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论文类型：期刊论文

发表时间：2018-08-01

发表刊物：SMART MATERIALS AND STRUCTURES

收录刊物：SCIE

卷号：27

期号：8

ISSN号：0964-1726

关键字：smart rock; magnetic field; bridge scour; structural health monitoring; non-contact measurement

摘要：In this study, two types of smart rock were proposed to monitor bridge scour effect, including a direction-unknown (DU) smart rock and a direction-known (DK) smart rock. The DU smart rock is a concrete ball containing a cylindrical magnet, and the DK smart rock is also a concrete ball but contains a magnet whose direction is always pointing to the projected direction of the ambient magnetic field (AMF) in the horizontal plane. Based on the theory of magnetic field, the distribution of the magnetic field induced by DU and DK smart rock was derived. Algorithms were developed to localize the position of the two smart rocks under the AMF. Field tests were conducted at a bridge pier, and the intensity and direction of the AMF at the test site were measured by using a magnetometer and a home-made device, respectively. Results showed that presence of steel reinforcement and steel girders in the bridge changed the distribution of the geomagnetic field. The algorithms were able to localize the position of both the DU and the DK smart rocks with satisfied accuracy. Compared with the DU smart rock, the amount of calculation to localize DK smart rock was reduced. However, the measurement error was increased due to the instability of its direction from varying AMF caused by environmental factors such as passing vehicles on the bridge.