カドワキ　レン   Ren Kadowaki   門脇　廉    所属   追手門学院大学  理工学部 機械工学科    職種   准教授
発表年月日	2019/11
発表テーマ	A New Testing Method for Bolt Loosening with Transmitted Ultrasonic Pulse
会議名	Asia Pacific Vibration Conference 2019
学会区分	国際学会
発表形式	その他
国名	オーストラリア
開催地名	シドニー工科大学（オーストラリア，シドニー市）
開催期間	2019/11/18～2019/11/20
発表者・共同発表者	門脇 廉,井上 卓見,亀田 健太朗,大村 和久
概要	Diagnosis of the bolt loosening is an important testing in many fields. This study aims to develop a new non-destructive testing method for the bolt loosening us-ing ultrasonic pulse projected to the side of the bolt. This method focuses on a transmitted pulse which travels across the bolt. This paper represents a demon-stration of the proposed method and discusses its mechanism through a geomet-rical identification of the transmission paths of the ultrasonic pulses. In the basic experiment with an aluminum block and a stainless steel bolt, tightening torque of the bolt could be evaluated via the amplitude of the transmitted wave which con-sisted of two pulses. Especially, the second pulse was sensitive to the tightening torque. On the other hand, geometrically, we identified 6 transmission paths in the block. Especially, two paths of them were relatively long, and traveled across two load flanks, whose transmittance was strongly affected by the tightening torque. This result suggest that the two pulses which traveled along these paths corresponded with the second pulse in the experiment. And the proposed method is qualitatively demonstrated.