OMA analysis of a launcher under operational conditions with time-varying properties

• Published in: CEAS space journal Vol. 10; no. 3; pp. 381 - 406
• Main Authors: Eugeni, M., Coppotelli, G., Mastroddi, F., Gaudenzi, P., Muller, S., Troclet, B.
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01-09-2018; Springer Nature B.V
• Subjects: Aerospace Technology and Astronautics; Damping ratio; Engineering; Flight tests; Hilbert transformation; Modal analysis; Original Paper; Resonant frequencies; Dynamical identification; Launch systems; Launchers; Time-varying systems; Operational modal analysis; Output only
• ISSN: 1868-2502; 1868-2510
• DOI: 10.1007/s12567-018-0209-5

The objective of this paper is the investigation of the capability of operational modal analysis approaches to deal with time-varying system in the low-frequency domain. Specifically, the problem of the identification of the dynamic properties of a launch vehicle, working under actual operative conditions, is studied. Two OMA methods are considered: the frequency-domain decomposition and the Hilbert transform method. It is demonstrated that both OMA approaches allow the time-tracking of modal parameters, namely, natural frequencies, damping ratios, and mode shapes, from the response accelerations only recorded during actual flight tests of a launcher characterized by a large mass variation due to fuel burning typical of the first phase of the flight.