Sound Radiation From Vibrating Plate With Different Boundary Conditions Using Discrete Source Technique

• Main Author: Ab. Latif, Nurain Shyafina
• Format: Thesis
• Language: English; English
• Published: UTeM 2016
• Subjects: T Technology (General); TA Engineering (General). Civil engineering (General)
• Online Access: http://eprints.utem.edu.my/id/eprint/18613/; https://plh.utem.edu.my/cgi-bin/koha/opac-detail.pl?biblionumber=100938; HF5351.M34 2016

The study of sound radiation from vibrating plate is an important subject in acoustic and being widely explored throughout years. The aims of this thesis are first to develop sound radiation model from a vibrating plate using discrete elementary source for different boundary conditions such as free-free, simply-supported and clamped-clamped. Secondly, the aim is to validate the radiation efficiency model between the proposed method and the experimental data. Analytical models of the sound radiation a rectangular plate are often based on simply supported edges for its mathematical convenience. Models for other boundary conditions also exist, but mostly these employ rather complicated analytical calculations. This study presents a mathematical model of the radiation efficiency for a baffled plate using a discrete elementary source model. The plate velocity from each element on the plate has been determined from Finite Element Analysis (FEA) then was inserted into MATLAB for radiation efficiency calculation. The model requires only the knowledge of the spatial distribution vibration velocity of the panel and hence, the surface velocity can be calculated conveniently by using the established mobility equations for different boundary conditions. The model from FEA has validated with theoretical model. After the validation, which the model from FEA shows good agreement with the theoretical model, then the radiation efficiency can be determined using velocity data from FEA modeling. For validation, the experiment was done in small chamber and reverberation chamber. The sound power was measured using reciprocal technique because of its convenient (time efficient, less cost) compared to direct method which needs the use of shaker. The experimental results are presented for free-free and clamped-clamped boundary conditions which show reasonable agreement with the predicted results. On the basis of the results of this research, it can be concluded that the clamped-clamped boundary condition has the highest radiation efficiency compared to free-free and simply-supported boundary conditions. The model to calculate the radiation efficiency from vibrating plate using discrete elementary source has been successfully modeled and validated with the experimental data.