Non-Parametric Operational Modal Analysis Methods in Frequency Domain: A Systematic Review

The objective of this research is to present a systematic review of the non-parametric modal analysis methods in the frequency domain. Peak picking (PP), frequency domain decomposition (FDD), enhanced frequency domain decomposition (EFDD), and frequency–spatial domain decomposition (FSDD) are revisited and didactically illustrated by means of modal identification for a study case proposed in previous researches. Algorithm schemes are illustrated to summarize these frequency domain OMA techniques. Modal frequencies, modal damping ratios, and modal shapes are estimated using the different OMA techniques and compared to estimations obtained by the free decay (FD) method reported in previous researches. These are employed to compare the results obtained by the methods presented herein and show a very good correlation in obtaining modal frequencies and a low correlation in the case of modal damping.