r7310305-Design of Machine Members-i2

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1. (a) Discuss the factors to be considered in the selection of engineering materials. (Nov 2010)

(b) The crank pin of an engine sustains a maximum load of 35kN due to steam pressure. Ifthe allowable bearing pressure is 7MPa, find the dimensions of the pin. Assume length of

pin is 1.2 times diameter of pin. (Nov 2010)

2. (a) Differentiate between endurance limit and endurance strength. (Nov 2010)

(b) Determine the diameter of a circular rod made of ductile material with fatigue strengthof 280 MPa and yield strength of 350MPa. The member is subjected to a varying axial

load from 700kN to-300kN. Assume Kt =1.8 and FS=2.0(Nov 2010)

3. Design a double riveted butt joint with two cover plates, for the longitudinal seam of a boilershell 1.5m diameter subjected to a steam pressure of 0.9MPa. Assume the joint efficiency as

75%, allowable tensile stress in plate 90MPa, compressive stress 140MPa; and shear stress inthe rivets is 56 MPa. (Nov 2010)

4. (a) Explain design of bolted joints with combined pre-load and external loads. (Nov 2010)

(b) A steam engine cylinder has an effective diameter of 350mm and maximum steam pressureis 1.25 MPa. Calculate the member and size of studs required to fix the cylinder cover

assuming permissible stress in the studs as 33MPa. (Nov 2010)

5. Design a spigot and socket type cotter joint to carry a load of 25kN. The stress induced islimited to 50MPa in tension; 35MPa in shear and 90MPa in crushing. (Nov 2010)

6. Design a muff coupling to connect two shafts to transmit 40KW at 350 RPM. The shear stressand crushing stress for the shaft and key material are 40MPa and 80MPa respectively. The

material for the muff is cast iron for which shear stress is limited to 15 MPa. (Nov 2010)

7. Find the diameter of a solid steal shaft to transmit 20KW at 200RPM. The ultimate shearstress for the steel may be taken as 360MPa and a factor of safety of 8. If a hollow shaft is

used in place of solid shaft find the inside and outside diameters if their ratio is 0.6(Nov 2010)

8. Describe the design of helical compression springs.(Nov 2010)


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8. Describe the design procedure of leaf springs.(Nov 2010)


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1. (a) Enlist the manufacturing considerations in design of machine members. (Nov 2010)

(b) The diameter of a piston of steam engine is 300mm and the maximum permissible steampressure is 0.7MPa. If the maximum permissible compressive stress for the piston rod

material is 40MPa, find the size of the piston rod. (Nov 2010)

2. (a) Illustrate the methods of reducing stress concentration. (Nov 2010)

(b) A simply supported shaft between bearings carries a load at 15KN at the centre. Thespan of beam is 500mm. The load varies to a maximum value of 30KN. Find the diameterof the shaft if its endurance limit is 600MPa and surface factor is 0.88, size factor is 0.8

and FS=1.6. (Nov 2010)

3. Design the longitudinal joint for a 1.25m diameter steam boiler to carry a steam pressure of2.5 N/mm2 . The ultimate strength of the boiler plate may be assumed as 420MPa, crushing

strength as 650MPa and shear strength of 300MPa. The joint efficiency as 80%. The FOS=2.0. (Nov2010)

4. (a) Enumerate various types of locking devices, seals and thread forms. (Nov 2010)

(b) The cylinder head of a steam engine is subjected to 1.0MPa. It is held in position bymeans of 12 studs. The effective diameter is 300mm. A soft copper gasket is used to makejoint leak proof. Determine the size of the bolts or studs, so that bolt stress should not

exceed 100MPa. (Nov 2010)

5. Design a Gib and Cotter joint to carry a pull of 35KN. The stress in the materials are limitedto 20MPa in tension; 15MPa in shear; and 30MPa in crushing. (Nov 2010)

6. Design a split muff coupling to transmit 25KW at 200 RPM. The allowable shear stress for theshaft and key is 40MPa and number of bolts connecting two halves are six. The permissibletensile stress for the bolts is 70MPa. The coefficient of friction between the muff and shaft

surface is 0.3. (Nov 2010)


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7. A line shaft is driven by means of a motor placed vertically below it. The pulley on the lineshaft is 1.5 metre in diameter and has belt tensions 5.8 KN and 1.2 KN on the tight side andslack side of the belt respectively. Both these tensions may be assumed vertical. The pully isoverhang on a shaft with a distance of 500mm. Find the diameter of shaft. The shear stress is

limited to 42MPa. (Nov 2010)

8. Describe the design of helical springs subjected to fatigue loading.(Nov 2010)


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1. (a) What are the factors to be considered in determination of factor of safety?(b) Find the minimum size of the hole that can be punched in a 20mm thick steel plate, having

an ultimate tensile strength of 600MPa. The maximum permissible compressive stress inthe punch material is 1200MPa. Assume ultimate shear strength of plate material is half

its ultimate tensile strength. (Nov 2010)

2. (a) What are the various factors influencing endurance strength.(b) Find the diameter of a shaft to transmit twisting moments varying from 800 Nm to

1600Nm. The ultimate tensile strength for the material is 600MPa, and yield stress is400MPa. Assume the stress concentration factor=1.2; surface finish factor =0.8 and size

factor =0.85. (Nov 2010)

3. Two plates of 8mm thickness each are to be joined by a single riveted double strap butt joint.Design the joint with working stresses in tension and shearing and compression are 80MPa,

60MPa and 100MPa respectively. (Nov 2010)

4. (a) Explain what are bolts of uniform strength.(b) The cylinder head of a steam engine is subjected to a steam pressure of 0.7MPa. It is held

in position by 12 studs. A soft copper gasket is used to make the joint leak proof. Theeffective diameter of cylinder is 300mm. Find the size of the bolts, so that the stress is

limited to 100MPa. (Nov 2010)

5. Design a Gib and Cotter joint with two gibs to carry a load 30KN. All the components aremade of same material with limiting stresses in tension 20MPa; in shear 15MPa and in crushing

30MPa. (Nov 2010)

6. Design a protective type flange coupling for C.I. flange to connect two steel shafts to transmit

15KW at 200RPM, with shear stress limited to 40MPa for steel. The working stress in thebolts not to exceed 30MPa. Assume that the same material is used for key, shaft and bolts andthe crushing stress is twice shear stress. The maximum torque is 25% greater than full torque.

The shear stress for cast iron is 14MPa. (Nov 2010)

7. A hollow shaft with 0.8 and 0.6m as diameters, transmits 5000 KW at 200 RPM. The shaftis mounted on bearings 6 metre apart. The thrust on shaft is 500KN and shaft weighs 70KN.

Determine maximum shear stress in the shaft and angular twist between bearings. (Nov 2010)


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8. Describe the design procedure of composite co-axial springs. (Nov 2010)

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r7310305-Design of Machine Members-i2