The Experts below are selected from a list of 360 Experts worldwide ranked by ideXlab platform
Nobuo Takeda - One of the best experts on this subject based on the ideXlab platform.
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delamination monitoring of laminated composites subjected to low velocity impact using small diameter fbg sensors
Composites Part A-applied Science and Manufacturing, 2005Co-Authors: Yoji Okabe, Shu Minakuchi, Shinichi Takeda, Nobuo TakedaAbstract:Small-diameter fiber Bragg grating (FBG) sensors were applied for the monitoring of delamination induced by low-velocity impact. The FBG sensors were embedded into carbon fiber reinforced plastic (CFRP) laminates [04/904/04]. Using a drop-weight impact tester, an impact loading was applied to the laminates at four impact energy levels. After the impact tests, the internal damages including delaminations were observed by ultrasonic C-scan, and the reflection spectra from the embedded FBG sensors were Measured. The form of the Spectrum changed sensitively depending on the delamination size. Furthermore, the spectra were calculated theoretically for confirmation of the Measured spectra. Since the change in the Measured Spectrum was consistent with that in the calculated Spectrum, the relationship between the delamination size and the form of the Spectrum could be clarified. From the results, the present method using small-diameter FBG sensors was found to be effective for the monitoring of the delamination.
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application of chirped fbg sensors for detection of local delamination in composite laminates
Smart Structures and Materials 2003: Smart Sensor Technology and Measurement Systems, 2003Co-Authors: Shinichi Takeda, Yoji Okabe, Nobuo TakedaAbstract:Chirped fiber Bragg (FBG) sensors were applied for the detection of delamination in carbon fiber reinforced plastics (CFRP) cross-ply laminates. Reflection spectra from the embedded chirped FBG sensor were Measured at various delamination lengths under static four-point bending test. The sensor were embedded into two different positions for the investigation of the relation between the Spectrum and the direction of delamination propagation. The Spectrum changed sensitively depending on both the delamination length and the direction of the delamination propagation. For confirmation of the Measured results, the Spectrum was simulated considering the strain distribution in the chirped FBG sensor theoretically. The change in the form of the Measured Spectrum was consistent with that of the calculated Spectrum. Moreover, the area ratio of the two peaks in the Spectrum and the Spectrum width were proposed as effective indicators for the identification of the local delamination.
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delamination detection in cfrp laminates with embedded small diameter fiber bragg grating sensors
Composites Part A-applied Science and Manufacturing, 2002Co-Authors: Shinichi Takeda, Yoji Okabe, Nobuo TakedaAbstract:Newly developed small-diameter fiber Bragg grating (FBG) sensors were applied for the detection of the delamination in carbon fiber reinforced plastic (CFRP) cross-ply laminates. Since the diameter of the FBG sensor was very small, the sensor was easily embedded into the 0° ply along the reinforcing carbon fibers. The reflection spectra from the FBG sensor were Measured at various delamination lengths through four-point bending test. The form of the Spectrum changed sensitively, as the delamination length increased. Moreover, the Spectrum was calculated theoretically for confirmation of the Measured Spectrum. The calculated result reproduced the change in the Measured Spectrum very well. Then, we proposed the intensity ratio in the Spectrum as an effective indicator for the prediction of the delamination length. This indicator has a potential to be applied to other laminate configurations.
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detection of transverse cracks in cfrp composites using embedded fiber bragg grating sensors
Smart Materials and Structures, 2000Co-Authors: Yoji Okabe, Tatsuro Kosaka, Shigeki Yashiro, Nobuo TakedaAbstract:In the present research, fiber Bragg grating (FBG) sensors were applied for the detection of transverse cracks, which cause strain distribution within the gage length, in carbon fiber reinforced plastic (CFRP) cross-ply laminates. An uncoated FBG sensor was embedded in 0° ply on the border of 90° ply in a CFRP cross-ply laminate. The reflection spectra from the FBG sensor were Measured at various tensile stresses. As a result, the reflection Spectrum became broad and had some peaks with an increase of the transverse crack density in the 90° ply. After the crack density was saturated, the Spectrum became narrow and had one large peak again. In order to confirm that the change in the Spectrum was caused by transverse cracks, the spectra were calculated theoretically. The calculated result reproduced the change in the Measured Spectrum very well. These results show that the occurrence of transverse cracks can be detected from the change in the form of the reflection Spectrum, and that the Spectrum width at the half maximum is a good indicator for the quantitative evaluation of the transverse crack density in real time.
Hansdieter Meyer - One of the best experts on this subject based on the ideXlab platform.
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full dimensional 15 dimensional quantum dynamical simulation of the protonated water dimer ii infrared Spectrum and vibrational dynamics
Journal of Chemical Physics, 2007Co-Authors: Oriol Vendrell, Fabien Gatti, Hansdieter MeyerAbstract:The infrared absorption Spectrum of the protonated water dimer (H5O2+) is simulated in full dimensionality (15 dimensional) in the spectral range of 0-4000 cm(-1). The calculations are performed using the multiconfiguration time-dependent Hartree (MCTDH) method for propagation of wavepackets. All the fundamentals and several overtones of the vibrational motion are computed. The Spectrum of H5O2+ is shaped to a large extent by couplings of the proton-transfer motion to large amplitude fluxional motions of the water molecules, water bending and water-water stretch motions. These couplings are identified and discussed, and the corresponding spectral lines are assigned. The large couplings featured by H5O2+ do not hinder, however, to describe the coupled vibrational motion by well defined simple types of vibration (stretching, bending; etc.) based on well defined modes of vibration, in terms of which the spectral lines are assigned. Comparison of our results to recent experiments and calculations on the system is given. The reported MCTDH IR Spectrum is in very good agreement to the recently Measured Spectrum by Hammer et al. [J. Chem. Phys. 122, 244301 (2005)].
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full dimensional 15d quantum dynamical simulation of the protonated water dimer ii infrared Spectrum and vibrational dynamics
arXiv: Chemical Physics, 2007Co-Authors: Oriol Vendrell, Fabien Gatti, Hansdieter MeyerAbstract:The infrared absorption Spectrum of the protonated water dimer (H5O2+) is simulated in full dimensionality (15D) in the spectral range 0-4000 cm-1. The calculations are performed using the Multiconfiguration Time-Dependent Hartree (MCTDH) method for propagation of wavepackets. All the fundamentals and several overtones of the vibrational motion are computed. The Spectrum of H5O2+ is shaped to a large extent by couplings of the proton-transfer motion to large amplitude fluxional motions of the water molecules, water bending and water-water stretch motions. These couplings are identified and discussed, and the corresponding spectral lines assigned. The large couplings featured by H5O2+ do not hinder, however, to describe the coupled vibrational motion by well defined simple types of vibration (stretching, bending, etc.) based on well defined modes of vibration, in terms of which the spectral lines are assigned. Comparison of our results to recent experiments and calculations on the system is given. The reported MCTDH IR-Spectrum is in very good agreement to the recently Measured Spectrum by Hammer et al. [JCP, 122, 244301, (2005)].
Daniel M Neumark - One of the best experts on this subject based on the ideXlab platform.
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high resolution photoelectron spectroscopy of tio3h2 probing the tio2 h2o dissociative adduct
Journal of Chemical Physics, 2018Co-Authors: Jessalyn A Devine, Ali Abou Taka, Mark C Babin, Marissa L Weichman, Hrant P Hratchian, Daniel M NeumarkAbstract:Slow electron velocity-map imaging spectroscopy of cryogenically cooled TiO3H2− anions is used to probe the simplest titania/water reaction, TiO20/− + H2O. The resultant spectra show vibrationally resolved structure assigned to detachment from the cis-dihydroxide TiO(OH)2− geometry based on density functional theory calculations, demonstrating that for the reaction of the anionic TiO2− monomer with a single water molecule, the dissociative adduct (where the water is split) is energetically preferred over a molecularly adsorbed geometry. This work represents a significant improvement in resolution over previous measurements, yielding an electron affinity of 1.2529(4) eV as well as several vibrational frequencies for neutral TiO(OH)2. The energy resolution of the current results combined with photoelectron angular distributions reveals Herzberg-Teller coupling-induced transitions to Franck-Condon forbidden vibrational levels of the neutral ground state. A comparison to the previously Measured Spectrum of ba...
Shinichi Takeda - One of the best experts on this subject based on the ideXlab platform.
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delamination monitoring of laminated composites subjected to low velocity impact using small diameter fbg sensors
Composites Part A-applied Science and Manufacturing, 2005Co-Authors: Yoji Okabe, Shu Minakuchi, Shinichi Takeda, Nobuo TakedaAbstract:Small-diameter fiber Bragg grating (FBG) sensors were applied for the monitoring of delamination induced by low-velocity impact. The FBG sensors were embedded into carbon fiber reinforced plastic (CFRP) laminates [04/904/04]. Using a drop-weight impact tester, an impact loading was applied to the laminates at four impact energy levels. After the impact tests, the internal damages including delaminations were observed by ultrasonic C-scan, and the reflection spectra from the embedded FBG sensors were Measured. The form of the Spectrum changed sensitively depending on the delamination size. Furthermore, the spectra were calculated theoretically for confirmation of the Measured spectra. Since the change in the Measured Spectrum was consistent with that in the calculated Spectrum, the relationship between the delamination size and the form of the Spectrum could be clarified. From the results, the present method using small-diameter FBG sensors was found to be effective for the monitoring of the delamination.
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application of chirped fbg sensors for detection of local delamination in composite laminates
Smart Structures and Materials 2003: Smart Sensor Technology and Measurement Systems, 2003Co-Authors: Shinichi Takeda, Yoji Okabe, Nobuo TakedaAbstract:Chirped fiber Bragg (FBG) sensors were applied for the detection of delamination in carbon fiber reinforced plastics (CFRP) cross-ply laminates. Reflection spectra from the embedded chirped FBG sensor were Measured at various delamination lengths under static four-point bending test. The sensor were embedded into two different positions for the investigation of the relation between the Spectrum and the direction of delamination propagation. The Spectrum changed sensitively depending on both the delamination length and the direction of the delamination propagation. For confirmation of the Measured results, the Spectrum was simulated considering the strain distribution in the chirped FBG sensor theoretically. The change in the form of the Measured Spectrum was consistent with that of the calculated Spectrum. Moreover, the area ratio of the two peaks in the Spectrum and the Spectrum width were proposed as effective indicators for the identification of the local delamination.
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delamination detection in cfrp laminates with embedded small diameter fiber bragg grating sensors
Composites Part A-applied Science and Manufacturing, 2002Co-Authors: Shinichi Takeda, Yoji Okabe, Nobuo TakedaAbstract:Newly developed small-diameter fiber Bragg grating (FBG) sensors were applied for the detection of the delamination in carbon fiber reinforced plastic (CFRP) cross-ply laminates. Since the diameter of the FBG sensor was very small, the sensor was easily embedded into the 0° ply along the reinforcing carbon fibers. The reflection spectra from the FBG sensor were Measured at various delamination lengths through four-point bending test. The form of the Spectrum changed sensitively, as the delamination length increased. Moreover, the Spectrum was calculated theoretically for confirmation of the Measured Spectrum. The calculated result reproduced the change in the Measured Spectrum very well. Then, we proposed the intensity ratio in the Spectrum as an effective indicator for the prediction of the delamination length. This indicator has a potential to be applied to other laminate configurations.
Oriol Vendrell - One of the best experts on this subject based on the ideXlab platform.
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full dimensional 15 dimensional quantum dynamical simulation of the protonated water dimer ii infrared Spectrum and vibrational dynamics
Journal of Chemical Physics, 2007Co-Authors: Oriol Vendrell, Fabien Gatti, Hansdieter MeyerAbstract:The infrared absorption Spectrum of the protonated water dimer (H5O2+) is simulated in full dimensionality (15 dimensional) in the spectral range of 0-4000 cm(-1). The calculations are performed using the multiconfiguration time-dependent Hartree (MCTDH) method for propagation of wavepackets. All the fundamentals and several overtones of the vibrational motion are computed. The Spectrum of H5O2+ is shaped to a large extent by couplings of the proton-transfer motion to large amplitude fluxional motions of the water molecules, water bending and water-water stretch motions. These couplings are identified and discussed, and the corresponding spectral lines are assigned. The large couplings featured by H5O2+ do not hinder, however, to describe the coupled vibrational motion by well defined simple types of vibration (stretching, bending; etc.) based on well defined modes of vibration, in terms of which the spectral lines are assigned. Comparison of our results to recent experiments and calculations on the system is given. The reported MCTDH IR Spectrum is in very good agreement to the recently Measured Spectrum by Hammer et al. [J. Chem. Phys. 122, 244301 (2005)].
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full dimensional 15d quantum dynamical simulation of the protonated water dimer ii infrared Spectrum and vibrational dynamics
arXiv: Chemical Physics, 2007Co-Authors: Oriol Vendrell, Fabien Gatti, Hansdieter MeyerAbstract:The infrared absorption Spectrum of the protonated water dimer (H5O2+) is simulated in full dimensionality (15D) in the spectral range 0-4000 cm-1. The calculations are performed using the Multiconfiguration Time-Dependent Hartree (MCTDH) method for propagation of wavepackets. All the fundamentals and several overtones of the vibrational motion are computed. The Spectrum of H5O2+ is shaped to a large extent by couplings of the proton-transfer motion to large amplitude fluxional motions of the water molecules, water bending and water-water stretch motions. These couplings are identified and discussed, and the corresponding spectral lines assigned. The large couplings featured by H5O2+ do not hinder, however, to describe the coupled vibrational motion by well defined simple types of vibration (stretching, bending, etc.) based on well defined modes of vibration, in terms of which the spectral lines are assigned. Comparison of our results to recent experiments and calculations on the system is given. The reported MCTDH IR-Spectrum is in very good agreement to the recently Measured Spectrum by Hammer et al. [JCP, 122, 244301, (2005)].