In UTS calculation, which area is used in the denominator?

In UTS calculation, which area is used in the denominator?

• A. Current reduced area after necking
• B. Average cross-sectional area during loading
• C. Original cross-sectional area
• D. Final cross-sectional area at fracture

Answer: (C)

Ultimate tensile strength is defined as the maximum engineering stress in a tensile test, which uses the original cross-sectional area in the denominator. This keeps the value a consistent material property, even as the specimen plastically deforms and necks so its actual area changes. Using the current, necked area would give true stress, which changes with deformation, not a fixed material property. The area at fracture or an average area during loading would also tie the strength to a specific deformation state, not to the inherent strength of the material. So the denominator is the original cross-sectional area.

Ultimate tensile strength is defined as the maximum engineering stress in a tensile test, which uses the original cross-sectional area in the denominator. This keeps the value a consistent material property, even as the specimen plastically deforms and necks so its actual area changes. Using the current, necked area would give true stress, which changes with deformation, not a fixed material property. The area at fracture or an average area during loading would also tie the strength to a specific deformation state, not to the inherent strength of the material. So the denominator is the original cross-sectional area.