In pressure vessels with multiple openings, edge stress concentration is maximized locally and becomes negligible beyond an area spanning ______________ times hole diameter?
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Answer: A. Two
Explanation
Local stress concentrations around vessel openings diminish rapidly with distance from the cut edge. Engineering stress analysis proves that edge stress effects become negligible beyond a distance equal to two hole diameters. Reinforcing pads are sized based on this localized stress decay zone around nozzle cutouts in pressure vessels. Pressure vessels develop high localized mechanical stresses wherever shell plates are cut for nozzles or manways. Discontinuity stresses occur because structural loads must detour around the open penetration hole in the wall. Boiler and pressure vessel codes provide explicit rules for calculating required reinforcement areas around openings.
Extending stress concentration zones out to ten or twenty diameters overstates the localized nature of shell discontinuities. Assuming stress never decays would make pressure vessel nozzle design economically impossible due to massive reinforcement. Limiting the zone to a fraction of a diameter underestimates the actual structural redistribution of forces.
- Subject
- Engineering
- Category
- Chemical Engineering
- Topic
- —
- Difficulty
- medium
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