close thin wall beam vs open thin wall beam

[mdama]

Does anyone know the difference in shear stress between close thin wall circular beam vs open one is?

 

[KootK]

Some sketches of these cross sections and the loads applied to them would be helpful.

In the broadest of terms:

1) If you've got one slot in the section and it's on the centroidal axis conincident with the applied load, the peak shear stresses might be the same.

2) If you've got one slot in the section and it's on the centroidal axis perpendicular to the applied load, the peak shear stress might be double the value of that for the closed cross section.