抄録
In this paper, the authors are making systematic and experimental studies of a system, which generates the floor lmpact sound from actual floor slab, in order to determine quantitatively a relationship among various factors. As for the vibration characteristics of slab in the case of floor slab impact, the impedance characteristics under variable slab thickness, material, area, fixing etc. were investigated from various point of view by the application of the driving point impedance method for the time analysis. The impedance at the so-called forced response, corresponding to the impact time of an impact source was measured to consider the influence of the degree of slab edge fixing on the change in impedance characteristics at various impact points, and the whole time response was inquired to consider decrease in impedance at the frequency bands, which include fundamental and higher-order modes frequencies of the natural vibration, due to the decay time to vibration of slab. Distribution of the response velocity as a result of impact made on slab was determined to inquire into a possible relationship between this distribution and the effective sound radiating area. As for the sound radiation characteristics, the response to vibration as well as sound pressures directly under the excited point and in the directly lower room as a result of impact made on the slabs were determined to consider the correspondence of these three quantities from the time analysis result of the response waveform and at the same time to discuss the sound radiation resistance.
