The influence of parameter choice in operational modal analysis: A case study

Abstract

Even if the development of several software packages has facilitated the performance of experimental and operational modal analysis in recent years, modal identification is still a complex task which requires experience and a solid theoretical background of the analyst since the results are influenced by several factors. One of these factors that may have a significant influence on the results is the choice of parameters that govern the respective algorithm. Even though it is generally well known by experienced analysts that the parameter choice has an influence on both the performance of an algorithm and the results, this topic has been hardly addressed in literature. The influence of some of these parameters on the identification of modal parameters by means of the covariance-driven SSI and the Poly-reference least-squares complex frequency domain method (p-LSCF) were investigated in a case study. For several modes, clear trends related to respective analysis parameters became obvious. Even though such clear findings could not be identified for all modes, respective influences and resulting uncertainties were observed and quantified.