If you wish to use a force on a face then tailor that force to cause a specific displacement then you probably wish to make use of a Design Study with Optimization. You would first setup a static study with the fixtures and forces attached to the geometry you desire. You would then make a Design Study with the applied force as a variable and some dimensional value as a goal. I've attached an example of this in action.
Additionally, this video goes over how to do an Optimization setup (GoEngineer - Design Study Optimization)
ok thanks! i think this will help