The impedance of a floor influences the way vibration and structure-borne sound is generated in, propagates through and radiates from floors. The impedance is the resistance in a building element to pass on acoustic waves, for example when a force excites the material. The impedance is the ratio between the force strength and the resulting vibrational speed. A commonly known method to determine the impedance of a material is by doing a measurement with an ‘impedance hammer’, a hammer that has a force sensor integrated in its head.
However, sometimes the impedance of the floor has to be known after pre-stressing the floor. The heel drop method is a known method. Instead of exciting the floor with a hammer, you use your own weight to pre-stress the material and then drop on your heels for excitation. Downside of this method is that the force with which the floor is excited is not exactly known. The heel drop plate with three integrated force sensors was developed to be able to perform a heel drop measurement and know the exact force with which the floor was excited. The heel drop plate has to meet several criteria, like weight and stiffness, to be able to use it for these kind of measurements. The heel drop plate is for example used for measuring the OS-RMS90, the parameter used in norms for vibrations in floors.
