20.500.12556/RUL-172727 Analiza zračne upornosti granuliranih materialov in določitev absorpcijskih lastnosti Analysis of airflow resistance in granular materials and determination of their acoustic absorption properties Magistrsko delo obravnava določanje zračne upornosti poroznih in granuliranih materialov ter analizo njihovih akustičnih absorpcijskih lastnosti. V ta namen je bila razvita in izdelana merilna naprava, ki omogoča meritve po standardih ISO 9053-1:2020 (enosmerni pretok) in ISO 9053-2:2020 (izmenični pretok). S pomočjo eksperimentalnih meritev na različnih materialih (pohištvena pena, melaminska pena, kosmit, pesek) in primerjave z referenčnimi podatki iz impedančne cevi so bile analizirane veljavnosti empiričnih modelov Delany–Bazley in Delany–Bazley–Miki. Rezultati kažejo, da modeli dobro opisujejo absorpcijske lastnosti klasičnih poroznih materialov, medtem ko pri granuliranih materialih (npr. pesek) prihaja do večjih odstopanj. Naloga prav tako izpostavlja omejitve merilnih metod in pomen natančne določitve specifične upornosti kot ključnega vhodnega podatka za akustične modele. This master’s thesis focuses on the determination of airflow resistance in porous and granular materials and the analysis of their sound absorption characteristics. For this purpose, a custom measurement device was developed and constructed, capable of performing tests according to ISO 9053-1:2020 (steady airflow method) and ISO 9053-2:2020 (oscillating airflow method). Experimental measurements were carried out on different materials (furniture foam, melamine foam, flocked fabric, and sandbox sand), and results were compared with reference data obtained from an impedance tube. The validity of empirical acoustic models, specifically Delany–Bazley and the improved Delany–Bazley–Miki model, was evaluated. The results show that these models accurately predict absorption in classical porous materials, while larger deviations occur when applied to granular media such as sand. The thesis also highlights the limitations of the measurement methods and emphasizes the importance of accurately determining specific airflow resistance as a key input parameter for acoustic modeling. zračna upornost porozni materiali koeficient absorpcije zvoka akustični modeli Delany–Bazley Delany–Bazley–Miki impedančna cev granulirani materiali merilne naprave airflow resistance porous materials sound absorption coefficient acoustic models Delany–Bazley Delany–Bazley–Miki impedance tube granular materials measurement devices true false false Slovenski jezik Angleški jezik Magistrsko delo/naloga 2025-09-11 08:32:22 2025-09-11 08:32:24 2025-10-21 03:43:59 0000-00-00 00:00:00 2025 0 0 XX, 84 str. 2025 0000-00-00 NiDoloceno NiDoloceno NiDoloceno 0000-00-00 0000-00-00 0000-00-00 620.179.17:62-492-026.772(043.2) 276006 249846019 44179.pdf 44179.pdf 1 2E90B5884A1C22622B371E36CACBBF7E 8d9c94b43a1d13e7179f134e2ca57c02db1acabb4b913c508d02db588d9d6bac eab38ef0-8ed8-11f0-9328-0050569b8976 https://repozitorij.uni-lj.si/Dokument.php?lang=slv&id=216757 Fakulteta za strojništvo 0 0 0