Prediction of the vibroacoustic response of a structure-liner-fluid system based on a patch transfer function approach and direct experimental subsystem characterisation

TL;DR

This paper introduces a novel experimental approach to predict the vibro-acoustic response of structure-liner-fluid systems using patch impedance coupling, avoiding reliance on material parameters and enabling accurate characterization of poroelastic liners.

Contribution

It develops a direct experimental method for determining impedance matrices of layered poroelastic materials, including boundary conditions and cross terms, improving prediction accuracy over existing numerical methods.

Findings

Experimental impedance matrices can be accurately measured for poroelastic liners.

The method effectively accounts for non-reciprocal cross terms and boundary conditions.

An air gap correction improves surface impedance measurement accuracy.

Abstract

The vibro-acoustic response of a structure-liner-fluid system is predicted by application of a patch impedance coupling methodology. In contrast to existing numerical approaches, impedance matrices of structure and liner are determined by a direct experimental approach, avoiding the requirement of material parameters. Emphasis is placed on poroelastic lining materials. The method accounts for surface input and transfer terms and for cross and cross-transfer terms through the specimen. A single test-rig characterisation procedure for layered poroelastic media is proposed. The specimen is considered as a single component -- no separation of layers is necessary. Problem specific boundary conditions for skeleton and fluid, which may cause non-reciprocal cross terms, are dealt with by the procedure. Methods of measurement for the assessment of impedance matrices are presented and their accuracy and limitations are discussed. An air gap correction method for surface impedance measurements is presented.