Experimental Identification of Mechanical Structure with Characteristic Matrices : Proposition of Curve Fitting in the Frequency Domain and MCK Identification Using Curve Fitting

Abstract

It is not always possible to obtain characteristic matrices from modal parameters obtained by experimental modal analyses, such as curve fitting. If the degrees of freedom of the mathematical model are different from those of the structure identified, which occurs in almost all cases, contradiction occurs between the modal parameters when transformed to physical parameters. This paper proposes certain constraints that modal parameters must satisfy in order to be transformed to mass, stiffness and damping matrices without contradiction. A nonlinear optimization technique is used to solve these contraints. A new multireference curve fitting method in the frequency domain is also proposed. The number of unknown parameter depend only on the number of degrees of freedom identified, regardless of the number of response points. This method is effective when there are a number of response points. some experimental models are examined to validate this method.