Damage detection using ARMA model coefficients

The objective of this paper is to perform damage detection utilizing the coefficients obtained from an ARMA model. The Damage Index Method has been proven to be one of the better modal based damage detection methods currently in use. One major drawback to this method is the need to determine mode shapes from the frequency response function (FRF) data. Extracting mode shapes from FRF data can be extremely time consuming and the result at times can be highly dependent on the users knowledge and the application of the software package being utilized to extract the modal parameters. In an attempt to minimize user interaction in the damage detection process and to eliminate the need to determine modal parameters, we will develop a method which is capable of providing damage detection results from accelerometer time histories. This will be accomplished by utilizing the parameters of an ARMA model as damage indicators. Expressions for classification is attempted for a simply supported beam which contains damage of various degrees at several locations. The damage detection result will then be compared to the damage detection results obtained by the Damage Index Method.