Fatigue Crack Closure Analysis Using Nonlinear Ultrasound

Tsuyoshi Mihara, Ryota Sasaki, Toshihiro Ogata, Kazushi Yamanaka
2004 The Proceedings of the Symposium on Evaluation and Diagnosis  
In order to analyze the crack closure of a fatigue crack, nonlinear ultrasound is applied. In introduction of fatigue crack we develop the crack opening monitoring procedures using TOFD method to obtain the reliable result about the relation between crack opening displacement and nonlinear ultrasound. Longitudinal ultrasonic wave of 6.4MHz in frequency with large amplitude incident to the three point bending aluminum alloy and SUS316 stainless steel specimen. Angle probe transducer fabricated
more » ... this experiment was used for a measurement of nonlinear ultrasound. As the results, remarkable subharmonics of 3.2 MHz in frequency was observed in both materials specimen of aluminum alloy and SUS316 stainless steel. However secondary superharmonics of 12.8 MHz was observed only in aluminum alloy specimen and detail of the behavior for each material was different. Mechanism of subharmonics was also investigated.
doi:10.1299/jsmesed.2004.3.104 fatcat:akuillkgrfhp5cqdrfwuprxzae