How should elliptical manhole covers be oriented on a pressure vessel shell___________________?
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Answer: B. circumferentially
Explanation
Cylindrical pressure vessels experience hoop stress that is twice as large as longitudinal stress. Elliptical manhole covers must be oriented so their major axis aligns with hoop stress. This circumferential orientation provides maximum structural strength around the vessel opening. Internal pressure creates tensile stresses acting in both longitudinal and circumferential directions. Manhole openings weaken pressure vessel shells, requiring reinforcement and careful positioning. Geometric alignment ensures the cover plate bridges the maximum stress direction effectively.
Boilers and industrial pressure vessels require access manholes for internal inspection and cleaning. Incorrectly oriented covers could lead to leakage or structural failure under high pressure. Safety standards mandate precise geometric placement of all access openings in pressure vessels. Longitudinal orientation would align the minor axis with maximum hoop stress, reducing safety. Dished ends have different stress distributions compared to the cylindrical shell body. Vertical or arbitrary placement ignores the directional nature of internal pressure stresses.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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