(a) Briefly explain the term metal fatigue and further explain how fatigue failure occurs.
(4)
(b) State the difference between high stress/low cycle and low stress/high cycle fatigue giving an example of each.
(4)
(c) State how defects in the metal can influence the expected safe life of a component.
(4)
(d) State how fuel injection timing and cylinder power balance can influence the possibility of fatigue cracks developing in the bedplate. (4
Reference Answer
### (a) Metal Fatigue and Fatigue Failure Mechanism **Definition of Metal Fatigue:** Metal fatigue is the progressive and localized structural damage that occurs when a material is subjected to fluctuating or cyclic stresses and strains. The critical feature of fatigue is that failure can occur at a stress level significantly lower than the material's Ultimate Tensile Strength (UTS) and often below its yield strength. It is a primary cause of failure in components subjected to vibration, rotation, or repeated loading cycles, such as crankshafts, connecting rods, and hull structures. **Mechanism of Fatigue Failure:**
Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.