Your syntax for applying the deformation is correct. Perhaps your values of Displacement are not what you expect? We don't have your data to test, but since you are are displacing all nodes, I wonder if the end result is just a linear translation of your structure. In other words, the result of the deformation is just moving the structure uniformly in x,y and z.
Can you attach you structural model and Displacement variable? You can save them to a mat file and attach them to your post using the paperclip icon.
