Author ORCID Identifier

https://orcid.org/0000-0003-3018-4077

Year of Publication

2021

Degree Name

Doctor of Philosophy (PhD)

Document Type

Doctoral Dissertation

College

Engineering

Department/School/Program

Civil Engineering

First Advisor

Dr. Douglas Bradley Davis

Abstract

If the generated vibration in a building exceeds the acceptable limit design for a floor system, it is necessary to identify the source of vibration, a process known as localization. The objective of this study is the localization of stationary vibration sources, and the approach used is the steered response power (SRP) method. This method has already been shown to work well for wireless and acoustical applications to locate transmitter and sound sources, respectively. To the writer’s knowledge, this study is the first application of the SRP method to locate vibration sources using floor vibration measurements. However, because waves behave differently when propagated through a concrete floor as opposed to the air, this method has been significantly modified for the application presented herein.

The key and prerequisite parameter for most vibration-sensing-localization approaches is wave propagation speed (WPS). The accuracy of these approaches therefore depends on the accuracy of the WPS estimate. The WPS of a concrete floor system is a function of parameters with high variability due to the mechanical and dynamic properties of the floor. This makes the task of vibration-sensing-localization challenging for the aforementioned approaches. The SRP method has been employed because it is based on an algorithm to post-process all received signals together and such structural variability is less likely to affect the accuracy; therefore, the SRP method is more robust.

Most localization approaches are based on ideal wave propagation, e.g., constant propagation speed in all directions and vibration energy decreasing predictably as the source-sensor distance increases. However, such ideal propagation does not occur in many real-world structural systems such as a concrete floor. In this study, the WPS was estimated empirically in orthogonal directions using the cross-correlation function. The SRP method used herein was adopted to use the estimated WPS in orthogonal directions as an input parameter and then automatically interpolating the corresponding propagation speed for all other directions. This is another advantage of this method over existing methods.

The experiment was conducted on the second floor of a full-scale, concrete-framed building at the University of Kentucky. The WPS was estimated in orthogonal directions using an electrodynamic shaker and seven accelerometers. The shaker applied an excitation force and acted as the source of vibration, and the accelerometers were put in various locations on the floor and measured the response. Using the estimated WPS and corresponding measurement data, the SRP method was able to locate the vibration source within 2.0 m in a floor approximately 13.4 m by 8.4 m in size.

Digital Object Identifier (DOI)

https://doi.org/10.13023/etd.2021.368

Funding Information

My funding was provided by the Qatari National Research Fund 2016-2019.

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