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GATE 2021 ME (ME1) – Question 29

Machine Design · Shafts and springs · 1 mark · Multiple choice

Shear stress distribution on the cross-section of the coil wire in a helical compression spring is shown in the figure. This shear stress distribution represents

Linear shear-stress distribution across a spring-wire cross-section, offset from the centre. See the attached source image.
  1. Direct shear only
  2. Torsional shear only
  3. Combined direct and torsional shear
  4. Combined direct and torsional shear with curvature concentration

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Show answer and explanation

Correct answer: (C) Combined direct and torsional shear

Explanation

Pure torsion would be a straight line through the centre with equal opposite endpoint stresses. Direct shear shifts that line by a uniform contribution.

The displayed line is shifted and crosses zero away from the centre, showing **direct plus torsional shear (C)**. Curvature concentration would make the variation nonlinear.