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GATE 2023 MT – Question 26

Mechanical Behaviour of Materials · Fracture mechanics · 1 mark · Multiple select

When cracks propagate in a brittle material, the following option(s) is/are correct

  1. elastic strain energy decreases
  2. surface energy increases
  3. surface energy decreases
  4. elastic strain energy increases

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Show answer and explanation

Correct answer: (A) elastic strain energy decreases; (B) surface energy increases

Explanation

A growing crack relaxes elastic deformation around it, releasing stored strain energy. It simultaneously creates new free surfaces, which cost positive surface energy.

Therefore elastic strain energy decreases and surface energy increases: **A,B**.