Exciter impedance and cross-axis sensor sensitivity issues in FRF estimation

Abstract

This paper studies the effect of shaker impedance and the way this parameter can affect the frequency response measurement (FRF) on structures. Three different shaker designs were used for this study to better understand the effect of the shaker impedance on the force transmissibility characteristic function. Analytical MKC models are used to derive equations and then the experiments were conducted to validate the model. Another effect that is studied here briefly is the cross-sensitivity of the sensors when subjected to lateral forces (or displacements) and bending. It is shown that this effect will lead to non-repeatable measurements, especially in the case of impedance heads. © The Society for Experimental Mechanics, Inc. 2012.