DEPARTMENT OF MECHANICAL ENGINEERING DESIGN OF MACHINE ELEMENTS
PART A
UNIT-1
1. Name atleast five mechanical properties of materials .
2. What are factors to be considered for the selection
of materials for the design
of machine elements(
3. Define factor of safety
for ductile and brittle materials
4. Explain preferred number with an examples(
5. What is free cutting
steel? How it is designated?
6. How engineering materials are classified
7. Write composition designated
as given below XT 15 Cr 16 Ni 2(Apr 10
Unit-2
1. What are the types of shaft?
2. What are the advantages and disadvantages of keys?
3.
What are keys? How are they classified?
4. What are the requirements of couplings?
5.
Name three types of couplings used in engineering
Unit-3
1.What are the requirements of belt drive
2.Explain the two different belt drives with sketches 3.Explain different types of belts with sketches.
4.Explain different types of belts material. 5.compare flat belt with v-belt
1. How bearings are classified?
Unit-4
2. Write short notes on radial and thrust ball bearing
3. Explain how ball bearing
is designated with an example
4. Explain the important physical
characteristics of a good bearing material
5. State the advantage of roller contact bearings
Unit-5
1.
What is CAD?
2. What are the benefits of CAD?
3.
What are the disadvantages of CAD?
4.
What are the applications of CAD?
5.
State the various activities of
6. Compare sequential engineering and concurrent engineering.
7.
What are the benefits/advantages of concurrent engineering
8. Define transformation?
9. What are the techniques of geometric
modeling?
10.
What are the advantages and disadvantages of solid modeling?
11. What are the advantage
of wire frame modeling
12. What are the advantage of surface modeling.
13. What is finite element
analysis
14. State any four advantages of finite element
analysis?
PART B
UNIT-1
1. Design
sleeve and cotter joint to transmit a tensile load of 60kN, Assuming that all
the parts are made of same material.
The permissible stresses
are 60N/mm^2 in tension, 120N/mm^2
in Crushing and 75N/mm^2 in shear.
2. Design a
Sleeve and cotter joint to transmit a tensile load of 80kN, Assuming the all
part are made of same material
the permissible stresses
are 62N/mm^2 in tension,125 N/mm^2 in bearing and 78 N/mm^2 in shear.
3. Design a
sleeve and cotter joint to withstand a tensile load of 70kN.All parts are made
of same materials. The permissible stresses are 60N/mm^2
in tension,120N/mm^2 in compression and 70N/mm^2 in shear.
4. Design a
sleeve and cotter joint to withstand a tensile load of 60kN. All parts are made
of same materials and the permissible stresses
in the material are 60N/mm^2
in tension, 125N/mm^2 in crushing and 70N/mm^2 in shear.
5. Design a
knuckle joint to sustain a maximum pull of 80kN.The working stresses of rod
material are 75MPa in tension and 70MPa in shear. The permissible shear stress for the pin material is 65MPa.
6. Design a
knuckle joint to take a load of 60kN, assuming that all parts are made of same
material. The permissible stresses
are 60MPa in tension and 75MPa in compression and 40MPa in shear respectively,
7. Design a
sleeve and cotter joint to withstand a tensile load of 70kN, all parts of the
joint are made of same material. The
permissible stresses are in 60N/mm^2 in tension, 120N/mm^2 in compression, and 70N/mm^2
in shear.
8. Design a
knuckle joint to take load of 140kN, for the following permissible stress:
75MPa in tension, 140MPa in compression, and 65MPa in shear.
9. Name the type of steel with
its composition designated as X15Cr16 Ni12 or XT15CrNi2
10. What are the factors
to be considered for the selection of materials for the design of machine
elements?
11. Define factor of safety for ductile and brittle materials’.
12. A Knuckle
joint connects two parts of a tie – rod subjected to an axial load of 100 KN. The Ultimate
stresses for the material of the joint are 480 N/mm2 in tension and 360 N/mm2 in shear .Design
the Joint.
UNIT-2
13. Design the give the complete
specification of a protected type flange coupling to transmit a power of 15KW at 240Rpm.The Permissible shear
stress for the shaft, bolt and key materials is 35N/mm2, The permissible crushing stress for the bolt
and key materials is 60N/mm2 and the permissible shear stress for the flange materials
is 15N/mm2.Assume that the maximum torque
exceeds the mean torque
by 20%.
14. Design a
protective type flange coupling to connect two shafts to transmit 7.5KW at 720
Rpm. The Permissible shear stress for
shafts, bolt and key materials is
33N/mm2, Permissible crushing strength for the
bolt and key materials of 60N/mm2 and permissible
shear stress for CI is 15N/mm2.
15. Design a protective type of
cast iron flange coupling for a steel shaft transmitting 15KW at 200Rpm. The allowable shear stress is 40N/mm2. The
working stress in the bolts should not exceed 30N/mm2. Assume that the same material is used for shaft and key. The
crushing stress is twice the value of shear stress. The maximum torque is 25% greater than full load torque. The shear stress for cast iron
is 14N/mm2. Check your design for Hub, Key, Flange and
Bolts.
16. A rigid flange coupling is
to be designed to transmit 20KW at 1000rpm. Allowable shear stress for shaft, key and bolts is 40N/mm2. Allowable
crushing stress for key and bolts is 80N/mm2, and Allowable shear stress for flange material
is 15N/mm2. Design the coupling
17. The shaft
and flange of marine coupling is to be transmitting 3MW at 100 rpm. The shear stress for shaft and bolts is 60N/mm2. The number of bolt is 8. The P. C. D of the bolt is 1.6d. Design the coupling.
UNIT-3
17. The following data refers to
a V-belt drive; Power to be transmitted-75KW; Speed of driving wheel- 1440rpm;Speed of driven
wheel-400rpm;Diameter of driving wheel-300rpm;Center distance-2.5m;Smaller pulley factor-1.07;Service factor-1.3;Correction
factor for length-1.07.Design and give the complete details of the drive.
18. Design V-belt drive for the
following specifications; Power to be transmitted- 75KW, Speed of driving wheel - 1440rpm, Speed of driven wheel -
400rpm, Diameter of driving wheel - 300mm,Center distance - 2500mm, Small pulley factor, kd - 1.14, Service factor, ks -1.3,Correction factor for length kl - 1.07
19. Design a V-belt drive using manufacture’s data to the following specifications; Power to be transmitted;75KW;Speed
of driving pulley;1000rpm;Speed of driven pulley - 300rpm;Diameter of driving pulley - 150mm;Diameter of driven pulley -
500mm;Center distance between pulleys - 925mm;Service -16 hrs/day.
20. Design a V-belt drive using manufactures data to the following specifications: Power to be transmitted=75KW;
Speed of driving wheel=1440rpm; Speed of driven =400rpm; Diameter of driven wheel=300mm; Center distance
=2500mm; Service =16hrs/day.
21. Design a
V-belt drive to transmit 15KW to a compressor. The Motor Speed is 1200RPM and
the Compressor Pulley runs at 400RPM. Determine the size and numbers of belts.
22. Design a V-belt drive on Manufacturer’s data to the following Specifications;
Diameter of driven Pulley = 600mm, Diameter of driving Pulley = 200mm, Center distance between Pulleys = 1000mm (approx.),Speed of driven Pulley = 400 rpm ,Speed of driving Pulley = 1200 rpm
,Power transmitted 10KW ,Service –heavy duty = 16 hrs/day.
UNIT-4
23. Design a
suitable journal bearing for a centrifugal pump having a following
specifications: Load on bearing-13.25kN; Diameter
of the journal-80mm; Speed-1440 Rpm; Permissible bearing
pressure-0.7 to
1.4 N/mm^2; Ambient temperature-30oC. L/D Ratio-1.6 ; Average temperature of oil-75oC (SAE 40) ; K -
0.273 for heavy construction and well ventilated bearings and ; temp rise -8 oC. Specific heat of oil = 1710 J/Kg o C . Calculate the cooling requirements.
24. Design a
suitable journal bearing for a centrifugal pump having a following
specifications: Load on bearing-14kN;
Diameter of the journal-80mm; Speed-1440rpm; Bearing characteristic
number-30x10^-6 ; Permissible bearing
pressure-0.7 to 1.4N/mm^2; Average atmospheric temperature-30*c L/D ratio-2; average temperature of oil-75*c;
coefficient of heat dissipation-0.273W/m^2/*c; temp rise -6*c. Calculate the cooling requirements using laches `equations and McKee’s equation
for calculating friction
Co efficient.
25. Design a
Suitable journal bearing for a centrifugal pump to withstand a load of 60kN.the
diameter and the speed of the
journal are 150mm and 960 rpm respectively.
26. Design a Journal bearing for
a centrifugal pump from the following data: Load on the journal = 20kN, speed = 900rpm, type of oil used is SAE10
for which the absolute viscosity at 55oc=17centipoise, ambient temp of oil=15.5oc, Max bearing pressure
=1.5N/mm^2 .Heat dissipation co efficient =1232 J/s/m^2/oC. Calculate
mass of lubricating oil required for artificial cooling,
rise of temp of oil is limited
to 10o .
27. Journal
bearing is proposed for a centrifugal pump. The diameter of the journal is
150mm and the load on its 40kN
and its speed is 900rpm
.design and give the complete calculation of the
bearing.
29. Design a Journal bearing
for a centrifugal pump from the following data:
Load on the journal= 20kN,
Speed = 900rpm
Type of oil used SAE10 Absolute viscosity at 55*c=17cP Amp ion temp of oil=15.5*c Max bearing Press =1.5N/mm^2
Heat dissipation Co Efficient =1232 J/s/m^2/*c Calculate mass o lubricating oil required for Artificial cooling, if rise of temp of oil is limited to 10*c .
30. A Journal bearing 75mm long
support a load of 7.5kN and the 50mm diameter. Journal running at 750rpm the diameter clearance is 0.0693mm.
Determine the viscosity of oil if operating temp of bearing surface is
limited to 77oC, Ambient temperature is 21oc heat dissipating co efficient is 210W /m^2/oc
.
31. In a journal
bearing diameter of the shaft is 75 mm , L/D = 1 , Radial Clearance = 0.05 mm,
Minimum film thickness = 0.002mm ,Speed of journal = 400 Rpm ,Radial Load = 3.5 KN , Specific gravity
of oil =
0.9 , Specific heat of oil = 1.75 KJ/kgoC .Calculate the viscosity of suitable oil, Power lost in friction and resultant temperature rise.
UNIT-5
1.
Explain product development cycle.
2. Explain the Shigley’s design
process.
3.
Explain the Pahl and Beitz model.
4. Explain the sequential engineering.
5.
Explain the concurrent engineering.
6. Explain the 2D transformations with example.
7. Explain the 3D transformations with example.
8. Explain the w i r e f r a m e modeling.
9.
Explain the surface
modeling techniques.
10. Explain the solid modeling
techniques.
11. Compare wireframe model, surface model and solid
model.
12. Explain the basic steps of FEA.
