Abstract
Air sound transmission loss (TL) of a finite elastic plate, placed in an infinite rigid baffle, is computed with regard to, first, a lack of near-grazing waves in incident sound field and, second, diffractive three-dimensional expansion of the sound field radiated by forced bending waves of the finite plate. It is shown that both effects lead to the lack of near-grazing sound waves in transmitted sound field what in turn appreciably increases TL compared with diffuse field and infinite plate. Below coincidence, especially at low frequences, the second effect usually predominates over the first. At coincidence, in contrast, the first effect always prevails and results in an increase of both TL and limiting frequency. Above coincidence, both effects are always negligible. The computations are compared with numerous measurements of various authors for glass panels of different dimensions and satisfactorily explain the well-known excess of experimental TL values over infinite-plate theory at and below coincidence. Nevertheless the familiar integration formula for infinite plate may be successfully used for finite panels with the only difference that the limiting integration angle of incidence becomes depending on acoustic wave number.
Published Version
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call