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Description
Open-cell polyurethane (PU) foams are widely utilised for acoustic insulation in the automotive and industrial sectors; however, the foaming process often introduces significant spatial non-homogeneity and anisotropy. This variability complicates the prediction of macroscopic performance via standard semi-phenomenological models, such as the Johnson-Champoux-Allard (JCA) framework. This study presents a systematic experimental investigation into the spatial variability of PU foams within a single production batch, focusing on samples extracted from varying depths of the same injected block. The acoustic properties, specifically normal and random incidence sound absorption, were measured alongside an experimental characterisation of the five non-acoustic transport parameters. To bridge the gap between microscopic morphology and macroscopic behaviour, a semi-empirical multiscale approach was employed to evaluate transport parameters from structural characteristics. The novelty of this work lies in the implementation of an inversion technique designed to determine the reticulation index directly, rather than relying on estimates from microscopic images. Results demonstrate a significant reduction in the reticulation index as extraction depth increases. Validation against experimental data confirms that this approach provides a robust tool for the industrial design and optimisation of acoustic treatments with inherent density and morphological gradients.