Merjenje absorbcije zvoka in zvočne izolacije granuliranega materiala v ravnem zvočnem polju

Grohar, Andrej (avtor), Prezelj, Jurij (mentor)

Nedavne raziskave so razkrile, da lahko granuliran material, poleg zvočno-absorpcijskih lastnosti, izkazuje tudi nepričakovano visoko zvočno izolacijo, ki presega teoretične napovedi po masnem zakonu. Vzpodbudni preliminarni rezultati zahtevajo nadaljnje sistematične eksperimentalne raziskave. Rezultati teh raziskav bodo služili razvoju teoretičnega ozadja za nov fizikalni model zvočne izolacije granuliranih materialov. V zaključni nalogi smo določili frekvenčno odvisnost koeficienta absorpcije in zvočne izolacije glede na velikost granul. V sklopu naloge smo s sejanjem pripravili različne vzorce granuliranega materiala, ki so bili postavljeni v 3D tiskani epruveti za meritve v ravnem zvočnem polju. Prva epruveta ima na eni strani visoko porozen zaključek, medtem ko je druga zaprta s PVC folijo na obeh straneh. Poleg presejanega peska smo preučili akustične lastnosti tudi polistirenskemu in polimernemu granulatu. Meritve so bile opravljene z metodo impulznega odziva. Eksperimentalne rezultate se je ovrednotilo in analiziralo z osnovnimi statističnimi metodami. Zaključek naloge na podlagi rezultatov potrjuje hipotezo, da granulat s fino granulacijo izkazuje nepričakovano visoko zvočno izolacijo, ki ni odvisna od koeficienta absorpcije. S tem lahko akustičnemu elementu ki temelji na granuliranem materialu poljubno nastavljamo absorpcijo ali zvočno izolacijo, deloma pa tudi njuno kombinacijo.

• Jezik: Slovenski jezik
• Ključne besede: koeficient absorpcije, prenosne izgube, impedančna cev, metoda impulznega odziva, granuliran material, zvočna izolacija peska
• Vrsta gradiva: Zaključna naloga
• Tipologija: 2.11 - Diplomsko delo
• Organizacija: FS - Fakulteta za strojništvo
• Kraj izida: Ljubljana
• Založnik: [A. Grohar]
• Leto izida: 2023
• Št. strani: XIII, 27 str.
• PID: 20.500.12556/RUL-151870
• UDK: 534.231:62-492:691(043.2)
• COBISS.SI-ID: 182638595
• Datum objave v RUL: 24.10.2023

Sekundarni jezik

• Jezik: Angleški jezik
• Naslov: Measurement of Sound Absorption and Transmission Loss of Granular Materials in a Planar Sound Field

Izvleček

Recent research has revealed that granular material, in addition to its sound absorption properties, also exhibits unexpectedly high sound insulation that surpasses theoretical predictions based on the mass law. Promising preliminary results call for further systematic experimental investigations. The findings of these studies will contribute to the development of the theoretical framework for a new physical model of sound insulation in granular materials. In the final project, we determined the frequency dependence of the absorption coefficient and sound insulation with respect to granule size. Within the scope of the project, we prepared various samples of granular material through sieving, which were placed in 3D printed test tubes for measurements in a flat sound field. The first test tube had a highly porous termination on one side, while the second one was sealed with PVC film on both sides. In addition to sieved sand, we also examined the acoustic properties of polystyrene and polymer granules. Measurements were conducted using the impulse response method. Experimental results were evaluated and analyzed using basic statistical methods. The project's conclusion, based on the results, confirms the hypothesis that fine-grained granular material exhibits unexpectedly high sound insulation, which is independent of the absorption coefficient. This allows for the arbitrary adjustment of absorption or sound insulation, and partially their combination, in acoustic elements based on granular material.

• Ključne besede: coefficient of absorption, transmission looses, impedance tube, impulse response method, granular material, sound insulation of sand