Influence of frequency-dependent properties on system identification: Simulation study on a human pelvis model

The experimental identification of systems in structural dynamics is commonly achieved by adapting a parametric model so that its simulated response matches a set of measurements. Since in most applications the system mechanical properties are considered constant, standard identification tools assume the same. The question arises over the identifiability of systems which do not satisfy this assumption. The objective of this simulation study is to investigate the influence of frequency-dependent stiffness and damping properties on the system identification, as performed by two standard modal analysis tools and one in-house updating algorithm. Results indicated that the frequencies and the mode shapes are generally well estimated, while the damping ratios proved more difficult to be identified.