Class 2 (2nd Engineer) MEKG 📅 Dec 2024

Exam Question

(a) With reference to fatigue of engineering components explain the influence of stress level and cyclical frequency on expected operating life.

(b) Explain the influence of material defects on the safe operating life of an engineering component.

(c) 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.

Reference Answer

### (a) Influence of Stress Level and Cyclical Frequency on Fatigue Life
Fatigue is a failure mechanism that occurs in materials subjected to dynamic and fluctuating stresses. Failure can occur at a stress level significantly lower than the material's ultimate tensile strength (UTS) or yield strength under a static load. The process involves the initiation and propagation of a crack until the remaining cross-section can no longer support the applied load, leading to sudden fracture.
**1. Influence of Stress Level (Stress Amplitude):**
The magnitude of the cyclic stress is the most critical factor determining the fatigue life of a component. This relationship is graphically represented by the **S-N Curve (Stress vs. Number of cycles to failure)**.

Full answer on MeoMock — surveyor-grade reference answers for 7,000+ written exam questions.

View plans Browse library

← Browse more questions

Prepare on Android — MeoMock on Google Play