Size optimization to specific value

Hi,

I'm trying to optimize the stiffness of a structure to a specific displacement value by changing material properties. This works fine so far but I did not figure out yet how I can set my objective that the displacement response has a specific value at the end.

Simple example:

I have a straight beam with an axial load. I want to run an optimization changing Young's modulus of the beam in order to get a nodal displacement of 2mm.

Best regards

Stefan