Bettarello F., Fausti P., Bonfiglio P., Quiqueto G.

Standard ISO 9052-1 provides for the determination of the dynamic stiffness of materials used under floating floors in dwellings. The measurement technique is based on the determination of the resonant frequency of the fundamental vertical vibration of a spring and mass system realized in the test arrangement. The procedures consider the use of either sinusoidal, white noise or pulse signals. When, using the sinusoidal excitation signal, the tested material shows a dependence between the resonant frequency and the amplitude of the excitation force, a specific procedure is given in the standard. A similar procedure is not present in the pulse signal method, but also in this case the amplitude of the excitation pulse may affect the resonant frequency. In order to determine the correct value of the dynamic stiffness of the material also in case of pulse signals, a procedure is described and analyzed. The results acquired by using the impact excitation are compared to those obtained by using other techniques. This is done as part of the Inter-Laboratory Test on dynamic stiffness measurements according to the ISO 9052-1 standard, carried out by the AIA (Italian Acoustic Association).