5003 Lectures - Faculty of Engineering and Applied Science

E5003 - Ship Structures I 208
© C.G. Daley
Consider a channel section. A channel is a common
structural profile, but one that is asymmetric on
one axis. The center of area (centroid) and the
‘shear center’ are not at the same location.
What is the centroid? For one thing, it is a
property of the cross sectional area. But what does
it mean for the channel section? If we were to
want to use the section as a column and apply an
axial force that would only compress (and not
bend) the column, we would apply the force at the
centroid ‘g’. This is because a uniform stress in
the cross section would have a ‘center of force’ at
‘g’.
To find ‘g’ we use the standard formulations;