When equal increments of load are added to a mild steel wire until it breaks, how do the recorded elongations behave_________________?
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Answer: D. increase uniformly first and then increase rapidly
Explanation
Mild steel exhibits linear elastic behavior where elongation is directly proportional to the applied load increment. Once the yield point is surpassed, the material undergoes plastic deformation with large increases in elongation. Incremental loading clearly demonstrates this transition from a stiff elastic response to rapid ductile yielding. Mild steel is a ductile material commonly used in structural engineering and mechanical components. The stress-strain curve for mild steel includes a distinct elastic region followed by a yield plateau. Ultimate tensile strength occurs after the yielding phase before localized necking leads to fracture.
Understanding the tensile behavior of structural steels ensures buildings and bridges remain within safe operating limits. Engineers rely on yield point data to prevent permanent plastic deformation during everyday structural loading. Material testing laboratories perform standard tensile tests to verify the mechanical properties of raw metals. Option A is wrong because elongations are decidedly non-uniform once plastic deformation begins past yielding. Option B incorrectly implies that rapid elongation never occurs during the later stages of tensile testing. Option C is backwards because elongation increases steadily at first before accelerating rapidly near failure.
- Subject
- Engineering
- Category
- Mechanical Engineering
- Topic
- —
- Difficulty
- medium
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