The anti-oscillator model parameters linked to the apparent mass frequency response function

A finite element model of a structure provides a fine knowledge of the response but such a model may lead to a loss of a global comprehension of the structural behaviour. That is why the anti-oscillator model (AO model), that may be derived from a finite element model, was developed. The mass and stiffness matrices are required but they often can not be retrieved easily in the commercial softwares. This paper shows how to overcome this problem and finally how to avoid a numerical model of a structure to derive the AO characteristics.In fact, it is shown that the AO characteristics and the apparent mass frequency response function (FRF) are closely tied. Indeed, the AO mass are the residue of the partial fraction decomposition of this FRF, while AO frequencies are the poles. Consequently, the AO characteristics can easily be derived from an experiment which allow the determination of the apparent mass FRF.