Prediction of Aeroelastic Stability Boundary using Recursive Identification
Hiroshi Torii, PhD
Department of Business, Meijo University, Japan
(Visiting the Department of Statistics, Colorado State University)
Monday, April 3, 2006
E205 Engineering Building
An elastic plate located in a flow, such as an airfoil, bridge or high-rise building, has different natural frequencies and damping ratios from the one without a flow. This is due to the interaction between the structural vibration and aerodynamic force, and is called 'aeroelasticity'. In an airplane development, much attention has to be paid to the areoelastic phenomena. Especially, since a self-excited oscillation, called 'flutter', gives a fatal damage to a wing, flight flutter tests are conducted at the final stage of the development, which is to certify that a flutter does not occur in a flight envelope. Of course, flutter must never occur during the tests. Therefore, the prediction of stability boundary or stability margin based on the data measured is very important.
In this talk, I will explain the prediction method of flutter boundary speed using time series data of wing vibration. In the method, I use a recursive algorithm with a forgetting factor to identify/update the ARMA coefficients under nonstationarity. The stability margin is evaluated by the 'flutter prediction parameter' which is calculated from the AR coefficients. I will show experimental results applied to wind tunnel flutter tests.