Acoustic Manipulation with Elastomeric Parabolic Reflectors and Applied Vacuum
Başlık:
Acoustic Manipulation with Elastomeric Parabolic Reflectors and Applied Vacuum
Yazar:
Apte, Saurabh Sanjay, author.
ISBN:
9780438107762
Yazar Ek Girişi:
Fiziksel Tanımlama:
1 electronic resource (110 pages)
Genel Not:
Source: Dissertation Abstracts International, Volume: 79-11(E), Section: B.
Özet:
This thesis describes a parabolic acoustic reflector with an inflatable reflecting surface, which has tunable gain and directivity. Conventional parabolic reflectors focus and amplify sound waves using metallic or plastic dishes with fixed geometries. This work presents a morphable reflecting surface that deforms into a concave structure to provide polar response and tunable gain considering the deformed geometry of the reflector. The deformable concave structure was a silicone elastomer (Ecoflex 00-10) with a coefficient of reflection approximately 0.9. This reflective coefficient suggests these silicone-based elastomers serve as reflective substrates for advanced morphable devices to manipulate sound. We experimentally determined the Youngs Modulus and the radial displacement achieved during pre-stressing the membrane over the aluminum reflector. For our parabolic reflector, acoustic gain and directionality depended on the level of vacuum applied to the elastomeric membranes, which affected the curvature of the paraboloid. Experiments performed in closed and open environments, along with simulations, demonstrate that the soft reflective surface was capable of transformation into a set of desired parabolic shapes between an initial planar geometry (neutral position) and configurations with varying curvature. The magnitude of the acoustic power gain obtained for vacuums below -1.7 kPa at frequencies greater than 7 kHz was comparable with gains of commercially available reflectors, and the directional response of the reflector was super hyper cardioid in nature. The maximum gain was also ~17 dB at 8.5 kHz. Simulations coupling mechanical deformation with acoustic shells agreed qualitatively with experimental results. These systems might find future uses for adjustable parabolic microphones, long-range communication devices, and tracking of sound sources.
Notlar:
School code: 0190
Konu Başlığı:
Mevcut:*
Yer Numarası | Demirbaş Numarası | Shelf Location | Lokasyon / Statüsü / İade Tarihi |
---|---|---|---|
XX(696469.1) | 696469-1001 | Proquest E-Tez Koleksiyonu | Arıyor... |
On Order
Liste seç
Bunu varsayılan liste yap.
Öğeler başarıyla eklendi
Öğeler eklenirken hata oldu. Lütfen tekrar deneyiniz.
:
Select An Item
Data usage warning: You will receive one text message for each title you selected.
Standard text messaging rates apply.