A modal approach for dynamic response monitoring from experimental data

The objective of this paper is the definition and verification of an iterative procedure for the detailed monitoring of the dynamic response of a structural system based on the experimental modal model of the system on ground and a limited number of measurements in the operativing condition. The application of this approach only needs the modal characterization of the structure, achievable with a preliminary modal survey with an arbitrary large amount of experimental points, and it allows the monitoring of the structure during operativing conditions by reconstructing the overall response from the measurements of few sensors. The method is formulated starting from a linear model, but it can be applied to weakly non-linear system, because of the iterative nature of the algorithm. It does not require the definition of a numerical model but an experimental representation in the modal coordinates. The proposed method is presented as well as its implementation and several numerical test cases in order to validate its formulation. Experimental analyses are performed on an uniform beam and on an helicopter component with promising results. © 2013 by the American Institute of Aeronautics and Astronautics, Inc. All rights reserved.