車両搭載型水撃音響試験装置の開発

抄録

An onboard water jet impact acoustic testing device has been developed. The interior unit consists of a water tank, a pomp, batteries and a DC-AC inverter. The unit on the roof of the vehicle consists of a water gun, a gun-microphone, and a video camera. The device discharges a water jet stream at concrete walls and collects the impact sound due to the water droplets. The speed of the water jet is changeable by changing the frequency of the DC-AC inverter. 300 mm square shallow defect could be detected at a distance of two meters while moving at one meter per second. The water jet had a speed of ten meters per second and a diameter of five millimeters.