A Comparison of Identification Methods for Estimating Squeeze-Film Damper Coefficients

Abstract

The problem of identifying the dynamic coefficients relating to inertia, damping, and stiffness, in a single degree of freedom model of squeeze-film behavior, is discussed. It is demonstrated that two methods—referred to as “invariant imbedding” and “state variable filter”—are applicable, and that both yield a recursive scheme for sequentially estimating all three coefficients. The methods are compared through an analysis of simulated data, where the coefficient values are known a-priori. This is followed by a presentation of some typical results obtained from experimental tests, using both transient and forced response data. The comparisons indicate that the state variable filter method is much superior, with respect to both computational efficiency and accuracy.