Exam Question
Explain Creep, Brinelling, Fretting, and Fretting corrosion. State with reasons, where these may occur in a ship propulsion system.
Class 2 (2nd Engineer)
MEKG
📅 Sep 2019
Reference Answer
(a) Explaining Creep, Brinelling, Fretting, and Fretting Corrosion:
Creep:
Creep is the time-dependent permanent deformation of a material under sustained stress at elevated temperatures. It occurs at stresses significantly below the material's yield strength. The rate of creep depends on material properties, temperature, time under load, and the applied stress. Creep progresses in three stages: primary (decreasing rate), secondary (constant rate), and tertiary (rapidly increasing rate leading to failure). An example is the creep of a turbine blade, causing it to contact the casing and fail.
Brinelling:
Creep:
Creep is the time-dependent permanent deformation of a material under sustained stress at elevated temperatures. It occurs at stresses significantly below the material's yield strength. The rate of creep depends on material properties, temperature, time under load, and the applied stress. Creep progresses in three stages: primary (decreasing rate), secondary (constant rate), and tertiary (rapidly increasing rate leading to failure). An example is the creep of a turbine blade, causing it to contact the casing and fail.
Brinelling:
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