How is rupture stress defined________________?
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Answer: D. load at breaking point/neck area
Explanation
Rupture stress calculation requires dividing the final applied load at the breaking point by the minimum necked cross-sectional area. As ductile tension specimens elongate, localized necking drastically reduces the cross-sectional area right before the final fracture occurs. Using the final reduced neck area yields an accurate representation of the true ultimate stress sustained by the material at fracture. Tensile testing generates engineering stress-strain curves alongside true stress-strain curves to evaluate metal mechanical properties. Necking is a localized instability phenomenon where plastic deformation concentrates in a specific region of a tensile test specimen. Engineering stress incorrectly uses the original un-deformed cross-sectional area, whereas rupture stress accounts for actual final geometry.
Breaking stress alone is an ambiguous term unless explicitly defined using the correct instantaneous minimum neck cross-sectional area. Dividing maximum load by original cross-sectional area calculates engineering ultimate tensile strength rather than true local rupture stress. Using breaking load divided by original area ignores the severe cross-sectional area reduction caused by localized necking deformation.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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