Abstract
There are currently 730,000 bridges in Japan. Although in 2018, 25 % of the road bridges had more than 50 years old, an indicator of the aging of the transport infrastructure, this indicator will reach 63% in 2033. Furthermore, human resources, such as professional workers and engineers working on the inspection and maintenance, are gradually decreasing. Therefore, adequate inspection and maintenance are not always conducted; this is considered a serious social problem in Japan. To solve this problem, we have previously proposed a self-powered vibration-based structural health monitoring system. The core part of the system is the novel vibration-sensing device discussed, which implements a giant magnetostrictive material. In this paper, the structure of the sensor is investigated to solve the problems of the prototype device before. The bridge girder on which the sensor is installed is tilted by several degrees, so the pressure does not act evenly on the material. Therefore, we propose a structure using concave-convex spherical contact. The experimental results showed that the bending stress could be reduced and the generated power could be improved compared to the previous prototype sensor.
