Bill Bulat
Ansys Employee

You could try defining remote displacements on the edges of the plate. For a simply supported case, constrain all 3 translational DOFs and leave the rotational DOFs free/undefined. For fixed support, constrain the 3 rotational DOFs as well. I think this should work whether the plate is modeled as a solid body (meshed with solid elements that only have translational DOFs) or a surface body (meshed with shell elements that also have rotational DOFs).