Abstract Summary
In experimental structural dynamics, reliable estimation of Frequency Response Functions (FRF) is important to correctly characterize a mechanical system. In Experimental Modal Analy-sis (EMA), the FRFs are used as input to a modal parameter estimation algorithm to obtain the modal characteristics of the system. Errors due to noisy measurements are inevitably present in the FRFs and propagate to the modal parameters. A consistent FRF-estimator with low uncer-tainty is therefore needed. Different FRF estimators have been proposed with some consistency when certain noise-related assumptions are fulfilled (H1, H2, etc.). To choose the appropriate frequency response function estimator, some information about the noise in the experimental setup must be known prior to the experiments. In this work we show how to use measurements of ambient noise, made prior to the experiments, to characterize different noise components in the experimental setup. The noise components can be used in the FRF estimation resulting in more accurate estimates. Also, this approach is more general as it relies on fewer noise-related assumptions compared to the conventional estimators. Simulation of an experimental setup based on a simple finite element model is used to present and validate the approach.
