of shaft if allowable shear stress is 40N/mm2
2.100) A 600mm diameter pulley driven by a horizontal belt transmits power through a
solid shaft to a 262mm diameter pinion which drives a mating gear. The pulley
weights 1200N to provide some flywheel effect. The arrangements of elements, the
belt tension and the components of gear actions on the pinion are indicated in fig.
Determine the diameter of shaft Shock and fatigue factor in bending and torsion are
2 and 1.5. [AU, May / June – 2004]
2.101) The shaft of length 1 m carrying two pulleys 1 and 2 at its left and right ends
respectively and it is supported on two bearings A and B which are located 0.25 m
from the left end and the same 0.25 m from the right end respectively. The shaft
transmits 7.5 kW power at 360 rpm from pulley 1 to pulley 2. The diameters of pulley
1 and 2 are 250 and 500 mm respectively. The masses of pulley 1 and 2 are 10 kg
and 30 kg respectively. The belt tension act vertically downward and ratio of belt
tensions on tight side to slack side for each pulley is 2.5:1. The yield strength of the
shaft material σy= 380 MPa and factor of Safety is 3. Estimate the suitable diameter
of the shaft. [AU, Nov / Dec – 2015]
2.102) Compare the weight, strength and stiffness of a hollow shaft of the same external
diameter as that of solid shaft. The inside diameter of the hollow shaft being 0.6
times the external diameter. Both the shafts have same material and length.

2.103) A hollow shaft of 0.5 m outside diameter and 0.3 m inside diameter is used to
drive a propeller of a marine vessel. The shaft is mounted on bearings 6 metre apart
and it transmits 5600 kW at 150 r.p.m. The maximum axial propeller thrust is 500
kN and the shaft weighs 70 kN. Determine (i) The maximum shear stress developed
in the shaft, and (ii) The angular twist between the bearings. [AU, Nov / Dec – 2016]
2.104) A hoisting drum 0.5 m in diameter is keyed to a shaft which is supported in two
bearings and driven through a 12:1 reduction ratio by an electric motor. Determine
the power of the riving motor, if the maximum load of 8 KN is hoisted at a speed of
50m/min and the efficiency of the drive is 80%. Also determine the torque on the
drum shaft and the speed of the motor in r.p.m. Determine also the diameter of the
shaft made of machinery steel, the working stresses of which are 115 MPa in tension
and 50 MPa in shear. The drive gear whose diameter is 450 mm is mounted at the
end of the shaft such that it overhangs the nearest bearing by 150 mm. The combined
shock and fatigue factors for bending and torsion may be taken as 2 and 1.5
respectively [AU, April / May – 2011, Nov / Dec –2013]
2.105) In an axial flow rotary compressor, the shaft is subjected to a maximum twisting
moment of 1500 N-m and a maximum bending of 3000 N-m. Neglecting the axial
load on a shaft determine the diameter of the shaft, if the allowable shear stress is
50N/mm2. Assume Kb = 1.5 and Kt = 1.2. If the shaft is to be a hollow one with di
/ do = 0.4, what will be the material saving in the hollow shaft? It is subjected to the
same loading and of the same material as the solid shaft. Compare the torsional
stiffness of the two shafts. [AU, Nov / Dec –2014]
2.106) Hollow shafts, 0.5 m outside diameter and 0.3 m inside diameter is supported by
two bearings 6 m apart. The shaft is driven by a flexible coupling at one end and
drives a ships propeller at 100 rpm. The maximum thrust on the propeller is 500 kN,
when the shaft is transmitting 5000 KW. The shaft weighs 60 KN. Determine the
maximum shear stress induced in the shafts, considering the weight of the shafts and
column effects. Take shock and fatigue factors as Kt=1 and Kb=1.5.

2.107) The layout of a transmission shaft carrying two pulleys B and C and supported
by two bearings on bearings A and D as shown in fig. Power is supplied to the shaft
by means of a vertical belt on pulley B that is then transmitted to the pulley C
carrying a horizontal belt. The maximum tension in the belt on pulley B is 2.5KN.
The angle of wrap for both pulleys is 180◦
. The shaft is made of plain carbon steel
30C8 (σyt = 400N/mm2
) and FOS is 3. Determine the shaft diameter on strength basis.
2.108) A line shaft supporting two pulleys A and B is shown in figure. Power is supplied
to the shaft by means of a vertical belt on pulley A, which is then transmitted to
pulley B carrying a horizontal belt. The ratio of the belt tensions on the tight and
loose side is 3:1 and the maximum tension in either belt is limited to 2.7 KN. The
shaft is made of plain carbon steel 40C8 (σut = 650 N/mm2
) and σyt = 380 N/mm2
. The
pulleys are keyed to the shaft. Determine the shaft diameter according to the
A.S.M.E code if Kb =1.5 and Kt = 1.0.

2.109) Determine the lowest (i.e, first) critical speed for the shaft of 25mm diameter as
shown in figure.
2.110) Design a shaft to transmit power from an electric motor to a lathe head stock
through a pulley by means of a belt drive. The pulley weighs 200 N and is located at
300 mm from the centre of the bearing. The diameter of the pulley is 200 mm and
the maximum power transmitted is 1 kW at 120 rpm. The angle of lap of the belt is
180° and coefficient of friction between the belt and the pulley is 0.3. The shock arid
fatigue factors for bending and twisting are 1.5 and 2 respectively. The allowable
shear stress in the shaft may be taken as 35 MPa. [AU, Nov / Dec –2011]
2.111) It is required to design a square key for fixing a gear on a shaft of 30mm
diameter. The shaft is transmitting 20kW power at 600 rpm to the gear. The key is
made of steel 50C4 (Syt = 460 N/mm2
) and the factor of safety is 4. For the key
material, the yield strength in compression can be assumed to be equal to the yield
strength in tension. Determine the dimensions of the key. [AU, Apr / May – 2015]

2.112) Design a rectangular key for a shaft of 50mm diameter. The crushing and shear
stress of the key material are 70MPa and 42MPa.
2.113) Design a rectangular key for the following application: A shaft 65 mm diameter
transmits power at maximum shear stress of 67 MPa. The shear stress in the key
should not exceed 75% of the stress developed in the shaft. The key should be at
least 2.5 times strong m crushing compared to shear failure of the key.
2.114) Design a muff coupling to transmit a power of 35 KW from a shaft running at
120rpm. Assume suitable material and stresses.
2.115) Design a muff coupling to connect two shafts transmitting 40kW at 120rpm. The
permissible shear and crushing stress for the shaft and key material are 30MPa and
80MPa respectively. The material of muff is cast iron with permissible shear stress
of 15MPa. Assume that the maximum torque transmitted is 25% greater than the
mean torque. [AU, May / Jun - 2012]
2.116) Design a muff coupling to connect two shafts transmitting 40kW at 150rpm. The
permissible shear and crushing stress for the shaft and key material are 37MPa and
96.25MPa respectively. The material of muff is cast iron with permissible shear
stress of 1.75MPa. Assume that the maximum torque transmitted is 20% greater than
the mean torque. Take width and depth of the parallel key is 22mm and 14mm
respectively [AU, May / Jun - 2012]
2.117) Design a muff coupling to connect two steel shafts transmitting 25kW power at
360 rpm. The Shafts and key are made of plain carbon steel 30C8 (Syt = Syc = 400
N/mm2
). The sleeve is made of gray cast iron FG 200 (Sut = 200 N/mm2
). The factor
of safety for the shaft and key is 4. For the sleeve, the factor of safety is 6 based on
ultimate strength. [AU, Apr / May – 2015, May / Jun – 2016, 2017]
2.118) A rigid flange coupling is to be designed to transmit 20 KW at 1000 rpm.
Assuming suitable stress, design the coupling.
2.119) Design and make a neat dimensioned sketch of a muff coupling which is used to
connect two steel shafts transmitting 40 kW at 350 r.p.m. The material for the shafts
and key is plain carbon steel for which allowable shear and crushing stresses may be
taken as 40 MPa and 80 MPa respectively. The material for the muff is cast iron for

which the allowable shear stress may be assumed as 15 MPa.
[AU, April / May – 2011, Nov / Dec – 2016]
2.120) It is required to design a rigid type of flange coupling to connect two shafts. The
input shaft transmits 37.5 kW power at 180 rpm to the output shaft through the
coupling. The service factor for the application is 1.5, i.e. the design torque is 1.5
times of rated torque. Select suitable materials for various parts of the coupling,
design the coupling and specify the dimensions of its components.
[AU, Nov / Dec - 2009]
2.121) Determine the dimensions of flange coupling that connects a motor and a pump
shaft. The power to be transmitted a 2 kW at a shaft speed of 960 rpm. Select suitable
materials for the parts of the coupling and list the dimensions.
[AU, May / Jun – 2014]
2.122) Design a rigid type of flange coupling to connect two shafts. The input shaft
transmits 37.5 kW power at 180 rpm to the output shaft through the coupling. The
service factor for the application is 1.5. Select suitable material for various parts of
the coupling. [AU, Nov / Dec – 2010]
2.123) A rigid type of coupling is used to connect two shafts transmitting 15 kW at 200
rpm. The shaft, .keys and bolts are made of C45 steel and the coupling is of cast iron.
Design the coupling. [AU, May / Jun - 2013, Nov / Dec – 2016]
2.124) Design a rigid flange coupling to transmit a torque of 250 Nm between two co-
axial shafts. The shaft is made of alloy steel, flanges out of cast iron and bolts out of
steel. Four bolts are used to couple the flanges. The shafts are keyed to the flange
hub. The permissible stresses are given below:
Shear stress on shaft = 100 MPa
Bearing or crushing stress on shaft = 250 MPa
Shear stress on keys = 100 MPa
Bearing stress on keys = 250 MPa
Shearing stress on cast iron = 200 MPa
Shearing stress on bolts = 100MPa
After designing the various elements, make a neat sketch of the assembly indicating
the important dimensions. The stresses developed in the various members may be
checked if thumb rules are using for fixing the dimensions. [AU, Nov / Dec – 2013]

2.125) A rigid coupling is used to transmit 60kW power at 350rpm. There are 6 bolts.
The outer diameter of the flanges is 250mm, while the recess diameter is 175mm.
The coefficient of friction between the flanges is 0.15. The blots are made of steel
45C8 (Syt = 380 N/mm2
) and the factor of safety is 3. Determine the diameter of the
bolts. Assume that the bolts are fitted in large clearance holes.
[AU, Apr / May – 2015]
2.126) Design a cast iron protective flange coupling to transmit 15KW at 900rpm from
an electric motor to a compressor. The service factor may be assumed as 1.35. The
following permissible stress may be used:
Shear stress for the bolt and key material = 40MPa
Crushing stress for the bolt and key = 80MPa
Shear stress for cast iron = 8MPa
2.127) Design a cast iron flange coupling for a mild steel shaft transmitting 90 kW at
250 rpm. The allowable shear stress in the shaft is 40 MPa and the angle of twist is
not to exceed 1° in a length of 20 diameters. The allowable shear stress in the
coupling bolts is 30 MPa. [AU, Nov / Dec – 2007, 2011, 2014]
2.128) Design and draw a cast iron flange coupling for a mild steel shaft transmitting
90kW at 250 rpm. The allowable shear stress in the shaft is 40MPa and the angle of
twist is not to exceed 1º in a length of 20 diameters. The allowable shear stress in
coupling bolt is 30Mpa. [AU, Nov / Dec – 2012]
2.129) Design a protected type flange coupling for the following requirements. Power
to be transmitted= 10 kW. Speed of the shafts = 960 rpm. Select suitable materials
and suitable stresses [AU, Nov / Dec – 2015, April / May – 2017]
2.130) Design a bush type flexible flange coupling to transmit 10 KW at 720 rpm.
Allowable shear stress for shaft, key and bolt may be taken as 50 N/mm2
and the
crushing stress for the key as 110 N/mm2
. The permissible shear stress for the
coupling should be limited to 18 N/mm2
and the bearing pressure between the bush
and the coupling should be limited to 2 N/mm2
.
2.131) Design a bushed pin type of flexible coupling to connect a pump shaft to a motor
shaft transmitting 32kW at 960 rpm. The overall torque is 20% more than mean

torque. The material properties are as follows. The allowable shear and crushing
stress for shaft and key material is 40MPa and 80MPa respectively. The allowable
shear stress for cast iron is 15MPa. The allowable bearing pressure for rubber bush
is 0.8N/mm2
. The material of the pin is same as that of shaft and key. Draw a neat
sketch of the coupling. [AU, Nov / Dec – 2012, May / Jun – 2016]
2.132) Design a bushed pin type of flexible coupling for connecting a motor and a pump
shaft. The following data are provided: Power transmitted = 20 kW; Speed = 1000
rpm; Diameter of the motor and pump shafts = 50 mm; Allowable bearing pressure
in the rubber bush = 0.3 MPa. [AU, Nov / Dec – 2015]
2.133) Design a protective type of cast iron flange coupling for steel shaft transmitting
15 kW at 200 rpm and having an allowable shear stress of 40 N/mm2
. The working
stress in the bolt should not exceed 30 N/mm2
. Assume that the same material is used
for shaft and key that the crushing stress is twice the value of its shear stress. The
maximum torque is 25% greater than the full loaded torque. The shear stress for cast
iron is 14 N/mm2
. [AU, Nov / Dec – 2008, May / Jun – 2016]
2.134) Design a protected type flange coupling for the following requirements. Power
to be transmitted= 10 kW. Speed of the shafts = 960 rpm. Select suitable materials
and suitable stresses [AU, Nov / Dec – 2015]
2.135) Two 35 mm shafts are connected by a flanged coupling. The flanges are fitted
with 6 bolts on 25 mm bolt circle. The shafts transmit a torque of 800 N-m at 350
rpm. For the safe stresses mentioned below, calculate (i) diameter of bolts. (ii)
thickness of flanges, (iii) key dimensions (iv) hub length and (v) power transmitted.
Safe stress for shaft material 63 MPa, Safe stress for bolt material 56 MPa, Safe
stress for cast iron coupling 10 MPa and Safe stress for key material 46 MPa.
[AU, Nov / Dec –2011]
2.136) A flexible coupling is used to transmit 15 kW power at 100 rpm. There are six
pins and their pitch circle diameter is 200 mm. The effective length of bush, the gap
between two flanges and the length of the pin in contact with the right hand flange
are 35, 5 and 23 mm respectively. The permissible shear and bending stresses in the
pin are 35 and 152 N/mm2
respectively. Calculate the pin diameter by shear
consideration, bending consideration. [AU, May / June – 2007]

2.137) A power of 5 KW at 12 rps is transmitted through a flange coupling. Material
for bolt, shaft, and key and flange are C60, C40 and CI grade 30 respectively. Design
the coupling.
2.138) Design a taper key for a shaft of diameter 75 mm transmitting 45 kW at 225 rpm.
The allowable compressive stress as 160 N/mm2
. [AU, May / June – 2007]

UNIT – III – TEMPORARY AND PERMANENT JOINTS
PART – A
3.1) Define screwed joints. What are its basic elements?
3.2) Mention the advantages and disadvantages of screwed joints.
3.3) List the types of commonly used thread forms.
3.4) Name the common type of screw fastenings.
3.5) What is a stud? [AU, Nov / Dec - 2009]
3.6) Sketch a stud [AU, Nov / Dec - 2008]
3.7) What are the different applications of screwed fasteners? [AU, Nov / Dec – 2016]
3.8) What is the use of locking devices in screw fastening?
3.9) How is a bolt designated? Give examples. [AU, May / June – 2009]
3.10) What are the materials for bolts and screws [AU, April / May – 2011]
3.11) What is known as proof strength of the bolts? [AU, Apr / May – 2015]
3.12) What is preloading of bolts? [AU, Nov / Dec – 2015, 2016]
3.13) What is meant by single start and double start thread? [AU, Nov / Dec –2012]
3.14) What do you understand by the single start and double start threads?
[AU, Nov / Dec –2011]
3.15) Define the term self-locking of power screws.
[AU, Nov / Dec –2012, May / Jun - 2013]
3.16) State three conditions where tap bolt are used
3.17) Mention the types of locking devices.
3.18) What are the stresses induced in screwed fastening due to static loading?
[AU, May / Jun – 2016]
3.19) What is the total shear in a double strap butt joint with equal length of straps?
[AU, Nov / Dec – 2015]
3.20) Determine the safe tensile load for a bolt of M20, assuming a safe tensile stress
of 40 MPa. [AU, May / Jun - 2012]
3.21) Determine the safe tensile load for a bolt of M30, assuming a safe tensile stress
of 42 MPa.
3.22) What is threaded joint? [AU, April / May – 2010]
3.23) State the advantages of threaded joints. [AU, May / Jun - 2012]

3.24) What is the meaning of M14 * 2 threaded? [AU, April / May – 2010]
3.25) Why are ACME treads preferred over square thread for power screw?
[AU, Nov / Dec –2014]
3.26) List out the factors that influence the amount of initial tension.
[AU, May / Jun - 2012]
3.27) What is a gib? Why is it provided in a cotter joint
[AU, Nov / Dec –2013, May / Jun – 2016]
3.28) What is a cotter joint?
3.29) What is the purpose of cotter joint? [AU, April / May – 2010]
3.30) What are the applications of a cotter joint?
3.31) What are the types of cotter joints?
3.32) What are different types of cotter joints? [AU, May / Jun – 2014]
3.33) List the advantages of cotter joint over threaded joints. [AU, April / May – 2017]
3.34) What is meant by knuckle joint?
3.35) Where are knuckle joints used? [AU, April / May – 2011]
3.36) Distinguish between cotter and knuckle joints.
3.37) Mention the various methods of failure of knuckle joint.
3.38) Explain the purpose of turn buckle.
3.39) What is rivet? What are its types?
3.40) Give a few examples of detachable joints.
3.41) In what way temporary joint is better than permanent joint?
3.42) Give some examples for permanent and temporary joint.
3.43) What do you understand by the term riveted joint? Explain the necessity of such
a joint.
3.44) State any two advantages of welded joints over riveted joints.
3.45) How are plates riveted?
3.46) Classify the rivet heads according to IS specifications. [AU, Nov / Dec –2011]
3.47) List the four ways by which a riveted joint may fail. [AU, May / Jun - 2012]
3.48) What are the types of fit the diameter of a rivet hole and rivet will have?
3.49) Explain in what way are the riveted joints better than bolted joints.
3.50) Give the list of materials used in rivet manufacture.

3.51) Mention the applications of riveted joint.
3.52) Enumerate the different types of riveted joints and rivets.
3.53) Classify the types of rivet heads.
3.54) Sketch any four types of rivet heads, as recommended by B.I.S.
3.55) What is bearing failure in rivets? [AU, Apr / May – 2015]
3.56) What are caulking and fullering?
3.57) Name the possible modes of failure on riveted joint
[AU, Nov / Dec – 2008, 2012]
3.58) What are the different modes of failure of a riveted joint?
3.59) Explain the failure modes of riveted joints.
3.60) Define the efficiency of a riveted joint.
3.61) What are the assumptions made in designing the boiler joints?
3.62) Mention the assumptions made in riveted joint design. [AU, April / May – 2017]
3.63) According to I.B.R. what is the highest efficiency required for a riveted joint
3.64) Write the Uniwin's formula relating diameter of a rivet hole and thickness of the
plate.
3.65) What type of riveted joint is used in a pressure vessel?
3.66) What is meant by eccentric loading of a riveted joint?
3.67) Write any two advantages .and disadvantages of welded joints over riveted joints.
[AU, May / Jun - 2013]
3.68) Define welding. [AU, Nov / Dec - 2008]
3.69) What are the reasons of replacing riveted joint by welded joint in modern
equipment? [AU, Nov / Dec - 2010]
3.70) What is a welded joint?
3.71) Why are welded joints preferred over riveted joints? [AU, May / June – 2009]
3.72) What are the advantages of weld joints compared with riveted joints
3.73) What are the disadvantages of welding? [AU, Nov / Dec –2014]
3.74) State the advantages of the welded joints. [AU, Nov / Dec – 2015]
3.75) What are the two types of fillet weld? [AU, May / Jun – 2016]
3.76) Under what circumstances are welded joints employed?

3.77) Explain the merits and demerits of welded joint over riveted joint.
3.78) Why are welded joints preferred over riveted joints?
3.79) What are the different methods of welding?
3.80) Classify the welded joint with simple sketches.
3.81) What are two stresses induced in design the design of welding?
[AU, Nov / Dec –2012]
3.82) State the two types of eccentric welded connections.
[AU, Nov / Dec –2013, 2016, May / Jun – 2016]
3.83) What is throat thickness of a fillet weld?
3.84) Why throat is considered while calculating stresses in fillet welds?
3.85) Differentiate with a neat sketch the fillet welds subjected to parallel loading and
transverse loading. [AU, May / Jun – 2014]
3.86) Transverse fillet weld are preferred to parallel fillet welds. Why?
3.87) What is the minimum size for fillet weld? If the required weld size from strength
consideration is too small, how will you fulfill the condition of minimum weld size?
[AU, Nov / Dec – 2008]
3.88) Explain the representation of welded connections on drawings.
3.89) Write down the expression for strength of parallel fillet weld in terms of
permissible shear stress, leg of weld and length of welded joint.
[AU, Nov / Dec - 2009]
3.90) What is the bending stress induced in the weld when a circular rod of diameter d,
welded to a rigid plate by a circular fillet weld of size 't', which is subjected to a
bending moment M? [AU, Nov / Dec – 2015]
3.91) Write a short note on stress concentration in welds.
3.92) Explain eccentric loading of welded joints.
3.93) What is an eccentric loaded welded joint? Describe procedure for designing such
a joint. [AU, May / Jun – 2013, 2014]
3.94) What is the limitation of the single – strap butt joint?

PART - B
3.95) An electric motor weighing 5KN is to be lifted by an eye - bolt which has already
been crewed into it. Design the eye - bolt if the permissible stresses for the bolt
material are 60 MPa and 30 MPa and 80 MPa in tension, shear and crushing
respectively.
3.96) A mild steel cover plate is to designed for an inspection hole in the shell of a
pressure vessel. The hole is 120mm in diameter and the pressure inside the vessel is
6 N/mm2. Design the cover plate along with the bolts. Assume allowable tensile
stress for mild steel as 60MPa and for bolt material as 40MPa.
3.97) A steel bolt of M16x2 is 300mm long carries an impact load of 5000 Nm. If the
threads stop adjacent to the Nut and E = 2.1 x 105 MPa. (i) Find the stress in the root
area (ii) Find the stress if the shank area is reduced to root area.
[AU, Nov / Dec –2014]
3.98) ACME threads are used in a screw lever of a lathe. ACME threads have 50mm
outside diameter and 8mm pitch. The axial pressure required from the screw is
2500N. The collar subjected to thrust in the carriage is 110mm outside diameter and
55mm inside diameter and the load screw rotates at 30rpm. Determine (i) The power
required to drive the lead screw and (ii) The efficiency of the lead screw. Take µ for
the screw as 0.15 and that for collar as 0.12 [AU, April / May – 2010]
3.99) Determine the size of the bolts and the thickness of the arm for the bracket as
shown in figure. If it carries a load of 40KN at an angle of 60° to the vertical.
The material of the bracket and the bolts is same for which the safe stresses can be
assumed 70, 50, 105 MPa for tension, shear and compression respectively.
3.100) Figure shows a solid forged bracket to carry a vertical load of 13.5 kN applied
through the centre of hole. The square flange is secured to the flat side of a vertical
stanchion through four bolts. Estimate the tensile load on each top bolt and the

maximum shearing force on each bolt. Find the bolt size, if the permissible stress is
65 MPa in shear. All dimensions in mm. [AU, Nov / Dec –2016]
3.101) A mild steel cover plate is attached to a cast iron cylinder of 100 mm by means
of 6 studs placed at a radius of 150 mm. The maximum pressure inside the cylinder
is 400 N/mm2
. Design the diameter of the bolt and determine the amount of
prestressing required if the thickness of the cover is 15 mm. The material for the bolt
is C30 steel. The factor of safety is 2. Neglect the stiffness of gaskets. Calculate also
the tightening torque required.
3.102) A steam engine cylinder has a effective diameter of 350mm and the maximum
steam pressure acting on the cylinder cover is 1.25N/mm2
. Calculate the number and
size of studs required to fix the cylinder cover, assuming the permissible stress in the
studs as 33MPa. [AU, Nov / Dec - 2011]
3.103) Determine the size of bolts required to fasten the flanges of a rigid flange
coupling which is used to transmit a power of 20 KW at 1000 rpm. Assume the
allowable shear stress for the shaft and bolt material as 45 N/mm2
.
3.104) A flanged bearing is fastened to a frame by means of four bolts, spaced equally
on 500mm bolt circle. A 250 kN force acts at a distance of 200mm from the frame.
Flange diameter is 600mm. The tensile stress in the bolts is no to exceed 80N/mm2
.
Determine the size of the bolt. [AU, April / May – 2017]
3.105) A cast iron cylinder head is fastened to a cylinder of 500 mm bore with 8 stud
bolts. The maximum pressure inside the cylinder is 2 MPa. The stiffness of the part

is thrice of the bolt. What should be the initial tightening load so that the point is leak
proof at maximum pressure? Also choose a suitable bolt. 2
/300 mmNy  .
[AU, May / Jun – 2014]
3.106) A steam engine cylinder has an effective diameter of 350 mm and the maximum
steam pressure acting on the cylinder cover is 1.25 N/mm2
. Calculate the number
and the size of studs required to fix the cylinder cover. Assume the permissible stress
in the studs to be 70 N/mm2
. [AU, May / June – 2007]
3.107) A steam engine cylinder of 300 mm effective diameter, is subjected to a steam
pressure of 1.5 MPa. The cylinder head is connected by means of 8 bolts having yield
strength of 30 MPa and endurance limit of 240 MPa. The bolts are tightened with an
initial preload of 1.5 times that of steam load. A soft copper gasket is used to make
the joint leak proof assuming a fatigue stress concentration factor of 1.4, and factor
of safety of 2; determine the size of the bolts required. [AU, Nov / Dec – 2015]
3.108) For supporting the travelling crane in a workshop, the brackets are fixed on steel
column as shown in figure. The maximum load on the bracket is 12 KN acting
vertically at a distance of 400 mm from the face of the column. The vertical face of
the bracket is secured to a column by 4 bolts in each row, two at a distance of 50 mm
from the lower edge. Determine the size of the bolt if .84)( max MPat  Find the
cross section. [AU, Nov / Dec –2013]
3.109) A steel plate subjected to a force of 3 KN and fixed to a vertical channel by means
of four identical bolts as shown in figure. The bolts are made of plain carbon steel
45C8 (σyt = 380 N/mm2
) and the factor of safety is 2. Determine the nominal diameter
of the bolt.

3.110) The structural connection shown figure is subjected to an eccentric force P of 10
kN with an eccentricity of 500 mm. The center distance between bolts 1 and 2 is 200
mm and 1 and 3 is 150 mm. All the bolts are identical. Assume  = 80 N/mm2
for bolt
material. Design the size of the bolts. [AU, Nov / Dec – 2008]
3.111) A steel plate subjected to a force of 5 kN and fixed to a channel by means of
three identical bolts is shown in Fig. The bolts are made from plain carbon steel
45C8 and the factor of safety is 3. Specify the size of bolts. [AU, April / May – 2017]
3.112) A steam engine of effective diameter 300 mm is subjected to a steam pressure of
1.5 N/mm2
. The cylinder head is connected by 8 bolts having yield point 330 MPa
and endurance limit at 240 MPa. The bolts are tightened with an initial preload of

DESIGN OF MACHINE ELEMENTS QUESTION BANK

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