Investigation of the Physical Mechanism of Walking Noise Radiation of Laminate Floor-Coverings

This paper reports on an investigation of the physical mechanism of walking noise radiated by laminate floor coverings with and without backings. In pretests of single laminate panels the influence of different backings on the structural vibration of the panels was determined and material parameters like Young's modulus and bending stiffness were obtained. From these parameters the coincidence frequency could be estimated. The main tests were performed with hard rubber balls falling on laminate floor coverings of different sizes and with different backings. Results show that the radiated sound has a single frequency maximum, which is far below the coincidence frequency. From this and from confirming sound intensity measurements it follows that the sound radiation is a locally constrained phenomenon. Additionally, vibration measurements show that the near field of bending waves dominates the vibration and bending wave propagation can be neglected. The characteristics of the near field vibration and therefore the sound radiation can be controlled by the choice of backing of the laminate floor covering.