GATE 2020 ME (ME2) – Question 48
The uniaxial compression test graph is for a 1 m long solid metal bar. Response is linear from O to yield point P and nonlinear beyond P. The rod is pinned at both ends. Find minimum diameter that prevents buckling before yield (mm), to one decimal.
Practise this question in The GATE Grind →
Show answer and explanation
Correct answer: 55 to 58
Explanation
Elastic modulus from OP is E=100/0.002=50000 MPa. Set Euler stress $\pi^2EI/(AL^2)=\pi^2Ed^2/(16L^2)$ equal to100 MPa. Thus d=(4L/π)√(100/50000)=56.941 mm, giving **56.9 mm**. A smaller diameter would buckle first.