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1. What do you meant by endurance strength of a material? How do thesize and surface condition of a component and type of load effect such

strength?

2.

A 45mm diameter shaft is made of steel with a-yield strength of40N/mm2. A parallel key of size 14 mm wide and 9 mm thick made of

steel with a yield strength of 34 N/mm2

is to be used. Find the required

length of key, if the shaft is loaded to transmit the maximum

permissible torque. Use maximum shear stress theory and assume a

factor of safety of 2.

3. Clearly define the term stress concentration factor giving at least oneexample.

4. List the important factors that influence the magnitude of factor ofsafety.

5. Discuss in detail the design procedure of a spigot and socket cotterjoint.

6. List various design consideration and explain any two.7. Explain the mechanism of fatigue failure. Why it is considered to be

dangerous?

8. The piston rod of a steam is 50mm in diameter and 600mnn long. Thediameter of the piston is 400mm and the maximum steam pressure is

0.9MPa. Find the compression of the piston rod, if the Young's modulus

for the material of the piston rod is 210 GPa.

9. Design a sleeve and cotter joint to resist a tensile load of 40 kN. Thematerial of the cotter is Fe330. Take a factor of safety of 4 for each

Allowable crushing stress c = 1.4 t (tensile stress)

Allowable shearing stress = 0.8 t (tensile stress) for all threecomponents.

10. A steam engine cylinder has an effective diameter of 350mm andmaximum steam pressure acting on the cylinder cover is 1.25 MPa.

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Calculate the no. and size of studs required to fix the cylinder cover,

assuming the permissible stress in the studs as 33MPa.

11. What is meant by stress concentration? Illustrate how the stressconcentration in machine components can be reduced.12. How would you differentiate between ductile, brittle and fatiguefailures? State the factors to be considered while designing to avoid

fatigue failure.13. A circular cross-section steel part is subjected to a torsional load that

varies from +36 kN-cm to -12 kN-cm and a bending load that varies

from +48 kN-cm to -24 kN-cm. the ultimate strength of material is 560

N/mm2 and yield strength suitable values of type of loading factor, size

factor and surface finish factor. A minimum factor of safety of 1.5 may

be used in soderberg equation.14. Differentiate between strength, stiffness and rigidity considerations of

design. What are the parameters on which stiffness and rigidity of a

machine part depends?

15. Design and draw a neat sketch (two views) of a cotter joint to connecttwo mild steel rods to transmit an axial load of 30 kN.

16. What do you mean by fatigue failure? Why it is o dangerous?17. What is factor of safety? Why it is sometimes called factor of

ignorance?

18. Design of a cotter joint to connect piston rod to