Bio-inspired magnetostrictive whisker sensors for autonomous bridge scour sensing

This paper presents an ongoing study focused on scour detection using automated remote flow detection arrays based on bio-inspired magnetostrictive flow sensors. Whisker-shaped sensors made of Galfenol have previously been demonstrated to be effective flow sensors through the inherently large coupling that exists between stress and magnetic field within this material. As fluid flow causes the whisker to bend, the internal magnetic dipoles realign resulting in a measurable change in magnetic field at the base of the whisker. These sensors are inexpensive and robust versions of buried-rod scour sensors. This study employs these sensors to detect scour around bridge piers and abutments. Whiskers that are free to move in the water will return dynamic signals; whiskers trapped by sediment will return static signals. By interrogating the state of the array, a map of the channel bed can be inferred and communicated to a remote user via cellular data link and web client. The relative simplicity of this data interrogation contributes to the robustness of the system. Wireless “smart scour-sensing posts” are proposed as modular installations of multiple flow transducers coupled with data acquisition electronics for scour monitoring. A decision support framework to provide useful information to bridge owners is an integral part of the project. A robust program of validation is in progress to define the limits of the approach both in the laboratory and the field. Technical challenges such as corrosion protection signal classification, sensor fault detection, installation, and data and information flow and representation are explored