Mechanics of materials — material property terminology A material that has identical elastic properties (moduli) in all directions at a point is termed:

Introduction / Context:
Material symmetry assumptions greatly simplify stress–strain modeling. Knowing the correct terminology helps in selecting constitutive models for structural and geotechnical analysis.

Given Data / Assumptions:

• Linear elasticity context.
• Properties considered at a point (local material behavior).
• Terminology distinguishes directional dependence and spatial uniformity.

Concept / Approach:

• Isotropic: same elastic properties in all directions at a point (characterized by E and ν in 3D).
• Orthotropic: three mutually orthogonal planes of material symmetry with distinct properties in each direction.
• Homogeneous: properties uniform from point to point (spatially), not necessarily directionally uniform.
• Visco-elastic: time-dependent elastic response.

Step-by-Step Solution:
Match definition “same in all directions at a point” to isotropy.Differentiate from homogeneity (spatial uniformity) and orthotropy (directional dependence).Rule out viscoelastic behavior because it concerns time dependence, not directional symmetry.

Verification / Alternative check:
Isotropic Hooke’s law uses two constants (E, ν or G, K), confirming identical directional response.

Why Other Options Are Wrong:
Homogeneous says nothing about direction. Orthotropic explicitly varies by direction. Visco-elastic addresses rate/time effects. “Anisotropic” is the general opposite of isotropic.

Common Pitfalls:

• Conflating isotropy with homogeneity; many materials are homogeneous yet anisotropic (e.g., rolled metals).
• Ignoring that soils and composites are often anisotropic or orthotropic.

Final Answer:
Isotropic