Hall Ticket No Question Paper Code: AME012
INSTITUTE OF AERONAUTICAL ENGINEERING
(Autonomous)
Four Year B.Tech V Semester End Examinations (Regular) November, 2018
Regulation: IARE R16
DESIGN OF MACHINE MEMBERS
Time: 3 Hours Max Marks: 70
Answer ONE Question from each Unit
All Questions Carry Equal Marks
All parts of the question must be answered in one place only
UNIT I
1. Explain the basic procedure of machine design.
Discuss the various mechanical properties of engineering materials.
2. Discuss the various methods for the reduction of the stress concentration.
A forged steel bar,50 mm in diameter, is subjected to a reversed bending stress of 250 N/mm2.The
bar is made of steel 40C8(sut =600 N/mm2).Calculate the life of the bar for a reliability of 90%.
Take ka=0.55, kb=0.85, kc=0.897.
UNIT II
3. Explain basic types of screw fastening.
A double riveted lap joint is made between 15 mm thick plates. The rivet diameter and pitch
are 25mm and 75 mm respectively. If the ultimate stresses are 400 MPa in tension, 320 MPa in
shear and 640 MPa in crushing, find the minimum force per pitch which will rupture the joint.
If the above joint is subjected to a load such that the factor of safety is find out the actual
stresses developed in the plates and the rivets.
4. List out Advantages and Disadvantages of Welded Joints over Riveted Joints
A steel plate, 100 mm wide and 10 mm thick, is joined with another steel plate by means of single
transverse and double parallel fillet welds, as shown in Figure 1. The strength of the welded joint
should be equal to the strength of the plates to be joined. The permissible tensile and shear
stresses for the weld material and the plates are 70 and 50 N/mm2 respectively. Find the length
of each parallel fillet weld. Assume the tensile force acting on the plates as static.
Figure 1
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UNIT III
5. Explain the different types of keys with neat sketches.
Design the rectangular key for a shaft of 50 mm diameter. The shearing and Crushing stresses
for the key material are 42 MPa and 70 MPa.
6. What is Knuckle joint? Write the design procedure for the Knuckle joint.
Design a sleeve and cotter joint to resist a tensile load of 60 kN. All parts of the joint are made
of the same material with the following allowable stresses 60 MPa 70 MPa and
125 MPa
UNIT IV
7. A shaft transmitting a maximum torque of 800 N-m is also subjected to a maximum bending
moment of 1050 N-m.The transmission involves moderate shocks.The Permissible shear stress for
the shaft material is given as 48 N/mm2. Determine the diameter of the shaft required for the
purpose by using ASME code.
A propeller shaft is required to transmit 45 kW power at 500 rpm.It is a hollow shaft,having
inside diameter 0.6 times of outside diameter.It is made of plain carbon steel and the permissible
shear stress is 84 N/mm2.Calculate the inside and outside diameters of the shaft.
8. List out why couplings are used and what are the basic requirements for it.
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.
UNIT V
9. Explain the different types of springs with neat sketches.
A safety valve of 60 mm diameter is to blow off at a pressure of 1.2 N/mm2.It is held in its seat by a
close coiled helical spring. The maximum lift of the valve is 10 mm. Design a suitable compression
spring of spring index 5 and providing an initial compression of 35 mm. The maximum shear
stress in the material of the wire is limited to 500 MPa. The modulus of rigidity for the spring
material is 80 kN/mm2. Calculate:
i.Diameter of the spring wire
ii.Mean coil diameter
iii.Number of active turns and
iv.Pitch of the coil.
Take Wahl's factor 4C-1/4C-4+0.615/C, where C is the spring index.
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10. Define the terms solid length, spring index, spring rate, free length and pitch of the coil related
to helical compression springs.
A helical compression spring of a cam-mechanism is subjected to an initial pre load of 50 N.The
maximum operating force during the load cycle is 150 N.The wire diameter is 3 mm, while the
mean coil diameter is 18 mm.The spring is made of oil-hardened and tempered valve spring wire
of Grade-VW(sut =1430 N/mm2).Determine the factor of safety used in the design on the basis
of fluctuating stresses. Take sse'=0.22 Sut; Ssy 0.45 Sut