Admittance boundary conditions and sound pressure field estimation of vibro-acoustic systems using an extended Kalman filter and parametric model order reduction

Abstract

Time-domain vibro-acoustic finite element simulations have been recently used in auralization and virtual sensing. However, when comparing the transient response based on a finite element model to actual measurements, often discrepancies are seen due to, amongst others, the presence of inaccurate admittance boundary conditions. To achieve accurate time-domain simulations, these uncertainties need to be included in the time-domain simulation. In this paper, the admittance boundary conditions are modelled using the superposition of several passive functions whose parameters are considered as the additional states in an extended Kalman filter scheme. Finite element models for vibro-acoustic systems including admittance boundary conditions have a high computational cost and result in frequency-dependent damping matrices. To get a smaller time-domain model, stability-preserving model order reduction is employed to reduce the number of degrees of freedom while maintaining a good accuracy and stability. Furthermore, to preserve the parameter dependency, parametric model order reduction based on a Taylor series expansion is employed. Experiments are performed on a vibro-acoustic system including a foam layer which can be represented by admittance boundary conditions. These conditions are identified and it is shown that the predicted sound field pressure is improved significantly as compared to the direct time-domain simulation.