Vibration and Flutter Flight Testing

A clustering algorithm for reduced order modeling of shock waves

Imagine yourself looking out the window on a commercial flight at the aircraft engine outside. For four years, I worked at Honeywell Aerospace as product design engineer in a research team investigating flutter and forced response issues in turbomachinery for aircraft engines. Flutter is an aeroelastic issue that can cause near-instantaneous and catastrophic part failure. It results from the un...

A Historical Overview of Flight Flutter Testing

NASA Technical Memorandum 4720 A Historical Overview of Flight Flutter Testing

SUMMARY This paper reviews the test techniques developed over the last several decades for flight flutter testing of aircraft. Structural excitation systems, instrumentation systems, digital data preprocessing, and parameter identification algorithms (for frequency and damping estimates from the response data) are described. Practical experiences and example test programs illustrate the combine...

In-flight modal analysis – a comparison between sweep and turbulence excitation

At the end of the development cycle, a new aircraft is certified by means of in-flight flutter tests. These tests consist of flying the aircraft at different airspeeds and measuring the accelerations at a limited number of locations on the aircraft structure. The scope is to open the flight domain by verifying that the aircraft does not suffer from aero-elastic instabilities such as flutter. In...

Modeling and Detection of Limit-Cycle Oscillations Using Adaptable Linear Models

A method for modeling the flutter response of a thin winged aircraft is presented. A hybrid physical-adaptive modeling framework is proposed to separate the autoregressive and moving average flutter components. Adaptive oscillators set at the structural free-vibration modal frequencies of the wing represent the structure (the autoregressive component). The moving average filters represent signa...