Aeroacoustoelasticity in State-Space Format Using CHIEF Regularization

This paper deals with aeroacoustoelastic modeling for analysis of the acoustic field inside an aircraft cabin. The aim is the identification of a state-space format for aeroacoustoelasticity equations applicable, for instance, for synthesis of an active control law devoted to cabin noise abatement. Specifically, attention is focused on the development of the aeroelastic operator, starting from a boundary integral equation method for the exterior compressible-aerodynamics solution. As is well known, in such a type of application of the boundary integral equation method, singularities occur in the algebraic equations resulting from discretization of the integral operator. Here, the discretized aerodynamic operator is regularized by using the CHIEF technique, that consists of augmenting the algebraic problem with homogeneous conditions at points in the interior domain (the cabin space, in our problem). Then, in order to obtain the state-space format model of the aeroacoustoelastic operator, the resulting trascendental aerodynamic transfer functions between structural Lagrangean variables and generalized aerodynamic forces are approximated through rational polynomials, and the additional aerodynamic states induced by their poles are included in the set of state-space variables.