Exam Question
Explain briefly how the different moving parts of a main engie are subjected to various stresses. Name the stresses and justify by stating how they originate. (16)
Class 4 (4th Engineer)
MEKM
📅 May 2024
Reference Answer
### Introduction to Stresses in Main Engine Components
Stress is defined as the internal restoring force per unit area of a material subjected to external forces. In a large two-stroke marine diesel engine, the moving parts are subjected to complex, cyclical loading from several sources. The primary forces generating these stresses are:
1. **Gas Pressure:** The high-pressure combustion gases acting on the piston crown.
2. **Inertia Forces:** Forces required to accelerate and decelerate the reciprocating masses (piston, crosshead, part of connecting rod).
Stress is defined as the internal restoring force per unit area of a material subjected to external forces. In a large two-stroke marine diesel engine, the moving parts are subjected to complex, cyclical loading from several sources. The primary forces generating these stresses are:
1. **Gas Pressure:** The high-pressure combustion gases acting on the piston crown.
2. **Inertia Forces:** Forces required to accelerate and decelerate the reciprocating masses (piston, crosshead, part of connecting rod).
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