PFI-TT: Multi-Frequency Acoustic Device for Rapid Infrastructure Damage Diagnostics

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The broader impact/commercial potential of this Partnerships for Innovation-Technology Translation (PFI-TT) project is to ensure the safe operation of critical civil infrastructure (such as pipelines and bridges) using a more reliable and cost-effective means of monitoring their health. Subjected to an increasing number and magnitude of extreme weather events, the performance of aging infrastructure is a concern; Unexpected failures cause significant disruption in transportation and negatively influence human lives and the environment. Fortunately, acoustic emission, can “listen” for cracks in the infrastructure and detect defects before they are visible. The innovation is to build a low-cost and low-power acoustic emission device for instrumenting infrastructures with hundreds of sensors and detecting the damage initiation at the earliest state. The technology for the sensors is micro-electro-mechanical systems, MEMS. Mass manufactured MEMS acoustic emission devices may take the technology to the next level by collecting big and reliable data from infrastructures. The aim is to instrument infrastructures with voluminous sensors that can rapidly inform about the structural state and safety. When the majority of structural systems in the US are instrumented with MEMS acoustic emission devices, the initiation of failure can be detected at its earliest stage and necessary precautions can be taken, preventing greater expenses. The proposed project aims to transition multi-frequency MEMS acoustic emission devices integrated with noise isolation capability into a field-deployable technology. Acoustic Emission is a nondestructive evaluation method based on detecting the propagating elastic waves due to active defects or movements such as crack growth or landslides. It is well-known for detecting the initiation of damage, pinpointing its location, qualitatively assessing the severity of damage, and classifying the damage mode using pattern recognition tools. However, current acoustic emission sensors are bulky, expensive, and significantly influenced by background noise; They require complex post-processing to understand the signal characterization, which delays the decision-making process. MEMS sensors are manufactured using micromachining techniques, that allow mass manufacturing with repeatable intrinsic characteristics. MEMS acoustic emission devices will be built by multiple super-narrow bandwidth MEMS piezoelectric resonators connected in an array such that the total response is amplified by the constructive interference of carefully selected frequencies. The signal can easily be decomposed into its frequencies in order to understand the frequency-dependent damage modes and severity. To distinguish artificial noise sources from active structural defects, the MEMS acoustic emission device will be coupled with broadband elastic metamaterials to block unwanted signals for the reduced-data wireless transfer.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.