Measurement of Acoustic Emission Wave by Using Optical Fiber Sensor during Microsecond Discharge

2008 ◽  
Vol 381-382 ◽  
pp. 399-402 ◽  
Author(s):  
Yoshiaki Akematsu ◽  
Atsutoshi Hirao ◽  
H. Takezawa ◽  
Kazuro Kageyama ◽  
Naotake Mohri ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Electrical Discharge ◽  
Optical Fiber Sensor ◽  
Electrical Current ◽  
Vibration Sensor ◽  
Fiber Sensor ◽  
Work Piece ◽  
Force Direction ◽  
Discharge Duration ◽  
Current Behavior

In this study, we investigate the effect of discharge current on the occurrence of burst AE wave caused by microsecond discharge. Electrical discharge duration was changed from about 1µs to 8µs by using condenser circuit. Effect of current behavior was estimated by comparing with experimental signal and simulation one. AE wave was detected by optical fiber vibration sensor. The optical fiber vibration sensor is located on an aluminum work-piece (cathode) plate. Simulation was carried out with MSC. Marc. As the results, it was found that AE wave was occurred by a force depending on electrical current behavior. The force direction was machining direction. The force has been occurred during microsecond discharge.

Effect of Discharge Condition on Cavitations Behavior by Single Pulse Discharge

2012 ◽  
Vol 523-524 ◽  
pp. 951-956
Author(s):  
Yoshiaki Akematsu ◽  
Kazuro Kageyama ◽  
Naotake Mohri ◽  
Hideaki Murayama
Keyword(s):  
Optical Fiber ◽  
Discharge Current ◽  
Electrical Discharge ◽  
Electrical Discharge Machining ◽  
Pulse Discharge ◽  
Optical Fiber Sensor ◽  
Single Pulse ◽  
Vibration Sensor ◽  
Work Piece ◽  
Discharge Condition

This paper describes some experimental results on a fundamental phenomenon of the single pulse discharge. In electrical discharge machining (EDM), processing accuracy was effected by behaviors of fused material. Pressure was important for removing fused material. So, it was needed to clarify that the mechanism of pressure occurrence by electrical discharge. In this study, it was investigated that effect of discharge condition on cavitations behavior by single pulse discharge. Gap region medium viscosity was changed by medium and temperature. Electrical discharge current was changed by applied voltage. The optical fiber vibration sensor is located on an aluminum work-piece (cathode) plate. Pressure was measured by optical fiber sensor during single pulse discharge. As the results, burst acoustic emission (AE) wave was occurred during single pulse discharge. The occurrence of several times burst AE wave was caused by cavitations behavior. The condition on which bubble does not collapse has become apparent. It was found that cavitations behavior was mainly depended on discharge current except for the condition on which bubble does not collapse.

Effect of Arc Discharge Pressure on Discharge Current in EDM

2008 ◽  
Vol 381-382 ◽  
pp. 451-454
Author(s):  
Atsutoshi Hirao ◽  
S. Tai ◽  
H. Takezawa ◽  
Naotake Mohri ◽  
Kazuro Kageyama ◽  
...  
Keyword(s):  
Discharge Current ◽  
Electrical Discharge ◽  
Material Removal ◽  
Electrical Discharge Machining ◽  
Arc Discharge ◽  
Vibration Sensor ◽  
Work Piece ◽  
Tool Electrode ◽  
Discharge Pressure ◽  
Current Behavior

In electrical discharge machining (EDM), an electrical discharge occurs between a tool electrode and a work-piece, and removal of materials is carried out by vaporized explosion between the electrode and the work-piece. However, the mechanism of material removal in EDM is not well understood. In order to clarify this issue, the acoustic emission (AE) method has been applied to examine the force of explosion, and the Schlieren visualization method has been applied to observe the explosion. In this study, we investigate the effect of discharge current behavior on the occurrence of the AE waves by means of an optical fiber vibration sensor.

Development of Smart Composite Panel with Optical Fiber Sensors

2005 ◽  
Vol 297-300 ◽  
pp. 659-664
Author(s):  
Hideaki Murayama ◽  
Kazuro Kageyama ◽  
Isamu Ohsawa ◽  
Makoto Kanai ◽  
Kiyhoshi Uzawa ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Composite Structures ◽  
Optical Fiber Sensor ◽  
Optical Fiber Sensors ◽  
Vibration Sensor ◽  
Composite Panel ◽  
Fiber Sensor ◽  
Smart Composite ◽  
Fiber Sensors ◽  
Distributed Sensors

We have developed a novel fiber-optic vibration sensors and applied commercially available strain and temperature sensors to health monitoring of composite structures. In this study, we constructed an optical fiber network integrating four types of optical fiber sensor into a carbon reinforced plastic (CFRP) panel. These four sensors were the vibration sensor developed by our laboratory, two distributed sensors based on Brillouin and Raman backscattering and Fiber Bragg Grating (FBG) sensors. By dealing the data obtained from the measurement systems corresponding to these four sensors, strain/stress and temperature distributions throughout the panel can be monitored. Vibration and elastic waves transmitting on the panel are also detected at several sensing points. Furthermore, we will be able to determine damage locations and modes by processing the wave signals. To make the panel with the optical fiber sensor network more sensitive and smarter, we are developing some techniques that can improve the performance of the sensors and can assess the structural integrity by analyzing measurement results. In this paper, the development of the first generation of our smart composite panel with the optical fiber sensors is described and the techniques making the panel more sensitive and smarter are also described.

DESIGN AND FABRICATION OF A NOVEL NONCONTACT VIBRATION SENSOR USING INCLINED-CUT OPTICAL FIBER

2008 ◽  
Vol 22 (11) ◽  
pp. 1177-1182
Author(s):  
KYONG-WOO KIM ◽  
WOO-SEONG CHE ◽  
HYU-SANG KWON
Keyword(s):  
Optical Fiber ◽  
Low Cost ◽  
Optical Fiber Sensor ◽  
High Sensitivity ◽  
Intensity Modulation ◽  
Vibration Sensor ◽  
Fiber Sensor ◽  
Electric Signal ◽  
Modulation Type ◽  
Low Sensitivity

This optical fiber sensors are being widely used alternative to conventional sensors in various applications because of small size, relatively light weight, high sensitivity and wide bandwidth. Also it has immunity to electromagnetic interferences, because of their dielectric, glass, or plastic nature, they are usually small and light, and they allow remote electric signal opto-electronic conversion and processing. In various uses of optical fiber, intensity modulation type sensor due to misalignment has practical usefulness because it can be realized in ease with low cost and simple structure. To overcome low sensitivity problem in intensity modulation type optical fiber sensor, inclined-cut optical fiber is considered here. Based on optical geometry, the inclined-cut optical fiber sensor is designed and fabricated. The experiments are carried out to evaluate sensor performance. The optical fiber sensor developed in this paper has sufficient precisions and therefore it is available to measure the vibration without contact.

Method of Measuring Tendon Force using Optical Fiber Sensor

2018 ◽  
Vol 56 (1) ◽  
pp. 94-99
Author(s):  
N. Sogabe ◽  
S. Nakaue ◽  
K. Chikiri ◽  
M. Hayakawa
Keyword(s):  
Optical Fiber ◽  
Optical Fiber Sensor ◽  
Fiber Sensor ◽  
Tendon Force

scholarly journals Oxygen concentration measurement in the porous cathode of a lithium-air battery using a fine optical fiber sensor

2019 ◽  
Vol 5 (0) ◽  
pp. 19-00095-19-00095
Author(s):  
Shogo FUJIMOTO ◽  
Suguru UEMURA ◽  
Nobuyuki IMANISHI ◽  
Shuichiro HIRAI
Keyword(s):  
Optical Fiber ◽  
Oxygen Concentration ◽  
Optical Fiber Sensor ◽  
Concentration Measurement ◽  
Fiber Sensor ◽  
Porous Cathode ◽  
Air Battery

scholarly journals Measurement Improvement of Distributed Optical Fiber Sensor via Lorenz Local Single Peak Fitting Algorithm

Symmetry ◽  
2021 ◽  
Vol 13 (7) ◽  
pp. 1166
Author(s):  
Bin Liu ◽  
Jianping He ◽  
Shihai Zhang ◽  
Yinping Zhang ◽  
Jianan Yu ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Frequency Shift ◽  
Optical Fiber Sensor ◽  
Gain Spectrum ◽  
Fiber Sensor ◽  
Peak Fitting ◽  
Fitting Algorithm ◽  
Distributed Optical Fiber Sensor ◽  
Brillouin Gain ◽  
Distributed Optical Fiber

Brillouin frequency shift (BFS) of distributed optical fiber sensor is extracted from the Brillouin gain spectrum (BGS), which is often characterized by Lorenz type. However, in the case of complex stress and optical fiber self damage, the BGS will deviate from Lorenz type and be asymmetric, which leads to the extraction error of BFS. In order to enhance the extraction accuracy of BFS, the Lorenz local single peak fitting algorithm was developed to fit the Brillouin gain spectrum curve, which can make the BSG symmetrical with respect to the Brillouin center frequency shift. One temperature test of a fiber-reinforced polymer (FRP) packaged sensor whose BSG curve is asymmetric was conducted to verify the idea. The results show that the local region curve of BSG processed by the developed algorithm has good symmetry, and the temperature measurement accuracy obtained by the developed algorithm is higher than that directly measured by demodulation equipment. Comparison with the reference temperature, the relative measurement error measured by the developed algorithm and BOTDA are within 4% and 8%, respectively.

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