Kindly, I want to do a parametric analysis of SDOF under a harmonic forcing in order to get a force-displacement curve, would you please suggest me any software or reference about how to do that .
rowingengineer response seems to be computational/parametric design for automated topologies + geometries, but I suspect you mean solve a SDOF multiple times to see how a parameter varies (e.g. SDOF deflection under different loads).
If the first is what you want, use either Rhino+Grasshopper or Dynamo+Revit to get what you want. You would need to go through tutorials for both to do them - plenty on the net and youtube.
If the latter is what you mean, you can do any software (eg SAP2000) by solving it multiple times. If you need a lot of iterations (therefore require automation) I would suggest OpenSEES. It is an excellent black box specialising in dynamic analysis. No GUI unfortunately, but doing a SDOF is not very complicated even for someone new to the software. Tutorials exist with one SDOF, so maybe just change the numbers to your values, and you are good to go? See link: Link
PS.I believe there is a way to perform batch analysis in SAP2000, but don't remember the way, it's been years since I did it. Not much simpler than doing it in OpenSEES though.
Parametric analysis.... Like studying the effects of length changes vs mass changes and such?
I don't really think you need a program for that. For a single degree of freedom system, you should be able to calculate the effect of each parameter directly. I'd say that Excel might be where you want to start, allowing you to graph the effects of various parameters.
I suspect that OP is looking for the harmonic force is applied to a single DOF structure.
If this is the case, you may use SAP 2000 . For hand calculation or excell spread sheet,in order to get the concept, you may look ACI 351.3R-04 Foundations for Dynamic Equipment.
Just write driven harmonic oscillation and one of the outcome,