Presentation	2005/1/20 Reproducibility Improvement of the LFB Ultrasonic Material Characterization System Yuji OHASHI, Jun-ichi KUSHIBIKI, Yuichi SHIRASAKI,
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Abstract(in English)	Measurement environment of temperature for the line-focus-beam ultrasonic material characterization (LFB-UMC) system is stabilized to improve its measurement accuracy for a long period of time. The measurement accuracy of the velocity of leaky surface acoustic waves (LSAWs), V_, obtained from analyzing the measured V(z) curve depends on the temperature stability in the water-couplant, according to the measurement principle. When the stepping motor for moving z-axis stage during the V(z) curve measurements (z motor) is driven, calorific value of the z motor becomes larger than that during stop because iron loss (hysteresis loss and eddy current loss) is generated in addition to Joule heat. Therefore, difference of calorific values from the motor between drive and stop disturbs the temperature environment, and results in decreasing the measurement accuracy of V_. To resolve this problem, we propose a method for making the z-motor temperature constant by compensating the heat corresponding to the iron loss with the current increased during stop of the z motor. Consequently, we can stabilize the measurement accuracy within ±0.0016% for V_ with ±0.134℃ for the z-motor temperature and ±0.012℃ for couplant temperature for 10 sets of measurements (1-set measurement consists consecutive 200 V(z) curves and a period of z-motor stop for 30 min.). We successfully realized the reliable system.
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Keyword(in English)	LFB ultrasonic material characterization system / leaky surface acoustic wave velocity / V(z) curve / control of heat generation from motors / water couplant temperature
Paper #	US2004-89
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Conference Information
Committee	US
Conference Date	2005/1/20(1days)
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Paper Information
Registration To	Ultrasonics (US)
Language	JPN
Title (in Japanese)	(See Japanese page)
Sub Title (in Japanese)	(See Japanese page)
Title (in English)	Reproducibility Improvement of the LFB Ultrasonic Material Characterization System
Sub Title (in English)
Keyword(1)	LFB ultrasonic material characterization system
Keyword(2)	leaky surface acoustic wave velocity
Keyword(3)	V(z) curve
Keyword(4)	control of heat generation from motors
Keyword(5)	water couplant temperature
1st Author's Name	Yuji OHASHI
1st Author's Affiliation	Graduate School of Engineering, Tohoku University()
2nd Author's Name	Jun-ichi KUSHIBIKI
2nd Author's Affiliation	Graduate School of Engineering, Tohoku University
3rd Author's Name	Yuichi SHIRASAKI
3rd Author's Affiliation	Marine Eco Tech Ltd.
Date	2005/1/20
Paper #	US2004-89
Volume (vol)	vol.104
Number (no)	612
Page	pp.pp.-
#Pages	6
Date of Issue