Wind-Tunnel Study of the ARMA Flutter Prediction Method
Work towards MSc degree under the supervision of Assoc. Prof. Daniella Raveh
Department of Aerospace Engineering
Technion – Israel Institute of Technology
Aeroelastic ﬂutter is a destructive instability phenomenon for which dedicated ﬂight test campaigns are considered compulsory according to airworthiness regulations. In these tests, the dynamic characteristics of the aeroelastic system are interpreted from measurements of the aircraft’s structural responses to external excitations. Over the years, several ﬂutter identiﬁcation and prediction techniques have been suggested to increase the eﬃciency of ﬂutter ﬂight tests and to enable better prediction of the ﬂutter boundary. While most of the methods rely on external mechanical excitation accessories, the Autoregressive Moving-Average (ARMA) ﬂutter prediction method attempts to identify the aeroelastic system based on the aircraft structural response to random air turbulence excitation.
This study investigates the application aspects and the methodology of flutter prediction via ARMA system identiﬁcation in a dedicated wind-tunnel experiment. For that purpose, an elastic wing was designed and manufactured using rapid prototyping. The wing was tested at the Technion’s subsonic wind-tunnel at subcritical points and all the way to ﬂutter.
The current study presents the ﬂutter prediction methodology and process as conducted numerically and in two wind tunnel experiments. The structural responses used for ARMA system identiﬁcation are acceleration and strains (measured by strain gauges) in the ﬁrst wind-tunnel test, and strains measured via optical ﬁbers in the second test. The study presents comparison of the ﬂutter prediction capability when based on discrete, spars measurement (accelerometers, strain gauges) versus that from more dense measurement (optical ﬁbers). The study focuses on the practical aspects of the application of the method in wind-tunnel testing, which is also of great importance for ﬂight testing.
The talk will be given in Hebrew
Wed, 10-10-2018, 16:30 (Gathering at 16:00)Classroom 165, ground floor, Library, Aerospace Eng.
Light refreshments will be served before the lecture