Effects of size and edge damping on measurement results for sound reduction index of glass pane

摘要

The influence of size and thickness of glass pane but also installation of specimen andniche effects were investigated. With an area greater specimen will provide lower soundinsulation results for respective glass pane, but area ratio of up to 2:1 will not showdifferences in sound insulation greater than 3 dB in the single-number quantity. Thedamping provided by energy dissipation in a glass pane or by energy transfer tosurrounding structures appreciably affects the measured sound reduction index at andabove the coincidence frequency region. For a laminated glass, sound reduction index inthe vicinity of the coincidence frequency is influenced by the internal loss factor exhibitingtemperature characteristics that is estimated by damping test with a small sample. On theother hand, the sound reduction index of a solid glass depends strongly on boundarycondition due to less internal damping. The total loss factor of the test specimen includingthe internal losses and the edge losses were clarified based on the experimental results forvarious size and boundary condition. The sound reduction index of solid glass can beestimated for any size and thickness using boundary absorption coefficient of the glasspane. It is valuable to know the influence of edge damping to investigate the improvementof the sound reduction index for actual window assemblies.