I have performed FEA on a 1" thick flat plate that is welded to the interior of a vessel. The plate has 2" dia holes on a 2-5/16" pitch.

I am now at the point of performing the stress linearizations. From Div 2, part 5, table 5.6 -"Perforated head or shell", the determination of the bending stress is described as, "Averaged through width of ligament, but gradient through the plate".

The stress classification plane (SCP) is along the length of a ligament. My software provides the linearized bending stress along the SCL's.

I understand the averaging portion, but have no clue regarding the "gradient" portion. Can somebody explain, and or, describe how to take into account the "gradient" part?

Regards,

I think "Gradient" means through the wall thickness of the plate.

Best Regards,

A. Zaki