5003 Lectures - Faculty of Engineering and Applied Science

E5003 - Ship Structures I 202
© C.G. Daley
Thin Walled Torsion
Torsion in thin walled sections differs greatly
between ‘open’ and ‘closed’ sections.
To examine the difference between open and
closed sections we first make some simplifying
assumptions;
• sections are prismatic
• no in-plane deformation (cross sections only
rotate)
• small out of plane deformations (warping)
Thin Walled Torsion – Open Sections
Consider an open section, built-in at its base and
subject to a torsion at the free end.
The section rotates about a point called the shear
center. Point ‘p’ moves in the y and z direction due
to rotation and in the x direction due to ‘warpage’.
The displacements of point ‘p’