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Q9. A. Briefly explain the term fatigue and explain how fatigue failure occur;

B. State the difference between high stress / low cycle and low stress / high cycle fatigue giving an example of each;

C. State how defect in metal can influence the expected safe life of a component;

D. State how fuel injection timing and cylinder power balance can influence the possibility of fatigue cracks developing in the bedplate.

Q2.  Describe TWO methods of tracing a superficial crack in a marine machinery component; Explain the procedure for arresting propagation of a crack in a machinery component.

Q5. Describe briefly the methods of carrying out a bend test and an impact test. Illustrate the general form of the test pieces used and state how the final results are given for comparison of different materials. Of what practical use are the figures obtained? (16)

Q5: With reference to fatigue of engineering components explain the influence of stress level and cyclical frequency on expected operating life;

A. Explain the influence of material defects on the safe operating life of an engineering component;

B. State the factors which influence the possibility of fatigue cracking of a bed-plate transverse girder and explain how the risk of such cracking can be minimized.

Q6. a) Describe Three methods of tracing a superficial crack in a marine machinery component;

b) Explain how propagation of a crack in a machinery component can be arrested.

Describe TWO methods of tracing a superficial crack in a marine machinery component;

Q2. Describe the following properties of steel and which components are most considered with advantages & disadvantages.

a) Ductility (4)

b) hardness (4)

c) Malleability (4)

d) Toughness (4)

Q7. Write short notes on the following:

(a) Ultrasonic testing (8)

(b) Shaft earthing device (8)

Q6. Describe the following metallurgical tests and explain why EACH is carried out:

(a) Impact test (4)

(b) Hardness test (4)

(c) Endurance test (4)

(d) Tensile test (4)