The GATE Grind

GATE 2026 AE – Question 16

Structures · Strength of materials: Strain energy, Castigliano's principles, three-dimensional Hooke's law, plane stress and strain, Euler buckling · 1 mark · Multiple choice

The number of independent elastic constants that a fully anisotropic linear elastic material can have is ______.

  1. 36
  2. 21
  3. 10
  4. 2

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Correct answer: (B) 21

Explanation

The 6 x 6 stiffness matrix relating stress and strain is symmetric because of the strain energy function, so it has $\frac{6 \times 7}{2} = 21$ independent entries.