This is the novel system for Pipe Wall Thickness measurement which is combined EAMT(Electro Magnetic Acoustic Transducer) and Optical Fiber Sensor. The conventional ultrasonic thickness me ter is using in pipe wall thickness measurement. However, it is necessary to remove a heat insulator from pipe line. A characteristic of this novel system is that it is possible to measur e without removing a heat insulator and on-line monitoring, because of measurement probe is attached between pipe surface and heat ins...
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Measurement of Pipe Wall Thinning by Ultra Acoustic Resonance technique using Optical Fiber

We have developed a newly sensing technique by which we can measure strain or temperature along an optical fiber with the high spa tial resolution of less than 1 mm. This fiber-optic distributed sensing technique is based on optical frequency domain reflectomet ry and it can map strain or temperature profiles along fiber Bragg grating. In this paper, the principle of this technique, distri buted strain sensing with the high spatial resolution and the applications to strain measurements of welded joints are...
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Study on Fiber-Optic Distributed Sensing Technique with High Spatial Resolution

FOD (Fiber Optical Doppler) sensor, that can measure elastic wave in wide-band frequency, has been developed, which utilizes Laser Doppler effect within an optical fiber. In particular, FOD sensor can detect Acoustic Emission (AE), which is a useful parameter to monitor in-situ damage at various industrial equipments. AE is caused mainly by very initial micro-crack within a structural material due to over-stress, material-aging, etc. When taking advantage of fiber-optics, that are long signal transmi...
英字タイトル:
Condition Monitoring and Damage Screening by Fiber-optic AE Sensor

FOD (Fiber Optical Doppler) sensor, that can measure elastic wave in wide-band frequency, has been inve nted and developed, which utilizes Laser Doppler effect within an optical fiber. In particular, FOD sen sor can detect acoustic emission (AE), which is sometimes very useful parameter to monitor in-situ dama ge at various equipments. Report herein is its measurement principle and its application for field use....
英字タイトル:
Condition Monitoring and Damage Screening by Fiber-optic AE Sensor

FOD (Fiber Optical Doppler) sensor, that can measure elastic wave in wide-band frequency, has been developed, which utilizes Laser Doppler effect within an optical fiber. In particular, FOD sensor can detect Acoustic Emission (AE), which is a useful parameter to monitor in-situ damage at various industrial equipments. AE is caused mainly by very initial micro-crack within a structural material due to over-stress, material-aging, etc. When taking advantage of fiber-optics, that are long signal transmis...
英字タイトル:
Condition Monitoring and Damage Screening by Fiber-optic AE Sensor

We demonstrated strain measurements of the 6 m-scale composite wing structure by means of optical frequency domain reflectometry (OFDR) using fiber Bragg grating (FBG) sensors. It was succeeded to measure continuous distributed strain of local position in the wing with a high spatial resolution of 0.6 mm using a 500 mm-length FBG. Divisional strain with a 100 mm-spacing along the wing was also measured using a 42 points-multiplexed FBG. We verified possibility of the strain measurement technique becau...
英字タイトル:
Damage detection by Optical Fiber Strain Sensor