Analysis of ambient helicopter response data

摘要

There has been a significant amount of interest in the use of ambient response data (where the excitation is not measured) to determine the modal properties of a range of structures. In particular, much emphasis has been placed on the use of such methods for civil structures. There are a range of possible system identification methods that can be used, with perhaps the most popular being the stochastic subspace methods. In this paper, two methods (N4SID and ERA/DC) are used to analyse the in-flight responses from a helicopter as part of the GARTEUR AG-19 project. The ability of the methods to successfully extract frequencies, damping ratios and modeshapes is investigated. The ERA/DC method is enhanced through the use of the Kamursan and Tufts approach to automatically detect and eliminate spurious modes. This paper is proposed as part of the special session on the Garteur AG-19 project.