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Torsional Stress

Q) Write short notes on Torsional Stress on ships.

Ans:- Torsional Stress on ships:

  • When a body is subject to a twisting moment which is commonly referred to as torque, that body is said to be in ‘torsion’. A ship heading obliquely (45°) to a wave will be subjected to righting moments of opposite direction at its ends twisting the hull and putting it in ‘torsion’.
  • In most ships, these torsional moments and stresses are negligible but in ships with extremely wide and long deck openings they are significant. A particular example is the larger container ship where at the topsides a heavy torsion box girder structure including the upper deck is provided to accommodate the torsional stresses.
  • Torsional stresses also occur due to unsymmetrical loading along the centre line of the vessel. (For example, too much load on the fwd-port side and at the aft-stbd side)