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C. V. Krishnamurthy - One of the best experts on this subject based on the ideXlab platform.

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baseline data from a healthy structure. An expression has been derived to determine the Delamination Size, from group velocities of primary Lamb modes in the sub-laminates and time-of-flight of transmitted Ao signal and mode converted Ao signal, which is generated when Ao mode propagates through a Delamination. The effectiveness of the expression, when group velocities of primary Lamb modes in the main laminate were used, has been verified through numerical simulations carried out on a quasi-isotropic glass/epoxy laminate with various Delamination interfaces. The effectiveness of the expression has also been verified experimentally, on two GFRP cross-ply laminates of [0/90/0] lay-up with 40 mm and 50 mm Delamination Sizes, using air coupled ultrasonic transducers. The predicted Delamination Sizes were found to be in go...

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baselin...

C. Ramadas - One of the best experts on this subject based on the ideXlab platform.

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baseline data from a healthy structure. An expression has been derived to determine the Delamination Size, from group velocities of primary Lamb modes in the sub-laminates and time-of-flight of transmitted Ao signal and mode converted Ao signal, which is generated when Ao mode propagates through a Delamination. The effectiveness of the expression, when group velocities of primary Lamb modes in the main laminate were used, has been verified through numerical simulations carried out on a quasi-isotropic glass/epoxy laminate with various Delamination interfaces. The effectiveness of the expression has also been verified experimentally, on two GFRP cross-ply laminates of [0/90/0] lay-up with 40 mm and 50 mm Delamination Sizes, using air coupled ultrasonic transducers. The predicted Delamination Sizes were found to be in go...

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baselin...

Shinichi Takeda - One of the best experts on this subject based on the ideXlab platform.

  • monitoring of Delamination growth in cfrp laminates using chirped fbg sensors
    Journal of Intelligent Material Systems and Structures, 2008
    Co-Authors: Shinichi Takeda, Yoji Okabe, Nobuo Takeda
    Abstract:

    Chirped fiber Bragg grating (FBG) sensors are applied to the monitoring of the propagation direction and the Size of a Delamination in CFRP cross-ply laminates, since it has been found previously that the reflection spectrum from chirped FBG sensors is expressed as a function of their positions along the grating. The reflection spectra are measured at various Delamination lengths under a four-point bending test. Two chirped FBG sensors are embedded in two opposite directions in order to investigate the relationship between the deformation of the spectrum and the propagation direction of the Delamination. The spectrum changes sensitively depending on both the Size and the propagation direction of the Delamination. For confirmation of the measured results, the spectra are simulated using FEA computed strain distributions of the chirped FBG sensors. In the simulation, a birefringence effect of the optical fiber on the spectrum is observed in the case of chirped FBG sensors. The relationship between the measured spectral change and the Delamination growth is illustrated by the calculated spectra, the strain distributions, and the properties of the chirped FBG sensors. As a result, it is found that not only the Delamination Size, but also the propagation direction of the Delamination can be evaluated by using chirped FBG sensors.

  • Delamination monitoring of laminated composites subjected to low velocity impact using small diameter fbg sensors
    Composites Part A-applied Science and Manufacturing, 2005
    Co-Authors: Shu Minakuchi, Shinichi Takeda, Yoji Okabe
    Abstract:

    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.

Janardhan M Padiyar - One of the best experts on this subject based on the ideXlab platform.

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baseline data from a healthy structure. An expression has been derived to determine the Delamination Size, from group velocities of primary Lamb modes in the sub-laminates and time-of-flight of transmitted Ao signal and mode converted Ao signal, which is generated when Ao mode propagates through a Delamination. The effectiveness of the expression, when group velocities of primary Lamb modes in the main laminate were used, has been verified through numerical simulations carried out on a quasi-isotropic glass/epoxy laminate with various Delamination interfaces. The effectiveness of the expression has also been verified experimentally, on two GFRP cross-ply laminates of [0/90/0] lay-up with 40 mm and 50 mm Delamination Sizes, using air coupled ultrasonic transducers. The predicted Delamination Sizes were found to be in go...

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baselin...

Krishnan Balasubramaniam - One of the best experts on this subject based on the ideXlab platform.

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baseline data from a healthy structure. An expression has been derived to determine the Delamination Size, from group velocities of primary Lamb modes in the sub-laminates and time-of-flight of transmitted Ao signal and mode converted Ao signal, which is generated when Ao mode propagates through a Delamination. The effectiveness of the expression, when group velocities of primary Lamb modes in the main laminate were used, has been verified through numerical simulations carried out on a quasi-isotropic glass/epoxy laminate with various Delamination interfaces. The effectiveness of the expression has also been verified experimentally, on two GFRP cross-ply laminates of [0/90/0] lay-up with 40 mm and 50 mm Delamination Sizes, using air coupled ultrasonic transducers. The predicted Delamination Sizes were found to be in go...

  • Delamination Size detection using time of flight of anti symmetric ao and mode converted ao mode of guided lamb waves
    Journal of Intelligent Material Systems and Structures, 2010
    Co-Authors: C. Ramadas, Krishnan Balasubramaniam, Makarand Joshi, Janardhan M Padiyar, C. V. Krishnamurthy
    Abstract:

    In this article an attempt has been made to quantitatively assess the extent of Delamination in composite laminates, using time-of-flight of fundamental Lamb wave modes, without recourse to baselin...