Active control of composite fuselage type structures with enclosed acoustic cavity

Abstract

An active structural acoustic control system for a composite fuselage type structure is developed in this paper. The focus of the active control system is the global reduction of the sound field in an enclosed acoustic cavity using structureintegrated sensors and actuators. Active structural acoustic control systems are commonly designed based on the acoustic radiation modes which diagonalize a radiation operator. In the case of interior sound radiation, this radiation operator is derived in this paper from the coupled acoustic modes, which take into account the boundary conditions of the coupled velocity from the fuselage type structure. This results in frequency-independent radiation modes which do not rely on the validity of the modal interaction approach. The latter one violates the continuity condition of the velocity along the coupling surface. Parameter studies regarding active control implementations are conducted in order to evaluate how many radiation modes need to be considered for achieving a global sound attenuation.

Analysis of an Acoustic Monopole Source in a Closed Cavity via CUF Finite Elements

“…Although, the error is strongly affected by the frequency shifting of the pressure response and if the areas of the curves are compared, the total error is reduced to 0.052%, which is more accurate than the simple pressure value comparison for this kind of curves with a very similar trend. Moreover, in the frequency range of the FEM analyses for the aircraft noise problem (around 500 Hz or below [22,32]), the differences between the two software are much smaller. The average values below 500 Hz for the box cavity will be around 2.5E-04% (max.…”

Recent Developments of an Aircraft Fuselage along Theoretical, Experimental and Numerical Approach - A Review

“…The asymmetric structure was proved to be most beneficial, with only 1% weight gains and a lot more available area. C.Hesse [4] proposed and built a theoretical model that actively attenuates sounds within an enclosed right cylindrical composite fuselage using a series of actuators and sensors integrated into the structure. The main objective was to construct a general mathematical model which was applicable to a wide range of fuselage designs.…”