Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
Results
Showing 1 to 20 of 47 for “"sound radiation"”.
-
Sound radiation from perforated plates
… means of engineering noise control to reduce the sound radiated by structures. However, there appears to be a lack of representative models to determine the sound radiation from a perforated plate. The aim of this thesis is to develop such a model that can be used to give quantitative guidance …
-
Sound radiation prediction by scale models
… of acoustic modelling has been concerned with sound quality inside rooms and auditoria. Little attempt has been made to model the structural stiffness of the walls. These "rigid" walled models have given good results for auditoria but cannot be used for vehicles etc. On the other hand the …
-
Aeroacoustic computation of sound radiation from ducts
… to accurately and efficiently predict noise radiation from ducts. The solver is based upon a hybrid methodology whereby only the acoustic near-field is solved using the developed numerical solver, with the resultant far-field directivity determined from an integral solution of the Ffowcs …
-
Plane Wave Sound Radiation From Mobile Dislocation Walls
Made available in DSpace on 2015-05-12T21:41:51Z (GMT). No. of bitstreams: 2 license.txt: 4848 bytes, checksum: 96035ab3f5e1c23cc7138a224ce498bd (MD5) 6915382.PDF: 3884868 bytes, checksum: 4baa7a010e5500aeecb6ad207c909954 (MD5) Previous issue date: 1969
-
Effect of sound radiation from plate attached with absober
… to contribute to substantial vibration and sound radiation, which lead to excessive noise. So, the study was carried out by determine the sound pressure radiated from simply support plate (SSP) without absorber and compared with attached single absorber in term of vibration reduction. Later, …
-
Sound Radiation Responses and Acoustic Behvior of Sandwich Panel
Sandwich structures with decent sound insulation and absorption properties have been widely used in the engineering fields such as aerospace engineering, marine engineering and civil and construction engineering. Investigations on the acoustic behavior of sandwich structures is of practical …
-
Decentralized control of sound radiation from periodically stiffened panels
… has previously been used to reduce low-frequency sound radiation from relatively simple laboratory structures. However, significant implementation issues have to be addressed before active control can be used on large, complex structures such as an aircraft fuselage. The purpose of this project is …
-
Active control of sound radiation from fluid loaded plates
Active control of sound radiation due to subsonic wave scattering from an infinite or a finite fluid-loaded plate excited below the critical frequency is analytically studied. The disturbance is caused by a flexural wave in an infinite plate, or by a point force on a finite plate at subsonic …
-
Control of Sound Radiation From Structures with Periodic Smart Skins
… skin concept for the reduction of the radiated sound power from a vibrating structure is proposed. The skin has a periodic structure and continuously covers a vibrating beam. Thus, this skin decouples the vibrating structure from the acoustic field by modifying the wavenumber spectrum of the …
-
Acoustically induced vibration of, and sound radiation from, slender beams
… structures and a surrounding fluid medium. The sound radiated from an unbaffled slender cylindrical beam vibrating transversely at resonance is calculated by solution of the classical wave equation subject to the boundary conditions imposed by the motion of the beam. The relationship between …
-
Vibrations of and sound radiation from some periodic structures under convected loadings
… shells excited by random convected loadings. The sound power radiated under these conditions is also dealt with. The stiffened structures are represented by uniform beams, plates or shells on periodically spaced elastic supports which represent stiffener-skin interaction forces and moments. The …
-
The optimal design of transducers for active control of multiple-frequency structural sound radiation
… of active structural acoustic control (ASAC) of radiation from elastically supported plates under multiple-frequency excitation. The control is achieved by use of piezoelectric (PZT) actuators. An optimization procedure is developed to find the optimal locations of actuators with which the …
-
A Distributed Active Vibration Absorber (DAVA) for Active-Passive Vibration and Sound Radiation Control
… vibrations and their associated radiated sound. It is a contribution to the research of efficient and low cost devices that implement the advantages of active and passive noise control techniques. A theoretical model has been developed to investigate the potential of this new …
-
Comparison of theoretical and experimental sound radiation patterns from a water loaded flexural disk transducer.
Measurements of the sound radiation patterns in water from the flexural vibrations of a clamped-edge steel disk have been made and are compared with the results of theoretical calculations made by Alper and Magrab (Journal of Acoustical Society of America, Vol. 48, Number 3, pp. 681-691, 197 0) for …
-
Active control of sound radiation due to subsonic wave scattering from discontinuities on thin elastic beams
… been made in recent years in active control of sound radiation from vibrating structures. Reduction of the far-field acoustic radiation can be obtained by directly modifying the response of the structure by applying structural inputs rather than by adding acoustic sources. Discontinuities, which …
-
Underwater sound radiation from single large raindrops at terminal velocity: the effects of a sloped water surface at impact
… bubbles that radiate significant underwater sound energy. Those studies identified two diameter ranges that produce bubbles: small drops (.8-1.1 mm diameter) which produce bubbles by one mechanism and large drops (2.2-4.6 mm diameter) which create bubbles by a different mechanism. Effects of …
-
Active control of sound transmission/radiation from elastic plates using multiple piezoelectric actuators
… a theoretical analysis of active control of sound radiation from elastic plates with the use of piezoelectric transducers as actuators. A strain-energy model (SEM), based upon the conservation of strain energy, for a laminate beam with attached or embedded finite-length spatially distributed …
-
Optimum design for feedforward structural-acoustic control of complex structural systems
… the relative contributions of the modes to the sound field providing a better understanding of how they have to be controlled in order to minimize sound radiation. Finally, the design approach is validated in an experimental arrangement for the attenuation of sound radiation from and enclosed …
-
Structure Borne Noise Analysis Using Helmholtz Equation Least Squares Based Forced Vibro Acoustic Components
… noise reduction strategy. Structure-borne sound is generated or transmitted through structural vibration; however, only a small portion of the vibration can effectively produce sound and radiate it to the far-field. Therefore, cost-effective noise reduction is reliant on identifying and …
Page 1 of 3