Comparison of coefficient identification with experiment of squeeze film dynamics

The linear least squares method and the nonlinear spectral analysis technique were used to identify the coefficients from experimental data with a theoretical nonlinear model of dynamics with a viscous squeeze film. A series of sinusoidal and random experiments were carried out with different frequencies, amplitudes and gaps. The least squares procedure performs an optimum fitting mathematically, but the fitted parameters do not keep the original physically characteristics of a practical system. The spectral analysis technique represents the identification with the physically realizable parameters. A comparison and discussion are made.