If the plate is modeled with solid elements, then you can define a pressure load (PLOAD4) to get the desired behavior. Pressures are follower loads (normal to the element face) when they aren't given a direction.
If the plate is modeled as shell elements, then you have no option but to use a FORCE entry in NASTRAN. NASTRAN doesn't support edge based pressures. NX 9 added follower force support by supporting the NASTRAN FORCE1 and FORCE2 entries.
1. Select the Force command
2. Set the Type to Magnitude and Direction
3. Set the Direction Method to Along 2 Nodes or Normal to 4 Nodes
Those methods in step 3 create FORCE1 and FORCE2 entries. In NASTRAN, as the nodes move, the force directions update.
Simulation Product Management
Product Engineering Software
Siemens Industry Sector
Siemens Product Lifecycle Management Software Inc.