Case study: Hybrid inverse method for aircraft noise abatement isolator: Experimental and vibroacoustic assessment

Abstract

In the aeronautical industry, the vibrations generated by mechanical systems produce unwanted noise perceived by users, which affects their comfort. Engineers encounter several difficulties in carrying out experimental measurements when studying complex systems. To solve this problem, a solution was proposed for the manufacturers' benefit, allowing them to access the various identified measurement points, describe the systems' vibroacoustic behavior, whether coupled or decoupled, and share the work between several teams and reduce the time spent on measurements. This paper deals with the experimental study performed on an aircraft noise abatement isolator. The component-based transfer path analysis hybrid inverse method is developed to allow the work on the subsystems separately between several teams and characterize them on an external test bench outside real functioning conditions. The studied system consists of a mass coupled by a noise abatement isolator fixed in an aluminum plate backed by a concrete cavity. Several parameters are studied such as the number of transfer paths to be considered to see the effect of neglecting certain transfer paths, the effects of coupling versus decoupling of the connected substructures and the number of indicator points chosen and used in the inversion method. The results are compared to the direct method.