構造物モニタリングのための超低消費電力アコースティック・エミッション振幅頻度分布センサー

抄録

Aging infrastructure has become an issue of social importance and there is a desire to use information and communication technology such as Internet of things (IoT) sensors to efficiently maintain and manage such infrastructure. This paper proposes a novel, ultra-low-power acoustic emission (AE) amplitude–frequency distribution sensor for monitoring the structural health of infrastructure. AE is a weak elastic wave generated by cracks, rubbing, and other damage in structural materials. The relationship between AE amplitude and frequency distribution is known as Gutenberg–Richter’s law, and its slope (the b-value) is considered an indicator of material integrity. The proposed sensor was designed to monitor changes in structural integrity by detecting b-value trends over a long period. We focused on two key points for application as an IoT sensor: ultra-low power consumption and long-distance wireless transmission. The wake-on AE algorithm, which wakes the sensor system when AE waves are generated by damage, enables AE sensing while consuming very little power. In addition, the unique analog–digital cooperative circuit technology successfully extracts AE features with less sampling. Meanwhile, statistical analysis at the sensor edge contributes to reduced data rates and allows for the use of low-power wide area networks for data transmission.