Analysis of Noise Reducing Materials Impact on UA Noise Emissions
Analýza vlivu tlumících materiálů na snížení hlukových emisí UA
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České vysoké učení technické v Praze
Czech Technical University in Prague
Czech Technical University in Prague
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Tato bakalářská práce se zabývá snižováním hluku bezpilotních letadel. Hluk je potřeba snižovat kvůli tomu, jak je nepříjemný a umí být škodlivý pro lidské zdraví. V této práci bude pro snížení hluku využito přidávání materiálu okolo krytu pohonné jednotky, a také pomocí tzv. vnitřních struktur. Konkrétně byly použity tři různé materiály a jeden druh vnitřní struktury se třemi jinými obsahy výplně. Pomocí tlumících materiálů se podařilo hluk snižovat, kdy nejlepší materiál byl polyurethanový panel, který snížil hluk v obou směrech měření (45° a 90°), a to nejlépe ve směru 90° od motoru, ve kterém se podařilo snížit hluk o 2,64 dB. Naopak u vnitřních struktur se hluk podařil snížit pouze v případě vnitřní struktury s 10 % výplní ve směru 90° od motoru. Ve všech ostatních případech se hluk od motoru zvyšoval. Ve výsledcích jsou taky porovnávány všechny varianty vůči sobě. Kromě vlivu na hluk byl také zkoumán vliv na ztrátu tahu motoru, který ovlivňovala hmotnost testované varianty.
This bachelor's thesis focuses on reducing the noise of unmanned aerial vehicles (UAVs). It is important to reduce noise because it is unpleasant and can be harmful to human health. In this work, noise reduction was approached by adding damping materials around the power units casing and by using internal structures. Specifically, three different materials and one type of internal structure with three different filling densities were tested.The use of damping materials proved effective in reducing noise. The best-performing material was a polyurethane panel, which reduced noise in both measured directions (45° and 90°), achieving the most significant reduction of 2.64 dB in the 90° direction from the motor. In contrast, the internal structures only managed to reduce noise in the case of the structure with 10 % filling density, and only in the 90° direction. In all other cases, the noise level increased.The results also include a comparison of all tested variants against each other. Besides the impact on noise, the influence of the added material's weight on the motors thrust loss was examined, as the additional mass directly affected the performance of the power unit.
This bachelor's thesis focuses on reducing the noise of unmanned aerial vehicles (UAVs). It is important to reduce noise because it is unpleasant and can be harmful to human health. In this work, noise reduction was approached by adding damping materials around the power units casing and by using internal structures. Specifically, three different materials and one type of internal structure with three different filling densities were tested.The use of damping materials proved effective in reducing noise. The best-performing material was a polyurethane panel, which reduced noise in both measured directions (45° and 90°), achieving the most significant reduction of 2.64 dB in the 90° direction from the motor. In contrast, the internal structures only managed to reduce noise in the case of the structure with 10 % filling density, and only in the 90° direction. In all other cases, the noise level increased.The results also include a comparison of all tested variants against each other. Besides the impact on noise, the influence of the added material's weight on the motors thrust loss was examined, as the additional mass directly affected the performance of the power unit.