ASA 127th Meeting M.I.T. 1994 June 6-10

5aNS2. Experimental system identification of the interior acoustic field of a business aircraft.

G. P. Gibbs

C. R. Fuller

B. W. Mahnken

H. H. Ralston

Vibration and Acoust. Labs., Dept. of Mech. Eng., VPI & SU, Blacksburg, VA 24061-0238

This paper presents the results of a series of tests measuring the acoustic response of a Cessna Citation 3 fuselage. For all tests the acoustic response was measured using 90 Metravib microphones mounted in an array spanning the cross section of the aircraft. The array was scanned axially using a computer controlled system along the aircraft interior providing the response at 2790 locations. In the first test, excitation was provided by a point force shaker oriented radially and located at the left side engine pylon. The input force was measured using a PCB force transducer. During the second test, an acoustic driver mounted in the nose of the aircraft was used as the excitation. The paper will discuss the results of the system identification, including a comparison of the results of a modal analysis technique with those obtained using a two-dimensional Fourier transform technique.