With reference to a ball race bearing, what does the term "brinelling" refer to?
A) Permanent deformation of the raceway surface due to excessive load, resulting in indentations from the rolling elements.
With reference to fatigue failure of components, which of the following methods can be used on board a marine vessel to limit the possibility of fatigue failure to a propeller shaft?
A) Regular Lubrication, Dynamic Balancing, Shaft Alignment Ensure the propeller shaft is well-lubricated, dynamically balanced to minimize vibrations, and properly aligned with the engine and bearings.
Question: With reference to the hull of a vessel, describe how fatigue stress occurs whilst in a seaway.
B. The hull experiences repeated cycles of loading and unloading due to wave action.
Which of the following describes two destructive tests that a sample of metal intended for the manufacture of a propeller shaft would undergo before being accepted by a classification society?
A) Tensile Test and Impact Test
What is the term "safety coefficient" (factor of safety), and why is it required?
A) A numerical value used to account for uncertainties in material properties and loading conditions, ensuring that structures can support loads beyond the maximum expected loads.
With reference to a ball race bearing, what does the term "false brinelling" refer to?
A) Surface wear on the raceway caused by vibration and relative motion between stationary rolling elements and raceways when the bearing is not rotating.
What is a typical safety coefficient designed into a propeller shaft of a superyacht?
B) 2.0
Question: With reference to the hull of a vessel, describe how fatigue stress occurs whilst in a seaway.
B. The hull experiences repeated cycles of loading and unloading due to wave action.
With reference to the installation of copper pipes in engine cooling systems, which of the following are four recommendations for their installation?
A) Ensure Proper Support and Alignment, Use Correct Fittings, Avoid Sharp Bends, Apply Appropriate Insulation
Which of the following lists four methods for non-destructive crack detection?
A) Ultrasonic Testing, Magnetic Particle Testing, Dye Penetrant Testing, X-ray Inspection
With reference to the installation of copper pipes in engine cooling systems, which of the following are three possible causes for their premature failure?
A) Corrosion, Overheating, Vibration Fatigue
With reference to fatigue failure of components, how is material fatigue testing typically carried out in a laboratory?
C) Cyclic Loading Testing: The material is subjected to repeated cycles of loading and unloading, and the number of cycles to failure is recorded.
Question: With reference to the hull of a vessel: state the effect of fatigue on the hull material
B. Gradual weakening and cracking of the material.
With reference to fatigue failure of components, which of the following correctly describes the three stages of fatigue failure.
A) Crack Initiation, Crack Growth, Rapid Fracture Stage 1: Microcracks form at stress concentrators (e.g., surface defects or grain boundaries). Stage 2: The crack slowly propagates through the material under cyclic loading. Stage 3: The crack grows rapidly, leading to sudden failure of the component.
How can false brinelling be reduced in practice?
A) By using vibration dampeners or isolators to minimize vibrations during storage or transportation.
How is a Brinell hardness test carried out?
A) A hardened steel or carbide ball is pressed into the material's surface under a specific load, and the diameter of the indentation is measured to calculate hardness.
With reference to fatigue failure of components, how does the surface appearance of a fatigue fracture typically present?
D) Beach marks and striations: The fracture surface shows concentric rings (beach marks) and fine lines (striations) radiating from the crack initiation site.
