A Patch Transfer Function Approach for Combined Computational-Experimental Analysis of Vibro-Porous-Acoustic Problems

Abstract

Driven by both the ever-increasing tightening of legal regulations and the growing customers’ expectations, the noise, vibration and harshness (NVH) is becoming a crucial aspect in the vehicle development process. To achieve the NVH targets set for modern vehicles, sound insulation materials became an indispensable instrument to improve the vibro-acoustic behaviour. Typically, the sound insulation materials take advantage of so-called porous materials, which exhibit favourable properties when it comes to structural damping as well as transmission and absorption of sound. However, due to the highly complex material micro-structure and the sound propagation mechanisms involved the computational modelling of porous materials is a fairly challenging topic. An efficient yet accurate prediction of the NVH attributes of sound insulation materials therefore remains an unresolved issue. This chapter reports on recent developments based on so-called Patch Transfer Function (PTF) approach. Here the PTF approach is adopted for the analysis of coupled vibro-acoustic problems involving porous domains. The PTF is a sub-structuring technique that allows for coupling different sub-systems via impedance relations determined at their common interfaces. The coupling surfaces are discretised into elementary areas called patches. Since the impedance relations can be determined in either numerical or experimental manner, the PTF approach offers very high degree of versatility and is hence well-suited for combining test and simulation data into one workflow. Efficiency of the methodology proposed has been demonstrated by means of a validation example consisting of a rigid cavity backed by a dynamic plate with porous treatment. The full-system measurements are compared with the PTF predictions based on component measurements and/or simulations.