kiwinige,
Victor suggestion is correct, however, using prescribe displacement "may" over constraint the model at the application location creatingunrealistic strains/stresses. The reality is that all displacement are due to applied forces, however there are times that we know the displacement but not the force to accomplish it. In this cases you can applied a unit load (1 lb, 1 newton, etc) to the model find out howmuch it displaces. Sincemechanica is a linear code you can then calculate from this information how much more force will needs to be applied in order to accomplish the displacement required.
For example: if I have a cantiliver beam and a unit load (1 pound) is applied at the end. After running the modelthe displacement at the end is calculated to be 0.25 inches. If I want the final displacement to be 1 inch I will need to multiply the load by four (4 pounds). That is my displacement need to be multiply by 4 to get 1 inch, therefore, the load must be multiply by the same factor. The same trick works for any other quatity ( stresses, strain, etc).
Unit load Require Load
------------------------- =-----------------
Calulated displacement Require displacement
Cheers
