Flutter excitation

The purpose of a flutter exciter is to impart a vibration into a structure. An excitation system, carried by the flight test aircraft, allows for energy input into the aircraft structure to excite all the natural modes. During flutter flight testing these structural vibrations are measured by accelerometers and the responses are used to determine if flutter onset is likely or not.

A flutter excitation system improves the signal to noise ratio of the accelerometer responses and provides higher fidelity structural data. The flutter exciters used by the CSIR are based on an Annular wing concept. This type of system is currently used on civilian and high speed military aircraft.

The annular wing excitation system provides excitation over a programmable frequency range and duration. The exciters comprise an annular wing to induce oscillating loads, an electric motor to drive the annular wing, two full-strain gauge bridges and electronics housed at the back of each motor to receive encoder signals used to drive the motors through a differential encoder line receiver, strain gauge amplifiers and a DC-DC converter to power the circuit. The exciter is sufficiently compact to fit into a store and thus not influence the flutter characteristics of the store configuration being cleared.

John Morgan
Telephone number: 012 841 2738
Email: JMorgan@csir.co.za

Kimal Hiralall
Telephone number: 012 841 3187
Email: KHiralall@csir.co.za