A TWO-STAGE PSEUDO-INVERSE APPROXIMATION METHOD FOR THE IDENTIFICATION OF VISCOELASTIC STRUCTURE

This study aims to develop a two-stage pseudo-inverse approximation method for the identification of material properties of viscoelastic structures, which is described by the Boltzmann model and is probed by a cantilever probe. First, a first stage pseudo-inverse method was used to determine the equivalent M, C, and K matrices of a probe from the measured input and output data of a vibration test for the probe only. The equivalent material properties (c, k) of a viscoelastic structure were estimated by a second stage pseudo-inverse method using a reduced equation of motion for the combined system of probe and test viscoelastic structure. Since the signal processing of noises which connect to the measured data is the key point to influence the final identification results, a digital filter applied to the measured signals under different levels of noise interference is thus discussed in this paper. The numerical simulations and experimental results demonstrate that the identification method based on the two-stage pseudo-inverse approximation is feasible.