Glass fibre reinforced epoxy rotors, made using the Tailored Fibre Placement (TFP) method have been subjected to stepwise, increasing loading over a multi-stage test procedure. The introduced stresses cause gradual damage and non-linear corresponding changes of the dynamic behaviour which can be measured by non-destructive testing. Therefore, Experimental modal analysis is applied to determine the dynamic behaviour of the rotors for each damage state and each structural condition. The behaviour is characterized by modal parameters, such as mode shapes and their corresponding eigenfrequencies. Due to the changes of the material properties of composite rotors, caused by damage increase, the occurrence of mode shapes has undergone complex changes. Those may be mode shifting, splitting and swapping, which affects the correlation of the investigated mode shapes. An approach is developed that correlates the damage-dependent modal properties and provides unambiguous damage evolution and dynamic response sequences. Next, multiple algorithms are implemented and evaluated that provide a robust approach to identify and correlate modal parameters. For this purpose the ZERNIKE polynomials and the Modal Assurance Criterion (MAC) in combination with the frequency response criterion and a data processing approach are applied in order to characterise the changing modal properties of gradually-damaged composite rotors.