Prof. Nobuo Takeda Profile

Prof. Nobuo Takeda

Chair, Div of Transdisciplinary Sciences at Univ of Tokyo

SPIE Involvement:

Author

Publications (79)

Proceedings Article | 23 April 2017 Paper

Optical fiber sensor-based life cycling monitoring and quality assessment of carbon fiber reinforced polymer matrix composite structures

N. Takeda, S. Minakuchi

Proceedings Volume 10323, 1032315 (2017) https://doi.org/10.1117/12.2272472

KEYWORDS: Composites, Sensors, Fiber Bragg gratings, Fiber optics sensors, Optical fibers, Carbon, Fiber optics, Fiber reinforced polymers, Aerospace engineering, Manufacturing

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Proceedings Article | 2 June 2014 Paper

Thermal strain along optical fiber in lightweight composite FOG : Brillouin-based distributed measurement and finite element analysis

Shu Minakuchi, Teruhisa Sanada, Nobuo Takeda, Shinji Mitani, Tadahito Mizutani, Yoshinobu Sasaki, Keisuke Shinozaki

Proceedings Volume 9157, 91572H (2014) https://doi.org/10.1117/12.2059717

KEYWORDS: Fiber optic gyroscopes, Optical fibers, Finite element methods, Glasses, Temperature metrology, Aluminum, Composites, Carbon, Silica, Aerospace engineering

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Proceedings Article | 17 April 2013 Paper

Life cycle strain monitoring of composite airframe structures by FBG sensors

I. Takahashi, K. Sekine, M. Kume, H. Takeya, S. Minakuchi, N. Takeda, K. Enomoto

Proceedings Volume 8695, 869512 (2013) https://doi.org/10.1117/12.2009073

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Optical fibers, Temperature metrology, Structural health monitoring, Adhesives, Reflection, Thermography, Inspection

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Proceedings Article | 6 April 2012 Paper

Structural health monitoring of CFRP airframe structures using fiber-optic-based strain mapping

I. Takahashi, K. Sekine, M. Kume, H. Takeya, Y. Iwahori, S. Minakuchi, N. Takeda, K. Enomoto

Proceedings Volume 8345, 834531 (2012) https://doi.org/10.1117/12.914226

KEYWORDS: Fiber Bragg gratings, Sensors, Structural health monitoring, Finite element methods, Skin, Composites, Optical fibers, Channel projecting optics, Numerical simulations, Adhesives

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Proceedings Article | 3 April 2012 Paper

Impact localization on a cylindrical plate by near-field beamforming analysis

Hayato Nakatani, Talieh Hajzargarbashi, Kaita Ito, Tribikram Kundu, Nobuo Takeda

Proceedings Volume 8345, 83450Y (2012) https://doi.org/10.1117/12.915010

KEYWORDS: Sensors, Aluminum, Wave plates, Beam analyzers, Acoustics, Wave propagation, Near field, Acoustic emission, Waveguides, Composites

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Proceedings Article | 31 January 2012 Paper

Smart aircraft composite structures with embedded small-diameter optical fiber sensors

Nobuo Takeda, Shu Minakuchi

Proceedings Volume 8351, 83510I (2012) https://doi.org/10.1117/12.915129

KEYWORDS: Composites, Optical fibers, Sensors, Fiber Bragg gratings, Fiber optics sensors, Aircraft structures, Sensing systems, Structural health monitoring, Damage detection, Skin

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Proceedings Article | 14 April 2011 Paper

Life cycle strain mapping of composite airframe structures by using FBG sensors

K. Sekine, I. Takahashi, M. Kume, H. Takeya, Y. Iwahori, S. Minakuchi, N. Takeda, Y. Koshioka

Proceedings Volume 7981, 79812K (2011) https://doi.org/10.1117/12.879882

KEYWORDS: Sensors, Fiber Bragg gratings, Composites, Structural health monitoring, Distortion, Thermography, Carbon, Fiber reinforced polymers, Aerospace engineering, Materials processing

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Proceedings Article | 14 April 2011 Paper

Detecting the point of impact on a cylindrical plate by the acoustic emission technique

Talieh Hajzargarbashi, Hayato Nakatani, Tribikram Kundu, Nobuo Takeda

Proceedings Volume 7981, 79810U (2011) https://doi.org/10.1117/12.881199

KEYWORDS: Sensors, Acoustic emission, Wave plates, Aluminum, Wave propagation, Stars, Civil engineering, Acoustics, Genetic algorithms, Interference (communication)

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Proceedings Article | 1 April 2011 Paper

Hierarchical fiber-optic-based sensing system for impact damage monitoring of large-scale CFRP structures

Shu Minakuchi, Nobuo Takeda, Haruka Tsukamoto, Hidehiko Banshoya

Proceedings Volume 7984, 798427 (2011) https://doi.org/10.1117/12.880669

KEYWORDS: Sensors, Optical fibers, Sensing systems, Fiber optics, Fiber optics sensors, Damage detection, Polymers, Composites, Optical networks, Fiber optic networks

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Proceedings Article | 30 March 2011 Paper

Memorization and detection of an arrested crack in a foam-core sandwich structure using a crack arrester with embedded metal wires and FBG sensors

Shu Minakuchi, Nobuo Takeda, Ippei Yamauchi, Yasuo Hirose

Proceedings Volume 7982, 798204 (2011) https://doi.org/10.1117/12.880673

KEYWORDS: Sensors, Fiber Bragg gratings, Foam, Interfaces, Metals, Finite element methods, Lead, Optical fibers, Reflection, Tolerancing

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Proceedings Article | 1 April 2010 Paper

Life cycle structural health monitoring of airframe structures by strain mapping using FBG sensors

I. Takahashi, K. Sekine, H. Takeya, Y. Iwahori, N. Takeda, Y. Koshioka

Proceedings Volume 7647, 764723 (2010) https://doi.org/10.1117/12.847262

KEYWORDS: Fiber Bragg gratings, Sensors, Structural health monitoring, Composites, Skin, Damage detection, Temperature metrology, Optical fibers, Optical testing, Finite element methods

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Proceedings Article | 7 April 2009 Paper

Shape reconstruction of composite structures with monitoring of modeling changes using Brillouin scattering based distributed optical fiber strain sensor network

Mayuko Nishio, Nobuo Takeda

Proceedings Volume 7293, 729314 (2009) https://doi.org/10.1117/12.815606

KEYWORDS: Optical fibers, Reconstruction algorithms, Data modeling, Composites, Optical networks, Detection and tracking algorithms, Finite element methods, Light scattering, Scattering, Lithium

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Proceedings Article | 7 April 2009 Paper

Verification of the impact damage detection system for airframe structures using optical fiber sensors

Noriyoshi Hirano, Hiroaki Tsutsui, Junichi Kimoto, Takahiko Akatsuka, Hirofumi Sashikuma, Nobuo Takeda, Yasuhiro Koshioka

Proceedings Volume 7293, 72930Q (2009) https://doi.org/10.1117/12.817499

KEYWORDS: Optical fibers, Sensors, Composites, Fiber Bragg gratings, Fiber optics sensors, Damage detection, Reliability, Connectors, Structured optical fibers, Inspection

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Proceedings Article | 7 April 2009 Paper

Hierarchical structural health monitoring system combining a fiber optic spinal cord network and distributed nerve cell devices

Shu Minakuchi, Haruka Tsukamoto, Nobuo Takeda

Proceedings Volume 7293, 72930G (2009) https://doi.org/10.1117/12.815581

KEYWORDS: Optical fibers, Sensors, Sensing systems, Nerve, Composites, Optical networks, Fiber optics sensors, Damage detection, Fiber optics, Spinal cord

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Proceedings Article | 8 April 2008 Paper

Shape identification of variously-deformed composite laminates using Brillouin type distributed strain sensing system with embedded optical fibers

M. Nishio, T. Mizutani, N. Takeda

Proceedings Volume 6932, 69322P (2008) https://doi.org/10.1117/12.775671

KEYWORDS: Optical fibers, Reconstruction algorithms, Composites, Optical networks, Sensing systems, Sensors, Light scattering, Optical fabrication, Error analysis, Scattering

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Proceedings Article | 8 April 2008 Paper

Demonstration of detectability of SHM system with FBG/PZT hybrid system in composite wing box structure

Hideki Soejima, Toshimichi Ogisu, Hiroshi Yoneda, Yoji Okabe, Nobuo Takeda, Yasuhiro Koshioka

Proceedings Volume 6932, 69322E (2008) https://doi.org/10.1117/12.776078

KEYWORDS: Sensors, Fiber Bragg gratings, Ferroelectric materials, Structural health monitoring, Composites, Connectors, Aircraft structures, Inspection, Actuators, Skin

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Proceedings Article | 7 April 2008 Paper

Improvement of FBG/PZT hybrid sensing system for composite materials

Shinji Komatsuzaki, Seiji Kojima, Akihito Hongo, Nobuo Takeda, Yasuhiro Koshioka

Proceedings Volume 6933, 69330A (2008) https://doi.org/10.1117/12.776079

KEYWORDS: Sensors, Fiber Bragg gratings, Actuators, Ferroelectric materials, Composites, Sensing systems, Damage detection, Signal detection, Signal generators, Lead

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Proceedings Article | 7 April 2008 Paper

Research and development of impact damage detection system for airframe structures using optical fiber sensors

Hiroaki Tsutsui, Noriyoshi Hirano, Junichi Kimoto, Takahiko Akatsuka, Hirofumi Sashikuma, Nobuo Takeda, Naoyuki Tajima

Proceedings Volume 6933, 69330P (2008) https://doi.org/10.1117/12.776103

KEYWORDS: Optical fibers, Composites, Fiber optics sensors, Sensors, Damage detection, Fiber Bragg gratings, Connectors, Skin, Inspection, Optics manufacturing

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Proceedings Article | 27 March 2008 Paper

Fiber optic sensor-based SHM technologies for aerospace applications in Japan

Nobuo Takeda

Proceedings Volume 6933, 693302 (2008) https://doi.org/10.1117/12.776838

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Optical fibers, Structural health monitoring, Fiber optics sensors, Aerospace engineering, Reflection, Sensing systems, Fiber optics

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Proceedings Article | 19 March 2008 Paper

Development of highly reliable advanced grid structure (HRAGS) demonstrator using FBG sensors

H. Takeya, K. Sekine, M. Kume, T. Ozaki, N. Takeda, N. Tajima

Proceedings Volume 6930, 69300M (2008) https://doi.org/10.1117/12.775732

KEYWORDS: Fiber Bragg gratings, Sensors, Aircraft structures, Skin, Composites, Damage detection, Optical fibers, Aluminum, Optical components, Metals

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Proceedings Article | 11 April 2007 Paper

Impact monitoring of the aircraft composite structure using FBG sensor/PZT actuator hybrid sensor system

Noritsugu Nakamura, Toshimichi Ogisu, Hiroshi Yoneda, Yoji Okabe, Nobuo Takeda, Tateo Sakurai

Proceedings Volume 6527, 65270B (2007) https://doi.org/10.1117/12.715584

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Actuators, Aircraft structures, Ferroelectric materials, Structural health monitoring, Optical filters, Optical fibers, Reflection

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Proceedings Article | 10 April 2007 Paper

Structural shape identification using distributed strain data from PPP-BOTDA

M. Nishio, T. Mizutani, N. Takeda

Proceedings Volume 6530, 65301J (2007) https://doi.org/10.1117/12.715342

KEYWORDS: Optical fibers, Composites, Spatial resolution, Sensors, Structural health monitoring, Fiber optics sensors, Sensing systems, Carbon, Estimation theory, Aircraft structures

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Proceedings Article | 10 April 2007 Paper

Guided wave diagnosis in composite grid structure with embedded FBG sensors

Masataro Amano, Takeo Arai, Nobuo Takeda

Proceedings Volume 6530, 65300P (2007) https://doi.org/10.1117/12.717582

KEYWORDS: Fiber Bragg gratings, Sensors, Silver, Transducers, Waveguides, Structural health monitoring, Wave propagation, Skin, Composites, Multiplexing

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Proceedings Article | 10 April 2007 Paper

Small-diameter optical fiber and high-speed wavelength interrogator for FBG/PZT hybrid sensing system

Shinji Komatsuzaki, Seiji Kojima, Akihito Hongo, Nobuo Takeda, Takeo Sakurai

Proceedings Volume 6530, 65300O (2007) https://doi.org/10.1117/12.715900

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Optical fibers, Sensing systems, Signal attenuation, Actuators, Ferroelectric materials, Refractive index, Cladding

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We have been developing a sensing system for checking the health of aircraft structures made of composite materials. In this system, lead zirconium titanate (PZT) actuators generate elastic waves that travel through the composite material and are received by embedded fiber Bragg grating (FBG) sensors. By analyzing the change in received waveforms, we can detect various kinds of damage. The frequency of the elastic waves is several hundred kHz, which is too high for a conventional optical spectrum analyzer to detect the wavelength change. Moreover, a conventional single-mode optical fiber cannot be used for an embedded FBG sensor because it is so thick that it induces defects in the composite material structure when it is embedded. We are thus developing a wavelength interrogator with an arrayed waveguide grating (AWG) that can detect the high-speed wavelength change and a small-diameter optical fiber (cladding diameter of 40µm) that does not induce defects. We use an AWG to convert the wavelength change into an output power change by using the wavelength dependency of the AWG transmittance. For this conversion, we previously used two adjacent output ports that cover the reflection spectrum of an FBG sensor. However, this requires controlling the temperature of the AWG because the ratio of the optical power change to the wavelength change is very sensitive to the relationship of the center wavelengths between an FBG sensor and the output ports of the AWG. We have now investigated the use of a denser AWG and six adjacent output ports, which covers the reflection spectrum of an FBG sensor, for detecting the elastic waves. Experimental results showed that this method can suppress the sensitivity of the power change ratio to the relationship of the center wavelengths between an FBG sensor and the output ports. Although our improved small-diameter optical fiber does not induce structural defects in the composite material when it is embedded, there is some micro or macro bending of the fiber, which causes propagation loss. To suppress this embedment loss, we adjusted the refractive index difference of the fiber to have larger value. Experimental result showed that this reduced the embedment loss by about 0.3 dB/cm. These enhancements make our sensing system more practical and should promote the use of composite materials in a wider range of applications.

Proceedings Article | 22 December 2006 Paper

Highly reliable advanced grid structures (HRAGS) for aircraft structures using multi-point FBG sensor

H. Takeya, K. Sekine, M. Kume, T. Ozaki, N. Takeda, N. Tajima

Proceedings Volume 6413, 641306 (2006) https://doi.org/10.1117/12.695634

KEYWORDS: Fiber Bragg gratings, Sensors, Skin, Aircraft structures, Optical fibers, Optics manufacturing, Composites, Reliability, Optical switching, Damage detection

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Proceedings Article | 5 April 2006 Paper

Design and testing of integrated Bragg grating sensor systems for advanced grid structure

Masataro Amano, Tadahito Mizutani, Yoji Okabe, Nobuo Takeda, Tsuyoshi Ozaki

Proceedings Volume 6173, 61731C (2006) https://doi.org/10.1117/12.658127

KEYWORDS: Silver, Fiber Bragg gratings, Structural health monitoring, Sensors, Statistical analysis, 3D modeling, Finite element methods, Damage detection, Multiplexing, Signal detection

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Proceedings Article | 30 March 2006 Paper

Development of small-diameter optical fiber sensors and high-speed optical wavelength interrogator for damage detection in composite materials

Shinji Komatsuzaki, Seiji Kojima, Akihito Hongo, Nobuo Takeda, Tateo Sakurai

Proceedings Volume 6167, 616703 (2006) https://doi.org/10.1117/12.657796

KEYWORDS: Optical fibers, Fiber Bragg gratings, Sensors, Refractive index, Composites, Actuators, Ferroelectric materials, Connectors, Cladding, Sensing systems

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We have been developing a sensing system for monitoring the structural health of aircraft structures made of composite materials. The sensing system is composed of fiber Bragg grating (FBG) sensors, a wavelength interrogator and piezoelectric actuators. The FBG sensors receive 100 kHz to 1 MHz elastic waves generated by the PZT actuators. For the FBG sensors, we previously developed a polyimide-coated optical fiber with a cladding diameter of 40 μm and core-cladding relative refractive index difference Δ of 0.65 %, that can be embedded in composite materials without inducing any mechanical defects. Since the cladding of that fiber is so thin, however, under embedded conditions, the transmission loss of the fiber is larger than that of a normal single-mode optical fiber. We therefore developed a new small-diameter optical fiber with an Δ of 1.8 %, in order to suppress the loss increase caused by micro-bending or transversely applied strain under the embedded condition. On the other hand, the small-diameter optical fiber needs to be connected to a normal optical fiber whose claddingding diameter is 125 μm, because it is fragile and difficult to handle. For practical use, we developed a small-diameter optical fiber module that has a special connector on both ends of the small-diameter optical fiber. The special connector can connect the small-diameter optical fiber to a normal optical fiber that has a standard MU connector. We also developed a high-speed optical wavelength interrogator that can detect the high-frequency vibration of the FBG sensors. It uses an arrayed waveguide grating (AWG) as an optical filter that converts the wavelength shift of the light reflected from the FBG into the output optical power changes. This wavelength interogator is suiatable for high-speed wavelength detection because it has no mechanical moving parts. The development of these components will help put this system to practical use and thus extend the use of composite materials to a wider range of applications.

Proceedings Article | 30 March 2006 Paper

Damage growth monitoring for a bonding layer of the aircraft bonding structure

Toshimichi Ogisu, Masakazu Shimanuki, Hiroshi Yoneda, Yoji Okabe, Junichiro Kuwahara, Nobuo Takeda, Tateo Sakurai

Proceedings Volume 6171, 61710C (2006) https://doi.org/10.1117/12.658555

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Ferroelectric materials, Optical fibers, Fiber optics sensors, Structural health monitoring, Interfaces, Wave propagation, Optical components

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Proceedings Article | 30 March 2006 Paper

Damage detection of advanced grid structure using multipoint FBG sensors

H. Takeya, T. Ozaki, N. Takeda, N. Tajima

Proceedings Volume 6171, 61710D (2006) https://doi.org/10.1117/12.654375

KEYWORDS: Fiber Bragg gratings, Sensors, Damage detection, Tolerancing, Optical fibers, Aircraft structures, Composites, Structural health monitoring, Analytical research, Manufacturing

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Proceedings Article | 16 March 2006 Paper

Evaluation of debonding progress in composite bonded structures by ultrasonic wave sensing with fiber Bragg grating sensors

Yoji Okabe, Junichiro Kuwahara, Nobuo Takeda, Toshimichi Ogisu, Seiji Kojima, Shinji Komatsuzaki

Proceedings Volume 6179, 61790G (2006) https://doi.org/10.1117/12.657510

KEYWORDS: Fiber Bragg gratings, Sensors, Ultrasonics, Adhesives, Wave propagation, Wavelet transforms, Skin, Actuators, Wavelets, Optical filters

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Proceedings Article | 23 May 2005 Paper

Joining techniques for small-diameter optical fiber used in embedded sensor

Seiji Kojima, Sinji Komatsuzaki, Akihito Hongo, Nobuo Takeda, Tateo Sakurai

Proceedings Volume 5855, (2005) https://doi.org/10.1117/12.623628

KEYWORDS: Optical fibers, Sensors, Composites, Connectors, Fiber Bragg gratings, Cladding, Coating, Refractive index, Structured optical fibers, Zirconium dioxide

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Proceedings Article | 17 May 2005 Paper

Identification of damage location in advanced grid structures using fiber Bragg grating sensor

Masataro Amano, Ichiya Takahashi, Yoji Okabe, Nobuo Takeda, Hajime Takeya, Tsuyoshi Ozaki

Proceedings Volume 5765, (2005) https://doi.org/10.1117/12.599227

KEYWORDS: Fiber Bragg gratings, Sensors, Silver, Electronic support measures, Skin, Scanning electron microscopy, Finite element methods, Composites, Analytical research, Matrices

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Proceedings Article | 16 May 2005 Paper

Damage growth detection of composite laminate using embedded FBG sensor/PZT actuator hybrid system

Toshimichi Ogisu, Masakazu Shimanuki, Satoshi Kiyoshima, Yoji Okabe, Nobuo Takeda

Proceedings Volume 5758, (2005) https://doi.org/10.1117/12.598085

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Actuators, Fiber optics sensors, Ferroelectric materials, Structural health monitoring, Aircraft structures, Interfaces, Optical fibers

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This paper presents a part of the study conducted for developing a damage diagnostic system for an advanced composite material that can be utilized in next-generation aircraft structure. The authors have been working on a detection of elastic wave which can be launched from the PZT actuators, using small- and normal-diameter FBG optical fiber sensors that are bonded to the surface of the CFRP laminate under different conditions. Based on the results, it was verified that it is possible to achieve a high-accuracy detection of elastic wave by using FBG sensors bonded to the surface of the CFRP laminate. It was also verified that the damages generated on the inside of the composite material may be detected by the waveform analysis of the received elastic wave. In this study, the authors succeeded in the embedment of small-diameter FBG optical fiber sensors into the bonding surface of the double-lap type coupon specimen, which simulates the bonding structure of the CFRP composite structure. In this study, we also clarified several issues pertaining to the conditions, methods, and techniques involved in fiber embedding. An optical loss was observed during the embedment process, which may result in the loss of both accuracy and reliability. Based on these observations, the authors developed embedding techniques for optical fiber sensors that can reduce this optical loss. Additionally, the possibility of detecting an elastic wave, which was launched from the PZT actuators bonded to the surface of the coupon and directed to the host material, was verified using double-lap type coupon specimen having embedded small-diameter FBG optical fiber sensors at the bonding surface. Therefore, this specimen has provided an artificial defect that simulates the delamination generated at the bonding interface. Based on the measurements of the elastic wave, it was verified that the change in the elastic wave depends on the damage length, which is caused by the artificial defect. Moreover, based on the analysis of the received elastic wave, the possibility of damage detection was confirmed. The successful development of this damage monitoring system would ease the implementation of structural health monitoring system in aircraft structures in the near future.

Proceedings Article | 16 May 2005 Paper

Development of high-speed optical wavelength interrogation system for damage detection in composite materials

Shinji Komatsuzaki, Seiji Kojima, Akihito Hongo, Nobuo Takeda, Takeo Sakurai

Proceedings Volume 5758, (2005) https://doi.org/10.1117/12.599391

KEYWORDS: Fiber Bragg gratings, Composites, Sensors, Sensing systems, Ferroelectric materials, Wave propagation, Wave plates, Actuators, Optical filters, Optical fibers

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Proceedings Article | 16 May 2005 Paper

Lamb wave sensing using fiber Bragg grating sensors for delamination detection in composite laminates

N. Takeda, Y. Okabe, J. Kuwahara, S. Kojima

Proceedings Volume 5758, (2005) https://doi.org/10.1117/12.598594

KEYWORDS: Fiber Bragg gratings, Sensors, Ultrasonics, Wave propagation, Actuators, Wave sensors, Wave plates, Optical filters, Composites, Damage detection

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Proceedings Article | 16 May 2005 Paper

Identification of impact damage in sandwich structures by application of high speed MEMS-OSA to FBG sensors

Y. Okabe, S. Minakuchi, N. Takeda

Proceedings Volume 5758, (2005) https://doi.org/10.1117/12.598333

KEYWORDS: Fiber Bragg gratings, Sensors, Reflection, Optical fibers, Adhesives, Mirrors, Aluminum, Skin, Spectrum analysis, Fiber optics sensors

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Proceedings Article | 5 May 2005 Paper

Structural health monitoring of advanced grid structure using multipoint FBG sensors

H. Takeya, T. Ozaki, N. Takeda

Proceedings Volume 5762, (2005) https://doi.org/10.1117/12.598759

KEYWORDS: Fiber Bragg gratings, Sensors, Optical fibers, Structural health monitoring, Sensor networks, Aircraft structures, Composites, Optics manufacturing, Transmittance, Optical fabrication

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Proceedings Article | 29 July 2004 Paper

Development of damage monitoring system for aircraft structure using a PZT actuator/FBG sensor hybrid system

Toshimichi Ogisu, Masakazu Shimanuki, Satoshi Kiyoshima, Yoji Okabe, Nobuo Takeda

Proceedings Volume 5388, (2004) https://doi.org/10.1117/12.539727

KEYWORDS: Sensors, Fiber Bragg gratings, Composites, Ferroelectric materials, Aircraft structures, Actuators, Fiber optics sensors, Electronic filtering, Aluminum, Reliability

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This paper presents a part of the research results on a damage monitoring system using PZT actuators/FBG sensors for advanced composite material structures of new-generation aircrafts. To achieve weight reduction of the aircraft structure, these advanced composite materials have gradually been employed for the primary structure. It is expected that when these materials are extensively employed, an efficient bonded structure such as a hat-shaped stringer will be utilized for the aircraft structure. However, these bonded structures have critical problems such as debonding and delamination at the interfaces of the laminate. Further, a single-step molding process of the structure elements is necessary in order to ensure low cost and thus affordability. However, this low-cost process results in an increase in the non-destructive inspection (NDI) cost. Therefore, an innovative damage monitoring system is required for structural health management. In the present study, the authors have developed a hybrid sensor system that can detect the elastic waves launched from the piezo transducer (PZT) actuator using a high-speed and high-accuracy fiber Bragg grating (FBG) sensor to resolve the issues mentioned above. In this study, the conceptual design of an aircraft that can employ this damage monitoring system was carried out. Subsequently, the application area was selected based on cases of certain kinds of damage. Further, the validity of the damage monitoring system for the verification of the structural integrity of the aircraft was discussed. Next, in order to verify the elastic wave detectability of the FBG sensor, it was confirmed that an elastic wave of 300 kHz is detectable at a distance of 5 cm between the PZT actuator and FBG sensor using an aluminum sheet and CFRP cross-ply laminate and also by considering the relationship between sensor length and sensitivity. Through the present research results, the possibility of applying the damage monitoring system to the composite material bonding structure in an aircraft is presented.

Proceedings Article | 27 July 2004 Paper

High-speed optical wavelength interrogator using a PLC-type optical filter for fiber Bragg grating sensors

Seiji Kojima, Akihito Hongo, Shinji Komatsuzaki, Nobuo Takeda

Proceedings Volume 5384, (2004) https://doi.org/10.1117/12.539427

KEYWORDS: Fiber Bragg gratings, Sensors, Optical filters, Ferroelectric materials, Sensing systems, Composites, Photonic integrated circuits, Actuators, Silica, Defect detection

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Proceedings Article | 26 July 2004 Paper

Debonding monitoring of a composite repair patch using small-diameter FBG sensors

Shin-ichi Takeda, Takeharu Yamamoto, Yoji Okabe, Nobuo Takeda

Proceedings Volume 5390, (2004) https://doi.org/10.1117/12.539722

KEYWORDS: Fiber Bragg gratings, Sensors, Adhesives, Aluminum, Composites, Reflection, Thermography, Carbon, Structured optical fibers, Photography

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Proceedings Article | 18 August 2003 Paper

Structural health monitoring system using FBG-based sensors for a damage-tolerant building

Hideaki Iwaki, Keiji Shiba, Nobuo Takeda

Proceedings Volume 5057, (2003) https://doi.org/10.1117/12.482701

KEYWORDS: Sensors, Structural health monitoring, Earthquakes, Fiber optics sensors, Fiber Bragg gratings, Metals, Refractive index, Coating, Internet, Safety

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Proceedings Article | 14 August 2003 Paper

Damage suppression system using embedded SMA (shape memory alloy) foils in CFRP laminate structures

Toshimichi Ogisu, Masakazu Shimanuki, Satoshi Kiyoshima, Junji Takaki, Nobuo Takeda

Proceedings Volume 5054, (2003) https://doi.org/10.1117/12.483882

KEYWORDS: Shape memory alloys, Smart materials, Actuators, Aircraft structures, Embedded systems, Manufacturing, Aluminum, Structural health monitoring, Skin, Radon

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Proceedings Article | 14 August 2003 Paper

Impact damage detection system using small-diameter optical fiber sensors wavily embedded in CFRP laminate structures

Hiroaki Tsutsui, Akio Kawamata, Junichi Kimoto, Akira Isoe, Yasuo Hirose, Tomio Sanda, Nobuo Takeda

Proceedings Volume 5054, (2003) https://doi.org/10.1117/12.483874

KEYWORDS: Damage detection, Composites, Optical fibers, Sensors, Fiber optics sensors, Skin, Fiber Bragg gratings, Optical testing, Visualization, Connectors

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Proceedings Article | 14 August 2003 Paper

Overview of demonstrator program of Japanese Smart Materials and Structure System project

Naoyuki Tajima, Tateo Sakurai, Mikio Sasajima, Nobuo Takeda, Teruo Kishi

Proceedings Volume 5054, (2003) https://doi.org/10.1117/12.483721

KEYWORDS: Damage detection, Composites, Actuators, Smart materials, Shape memory alloys, Skin, Optics manufacturing, Fiber optics sensors, Ferroelectric materials, Sensors

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The Japanese Smart Material and Structure System Project started in 1998 as five years' program that funded by METI (Ministry of Economy, Trade and Industry) and supported by NEDO (New Energy and Industrial Technology Development Organization). Total budget of five years was finally about 3.8 billion Japanese yen. This project has been conducted as the Academic Institutions Centered Program, namely, one of collaborated research and development among seven universities (include one foreign university), seventeen Industries (include two foreign companies), and three national laboratories. At first, this project consisted of four research groups that were structural health monitoring, smart manufacturing, active/adaptive structures, and actuator material/devices. Two years later, we decided that two demonstrator programs should be added in order to integrate the developed sensor and actuator element into the smart structure system and verify the research and development results of above four research groups. The application target of these demonstrators was focused to the airplane, and two demonstrators that these shapes simulate to the fuselage of small commercial airplane (for example, Boeing B737) had been established. Both demonstrators are cylindrical structures with 1.5 m in diameter and 3 m in length that the first demonstrator has CFRP skin-stringer and the second one has CFRP skin. The first demonstrator integrates the following six innovative techniques: (1) impact monitoring using embedded small diameter optical fiber sensors newly developed in this program, (2) impact monitoring using the integrated acoustic emission (AE) systems, (3) whole-field strain mapping using the BOTDR/FBG integrated system, (4) damage suppression using embedded shape memory alloy (SMA) films, (5) maximum and cyclic strain sensing using smart composite patches, and (6) smart manufacturing using the integrated sensing system. The second one is for demonstrating the suppression of vibration and acoustic noise generated in the composite cylindrical structure. In this program, High-performance PZT actuators/sensors developed in this program are also installed. The whole tests and evaluations have now been finished. This paper presents the outline of demonstrator programs, followed by six presentations that show the detail verification results of industrial demonstration themes.

Proceedings Article | 14 August 2003 Paper

Overview of damage detection and damage suppression demonstrator and strain distribution measurement using distributed BOTDR sensors

Takashi Yari, Kanehiro Nagai, Takayuki Shimizu, Nobuo Takeda

Proceedings Volume 5054, (2003) https://doi.org/10.1117/12.483868

KEYWORDS: Spatial resolution, Fiber optics sensors, Fiber Bragg gratings, Temperature metrology, Sensors, Optical fibers, Composites, Aerospace engineering, Wavelength division multiplexing, Damage detection

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Proceedings Article | 5 August 2003 Paper

Application of fiber Bragg grating sensors to real-time strain measurement of cryogenic tanks

Nobuo Takeda, Tadahito Mizutani, Kentaro Hayashi, Yoji Okabe

Proceedings Volume 5056, (2003) https://doi.org/10.1117/12.483406

KEYWORDS: Sensors, Fiber Bragg gratings, Cryogenics, Composites, Adhesives, Liquids, Temperature metrology, Polyurethane, Reflection, Optical fibers

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Proceedings Article | 22 July 2003 Paper

Application of chirped FBG sensors for detection of local delamination in composite laminates

Shin-ichi Takeda, Yoji Okabe, Nobuo Takeda

Proceedings Volume 5050, (2003) https://doi.org/10.1117/12.484243

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Refractive index, Optical fibers, Carbon, Spectrum analysis, Smart materials, Wave propagation, Cladding

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Proceedings Article | 22 July 2003 Paper

Embedded small-diameter fiber Bragg grating sensors and high-speed wavelength detection

Akihito Hongo, Keisuke Fukuchi, Seiji Kojima, Nobuo Takeda

Proceedings Volume 5050, (2003) https://doi.org/10.1117/12.484249

KEYWORDS: Fiber Bragg gratings, Optical fibers, Sensors, Wavelength division multiplexing, Composites, Reflection, Cladding, Photonic integrated circuits, Connectors, Coating

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Proceedings Article | 15 July 2002 Paper

Progress in demonstrator program of Japanese Smart Material and Structure System Project

Naoyuki Tajima, Tateo Sakurai, Nobuo Takeda, Teruo Kishi

Proceedings Volume 4701, (2002) https://doi.org/10.1117/12.474651

KEYWORDS: Damage detection, Actuators, Composites, Smart materials, Shape memory alloys, Sensors, Ferroelectric materials, Skin, Manufacturing, Optics manufacturing

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Proceedings Article | 9 July 2002 Paper

Impact damage detection of curved stiffened composite panels by using wavy embedded small-diameter optical fibers

Hiroaki Tsutsui, Akio Kawamata, Junichi Kimoto, Tomio Sanda, Nobuo Takeda

Proceedings Volume 4698, (2002) https://doi.org/10.1117/12.475090

KEYWORDS: Optical fibers, Composites, Sensors, Fiber Bragg gratings, Fiber optics sensors, Damage detection, Skin, Optics manufacturing, Inspection, Optical testing

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Proceedings Article | 9 July 2002 Paper

Application study on aircraft structures of CFRP laminates with embedded SMA foils

Toshimichi Ogisu, Masato Nomura, Norio Ando, Junji Takaki, Nobuo Takeda

Proceedings Volume 4698, (2002) https://doi.org/10.1117/12.475085

KEYWORDS: Shape memory alloys, Smart materials, Chemical elements, Manufacturing, Composites, Aircraft structures, Resistance, Adhesives, Actuators, Smart structures

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Proceedings Article | 27 June 2002 Paper

Application of chirped fiber Bragg grating sensors for damage identification in composites

Nobuo Takeda, Yoji Okabe, Ryohei Tsuji, Shin-ichi Takeda

Proceedings Volume 4694, (2002) https://doi.org/10.1117/12.472608

KEYWORDS: Fiber Bragg gratings, Sensors, Reflection, Composites, Optical fibers, Refractive index, Wave propagation, Carbon, Coating, Computer simulations

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Proceedings Article | 27 June 2002 Paper

Crack identification in CFRP laminates using small-diameter FBG sensors

Tadahito Mizutani, Yoji Okabe, Nobuo Takeda

Proceedings Volume 4694, (2002) https://doi.org/10.1117/12.472638

KEYWORDS: Fiber Bragg gratings, Sensors, Optical fibers, Reflectivity, Refractive index, Inverse scattering, Finite element methods, Cladding, Carbon, Reflection

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Proceedings Article | 27 June 2002 Paper

Detection of delamination in composite laminates using small-diameter FBG sensors

Shin-ichi Takeda, Yoji Okabe, Nobuo Takeda

Proceedings Volume 4694, (2002) https://doi.org/10.1117/12.472611

KEYWORDS: Fiber Bragg gratings, Sensors, Composites, Optical fibers, Edge detection, Reflection, Interfaces, Refractive index, Carbon, X-rays

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Proceedings Article | 27 June 2002 Paper

Temperature-compensated strain measurement using FBG sensors embedded in composite laminates

Nobuhira Tanaka, Yoji Okabe, Nobuo Takeda

Proceedings Volume 4694, (2002) https://doi.org/10.1117/12.472634

KEYWORDS: Sensors, Fiber Bragg gratings, Temperature metrology, Epoxies, Optical fibers, Composites, Birefringence, Adhesives, Carbon, Glasses

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Proceedings Article | 27 June 2002 Paper

Development of multipoint strain measurement systems using small-diameter fiber Bragg gratings

Seiji Kojima, Kouji Satori, Keisuke Fukuchi, Akihito Hongo, Nobuo Takeda

Proceedings Volume 4694, (2002) https://doi.org/10.1117/12.472619

KEYWORDS: Fiber Bragg gratings, Wavelength division multiplexing, Sensors, Optical fibers, Polarization, Modulation, Fiber couplers, Composites, Light sources, Refractive index

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Proceedings Article | 18 June 2002 Paper

Effect of thermal residual stress on the reflection spectrum from FBG sensors embedded in CFRP composites

Yoji Okabe, Shigeki Yashiro, Ryohei Tsuji, Tadahito Mizutani, Nobuo Takeda

Proceedings Volume 4704, (2002) https://doi.org/10.1117/12.470709

KEYWORDS: Fiber Bragg gratings, Sensors, Thermal effects, Reflection, Temperature metrology, Optical fibers, Birefringence, Coating, Manufacturing, Composites

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Proceedings Article | 18 June 2002 Paper

Quantitative evaluation of the electrically conductive internal network in CFRP composites

Jae Park, Tomonaga Okabe, Akinori Yoshimura, Nobuo Takeda, William Curtin

Proceedings Volume 4704, (2002) https://doi.org/10.1117/12.470734

KEYWORDS: Resistance, Anisotropy, Composites, Carbon, Electrodes, Monte Carlo methods, Surface finishing, Epoxies, Polishing, Photomicroscopy

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Proceedings Article | 16 August 2001 Paper

Impact damage detection of stiffened composite panels by using embedded small-diameter optical fibers

Hiroaki Tsutsui, Akio Kawamata, Tomio Sanda, Nobuo Takeda

Proceedings Volume 4327, (2001) https://doi.org/10.1117/12.436539

KEYWORDS: Optical fibers, Composites, Skin, Sensors, Fiber Bragg gratings, Fiber optics sensors, Tissue optics, Cladding, Damage detection, Optical testing

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Proceedings Article | 6 August 2001 Paper

Polyimide-coated small-diameter optical fiber sensors for embedding in composite laminate structures

Kouji Satori, Keisuke Fukuchi, Yoshinori Kurosawa, Akihito Hongo, Nobuo Takeda

Proceedings Volume 4328, (2001) https://doi.org/10.1117/12.435531

KEYWORDS: Fiber Bragg gratings, Optical fibers, Heat treatments, Sensors, Composites, Hydrogen, Fiber reinforced polymers, Refractive index, Fiber optics sensors, Time division multiplexing

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Proceedings Article | 6 August 2001 Paper

Application of small-diameter FBG sensors for detection of damages in composites

Yoji Okabe, Tadahito Mizutani, Shigeki Yashiro, Nobuo Takeda

Proceedings Volume 4328, (2001) https://doi.org/10.1117/12.435532

KEYWORDS: Sensors, Fiber Bragg gratings, Optical fibers, Composites, Reflection, Coating, Carbon, Cladding, Refractive index, Smart materials

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Proceedings Article | 6 August 2001 Paper

Development of conductive FRP containing carbon phase for self-diagnosis structures

Yoshiki Okuhara, Soon-Gi Shin, Hideaki Matsubara, Hiroaki Yanagida, Nobuo Takeda

Proceedings Volume 4328, (2001) https://doi.org/10.1117/12.435534

KEYWORDS: Carbon, Resistance, Composites, Particles, Glasses, Fiber reinforced polymers, Dielectrics, Spherical lenses, Structured optical fibers, Reflectometry

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Proceedings Article | 6 August 2001 Paper

In-situ health monitoring of CFRP composites using electrical characteristics

Jae Park, Tomonaga Okabe, Dong Song, Nobuo Takeda, Akihiko Kitano

Proceedings Volume 4328, (2001) https://doi.org/10.1117/12.435535

KEYWORDS: Resistance, Carbon, Composites, Data modeling, Monte Carlo methods, Smart materials, Epoxies, Statistical analysis, Statistical modeling, Resistors

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Proceedings Article | 24 July 2001 Paper

Strain measurement using a Brillouin optical time domain reflectometer for development of aircraft structure health monitoring system

Takayuki Shimizu, Takashi Yari, Kanehiro Nagai, Nobuo Takeda

Proceedings Volume 4335, (2001) https://doi.org/10.1117/12.434187

KEYWORDS: Fiber Bragg gratings, Spatial resolution, Temperature metrology, Optical fibers, Wavelength division multiplexing, Reflectometry, Scattering, Aircraft structures, Aerospace engineering, Cryogenics

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Proceedings Article | 11 July 2001 Paper

Development of damage suppression system using embedded SMA foil in CFRP laminates

Toshimichi Ogisu, Masato Nomura, Norio Ando, Junji Takaki, Masakazu Kobayashi, Tomonaga Okabe, Nobuo Takeda

Proceedings Volume 4333, (2001) https://doi.org/10.1117/12.432778

KEYWORDS: Shape memory alloys, Oxides, Adhesives, Resistance, Composites, Metals, Embedded systems, Ions, Actuators, Smart materials

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Proceedings Article | 14 June 2001 Paper

Structural health monitoring methodology for aircraft condition-based maintenance

Jordi Saniger, Livier Reithler, Didier Guedra-Degeorges, Nobuo Takeda, Jean Pierre Dupuis

Proceedings Volume 4332, (2001) https://doi.org/10.1117/12.429645

KEYWORDS: Sensors, Acoustic emission, Composites, Structural health monitoring, Anisotropy, Signal attenuation, Calibration, Wave propagation, Lead, Aerospace engineering

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Proceedings Article | 14 June 2001 Paper

Structural health monitoring using FBG sensor in space environment

Shigenori Kabashima, Tsuyoshi Ozaki, Nobuo Takeda

Proceedings Volume 4332, (2001) https://doi.org/10.1117/12.429644

KEYWORDS: Fiber Bragg gratings, Sensors, Satellites, Optical fibers, Composites, Environmental sensing, Connectors, Temperature metrology, Metals, Aluminum

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Proceedings Article | 6 April 2001 Paper

Self-diagnosis function of fiber-reinforced composite with conductive particles

Yoshiki Okuhara, Soon-Gi Shin, Hideaki Matsubara, Hiroaki Yanagida, Nobuo Takeda

Proceedings Volume 4234, (2001) https://doi.org/10.1117/12.424387

KEYWORDS: Resistance, Composites, Particles, Carbon, Tin, Structured optical fibers, Fiber reinforced polymers, Tungsten, Glasses, Diagnostics

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Proceedings Article | 9 November 2000 Paper

Real-time damage detection of composite laminates with embedded Bragg grating sensors

Nobuo Takeda

Proceedings Volume 4185, 41850R (2000) https://doi.org/10.1117/12.2302170

KEYWORDS: Sensors, Fiber Bragg gratings, Reflection, Composites, Damage detection, Bragg gratings, Optical fibers, Carbon, Coating, Spectrum analysis

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Proceedings Article | 22 June 2000 Paper

Damage detection of satellite structures by optical fiber with small diameter

Shigenori Kabashima, Tsuyoshi Ozaki, Nobuo Takeda

Proceedings Volume 3985, (2000) https://doi.org/10.1117/12.388837

KEYWORDS: Optical fibers, Satellites, Reliability, Interfaces, Composites, Fiber optics sensors, Distortion, Sensors, Damage detection, Manufacturing

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