News: has a Community Board and Customer Support System. Submit a ticket at

Author Topic: proper direction of applied pressure load on ortho grid stiffened panel  (Read 1159 times)


  • Client
  • **
  • Posts: 4
When applying a pressure load on the surface of the panel, what is correct convention for pressure application? I want pressure applied on outer flat surface of ortho grid panel, so that deflection of panel is toward inward side where stiffening ortho grid web is assumed to be located. Looking at images in free body tab, positive pressure is in +Z direction, but is the ortho grid in the -Z side of plate?


  • Administrator
  • *****
  • Posts: 34
For pressure, HyperSizer uses the same sign convention as Nastran. That is, positive pressure acts in the same direction as the element normal vectors.

You are also correct that the stiffeners of a stiffened panel (including orthogrid) are considered to be on the -Z side of the surface. So to apply the pressure you desire (deflection inward), your pressure should act against the normal vectors, in the -Z direction.