Difficulty: Easy
Correct Answer: equal to
Explanation:
Introduction:
Ductile materials exhibit significant plastic deformation before fracture. A common design heuristic is that, unlike brittle materials, ductile metals show approximately similar resistance in tension and compression at ultimate strength levels, which informs failure theories and safety checks.
Given Data / Assumptions:
Concept / Approach:
For ductile metals, yielding is governed by shear-dominated criteria (e.g., distortion energy), and ultimate strengths in tension and compression are of similar magnitude. In practice, compressive strength can be slightly higher due to suppression of necking and different instability modes, but the widely taught simplification is that they are taken as approximately equal for basic comparisons.
Step-by-Step Solution:
1) Review tensile test results: UTS determined from maximum load/area.2) Review compression test: plastic flow without a brittle break; large strains.3) Compare: for ductile metals, ultimate strengths are close; design texts often treat them as equal in concept questions.4) Conclude: tensile strength ≈ compressive strength for ductile materials.
Verification / Alternative check:
Reference failure theories (e.g., von Mises) emphasize shear energy, supporting near-symmetry of strength in tension and compression for ductile metals.
Why Other Options Are Wrong:
Less than / greater than: oversimplify and can mislead; equality is the standard teaching assumption.
Cannot be generalized / depends only on geometry: material behavior, not just geometry, controls strength.
Common Pitfalls:
Confusing ductile with brittle behavior (e.g., concrete, cast iron), where compressive strength is far greater than tensile strength.
Final Answer:
equal to
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