I am working on a simple rotor disc model. I am aware of how to use software plotting. But I need the fundamental theory behind the Campbell diagram and how to plot the engine order lines. Please share your inputs. Regards.
An EO line is just a line starting in (0,0) with an "m" inclination, where "m" is the equivalent engine order. For example, a shaft unbalance will cause a frequency response of EO=2, or a propeller with N blades will have an aerodynamic response of an EO=N.