Localization of stationary source of floor vibration using steered response power method

It is sometimes necessary to locate the source of machinery-induced vibrations in buildings when the generated vibration exceeds the acceptable limits. The objective of this study is to localize stationary source of vibration using floor vibration measurements with the steered response power (SRP) method. While this method has been used in microphone array processing and acoustic imaging systems, this paper describes the first application of this method to surface wave vibrations in structures. Source locations are derived from shifted and summed version of received signals by accelerometers to search and find the maximum likelihood of source location. Similar to the time difference of arrival (TDOA) method, the accuracy of the estimate is degraded by the frequency dependent propagation speed and attenuation of concrete floor, which lead to changes in the shape of the received signals. However, the SRP method is more robust than TDOA. Additional processing steps will be applied to reduce the effect of the aforementioned issues. The accuracy of the SRP method is validated through series of experiments in a building. To estimate the wave propagation speed, which is needed for SRP method, cross-correlation is used to compute delays between received signals. The accuracy of this method depends on the location of the source on the bay. Experiments showed an average error of 1 m or less for a single bay with a size of approximately 13.4 by 8.2 m when the source is located at mid bay. The results for SRP method as well as its advantages and shortcomings are discussed.