Materials science – name for materials with identical elastic properties in all directions In mechanics of materials, what do we call a material that exhibits the same elastic properties (such as modulus and Poisson’s ratio) in every direction?
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AIsotropic
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BBrittle
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CHomogeneous
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DHard
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EOrthotropic
Answer
Correct Answer: Isotropic
Explanation
Introduction / Context:Describing material symmetry is essential for selecting correct constitutive models. Engineers must distinguish isotropy, orthotropy, and anisotropy because directional dependence affects stress–strain predictions and design.
Given Data / Assumptions:
- Elastic range behavior only.
- No microstructural texture that would cause directional properties.
- Small deformations (linear elasticity context).
Concept / Approach:An isotropic material has elastic properties that are identical in all directions. A homogeneous material has properties uniform from point to point (spatially), but they can still be direction-dependent. Brittle and hard are failure/strength descriptors, not symmetry classes. Orthotropic has three mutually orthogonal planes of material symmetry (direction-dependent).
Step-by-Step Solution:Map definition: same elastic response for any loading direction → isotropic.Reject others based on meaning (not symmetry or not direction-independent).
Verification / Alternative check:Common isotropic examples: fully annealed metals, glass, and many polymers (approximately). Wood and composites are orthotropic/anisotropic.
Why Other Options Are Wrong:
- Brittle/Hard: describe failure or hardness, not elastic isotropy.
- Homogeneous: uniform in space, not necessarily same in all directions.
- Orthotropic: direction-dependent along principal directions.
Common Pitfalls:Confusing homogeneity with isotropy; a material can be homogeneous yet anisotropic.
Final Answer:Isotropic