Square plate under pure shear

[jetmaker]

Question: In Patran, using NASTRAN as the solver, how do you load a square plate such that it is subjected to pure shear? I have a plate with a central hole, and am trying to demonstrate that the kt under pure shear is 4.

Any help is appreciated.

jetmaker

 

[SWComposites]

I would apply uniform loads to all 4 edges in a direaction parallel to the edge (in the appropriate shear loading directions), and fix one corner node in x and y freedoms (assuming the plate is in the x-y plane) and fix an adjacent corner in x or y (depending on which corner is selected) to fix free body rotations. Try this first with a plate without a hole to verify that a uniform stress stress is applied.

 

[sdm919]

Also, it helps if the node spacing on each edge is uniform. That way, the total load can be evenly divided between all the nodes on that edge. And to be precise, the “end” nodes on each edge should get one-half the load of the “interior” nodes.

I think Kt = 4 for an infinite plate, so the hole should be “small” relative to the plate dimensions if you want to match that result. As the hole gets larger, the effect of the boundary increases and you’ll get a different result. The plate edges will not remain straight for that case, they will deform into an “S” like shape.

If you are planning to model a real problem eventually, you might consider applying enforced displacements around the perimeter rather than loads. This might be more appropriate if you’re looking at hole in a portion of a web which is bounded by stiffeners.

 

[jetmaker]

Thanks for the reply SW and sdm919.

Using SW's approach, I got an answer within 1% of theoretical, so I am happy.

Thanks again.

jetmaker