In an FEM I'm working on (in NASTRAN), fasteners (beam elements) are creating very high regions of stress near the node they are connected to. In reality, I realize that the fasteners will have washers to help distribute the stress across the surface more effectively.
I've tried running some simulations with interpolation elements, but am not quite sure what DOF's I need to contraint for the independent and depenedant elements. The closest thing I've come to is using multiple springs (with a very high K) attached nearby the region the fastener inserts into.
Are there any better ways to approximate washers (i.e. realistic fastener loading) in NASTRAN?
Thanks in advance, Dave