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ANNA UNIVERSITY COIMBATORE E IB.TECH DEGREE EXAMINATIONS:
DECEMBER 2009
REGULATIONS : 2007FIFTH SEMESTER
070120059 - DESIGN OF MACHINE ELEMENTSCOMMON TO MECHANICAL
METALLURGICAL ENGG.
TIME: Hours Max.Marks: 100PART-A
20 x 2 40 MARKSANSWER ALL QUESTIONS
1) What are the factors that inf luence the factor of Safety?2)
State the different failure theories and the type of materials for
which these areapplicable
3) Define the morphology of design.4) What is stress intensity
factor?5) How hollow shafts are superior to solid ones.6) In what
situations, flexible coupl ings are used.7) What kind of loading is
permissible to a knuckle joint?8) What are the difference between a
coupling and a clutch?9) What is meant by a self locking screw?10)
What are the advantages of riveting over welding?11) What are the
assumptions made in the design of welded joint?12) Define the
theory of bonded joints.13) Define free length ofa spr ing.14) What
isthe function of a spr ing?15) Define resil ience of a spr ing.16)
What is surge in springs and how to eliminate it?17) Sketch the
distr ibution of pressure in the circumferential and axial direct
ions ina
hydrodynamic journal bearing.
18) State the merits of hydrostatic bearings.19) Name the type
of lubricant used in journal bearing.20) Name the type of stresses
induced in flywheel.
PART-B5 x 12 60 MARKS
ANSWER ANY FIVE QUESTIONS
21) A hub is press f it ted on a shaft. An element in the hub
issubjected to aradial compressive stress (pressure) of 50MPa and
hoop stress of75MPa. Find the factor of safety if a) hub is made of
C45 steel. Usingmaximum shear stress theory b) if the hub is made
of cast iron.
22) A cast iron shaft with an ultimate tensile strength of 175
MPa, is subjectedto a tor sional load which is completely reversed,
the load is to be appliedan indefinite number of cycles, the shaft
is 50mm diameter and is joinedto a 75mm diameter shaft with a
12.5mm radius fillet. The factor of safetyis to be 2. What is the
maximum torque that can be applied to the shaft?Solve using
Soderbergs equation.
23) A cold drawn steel rod of circular cross sect ion is
subjected to a variablebending moment of 600 to 1200 NM as the
axial load var ies from 5000to 14000N. The maximum bending moment
occurs at the same instantthat the axial load is maximum. Determine
the required diameter of therod for a factor of safety of 2.
Neglect any stress concentration andcolumn effect. Design on the
basis of the maximum shear stress.
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24) Design a rigid muff coupling. The power transmitted is 30 KW
at 360 rpm.Factor of safety is 6. Use C45 for the shaf t. Assume
other data ifrequired.
25) A plate 90mm wide and 15mm thick isjoined with another p la
te byasingle transverse weld and a double par allel fillet weld.
Determine thelength of par allel fillet, i f the join t is
subjected to both s tati c and fatigueloading, taking tensile
stress as 70 MN / m2and compressive stress as56 MN / m2Stress
concentration factor may be taken as 1.5 for transverseweld and 3.7
for parallel fillet weld.
26) Design a coil spring to carry a load of 500N with an
allowable deflection of25mm. The spring index may be taken as 6.
Suitable material may beassumed with a factor of safety 3.
27) Select a single row deep groove ball bearing to operate on
the followingwork cycle. A rated life of 3000 hours is desired.
a. Radial load of 5kN at 500 rpm for 25 of time.b. Radial load
of 10kN and an axial load of 2kN at 700 rpm for 50 of time.c.
Radial load of 7kN at 400 r pm for the r emaining 25 of time.
28) A single cyl inder double acting steam engine deliver s 185
kW at 100 rpm.The maximum f luctuation of energy per revolut ion is
15 of energydeveloped per revolution. The speed var ia tion is l
imited to 1 either wayf rom the mean. The mean diameter of the rim
is 2.4m. Design a cast i ronflywheel for the engine.
THE END
