Root Mean squared Deviation (RMSD)

In EMI technique, change in the admittance signatures reflects the
damage in the structure. The horizontal or vertical shift in the
signature or the appearance of new peaks or reduction of old peaks are
the key indicators of the damage. To calculate the deviation in the
admittance signature, RMSD is used which is common in SHM. Giurgiutiu
and Rogers in 1999 defined the RMSD index as where 鹿Gj is the
conductance after the damage at a jth frequency and 鈦癎j is the
conductance at pristine state at the same jth frequency respectively.

CC INDEX

CC index was used for the repeatability of the admittance signatures
in this thesis which is given as where xi is the conductance of the
signature-I and 饾懄饾憱 is the conductance reading of the signature- II at
the same frequency respectively. 饾湈饾懃 and 饾懃虆 are the standard deviation
and mean of signature- I respectively and 饾湈y and 饾懄虆 are the standard
deviation and mean of signature-II.