Sign Convention

[davidnoc]

Hi All:
I am trying to understand the moment sign convention in the attached picture.In XY plane moment about Z axis is creating compression in upper flange but in the XZ plane moment about Y axis is creating tension in the upper flange. Is it right or am I understanding the right hand rule correctlly?
Thanks

 

[johnhors]

Moment about Y causes bending in the XZ plane, the upper flange is in a plane parallel to the global XZ plane and is therefore undergoing bending as well, one edge of the upper flange is in tension whilst the other edge is in compression.