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Acoustic Emission Testing

The Experts below are selected from a list of 306 Experts worldwide ranked by ideXlab platform

Cássie G. Lopes – 1st expert on this subject based on the ideXlab platform

  • EUSIPCO – Modeling Time of Arrival Probability Distribution and TDOA Bias in Acoustic Emission Testing
    2018 26th European Signal Processing Conference (EUSIPCO), 2018
    Co-Authors: Carlos A. Prete Junior, Vítor H. Nascimento, Cássie G. Lopes

    Abstract:

    Acoustic Emission Testing is widely used by industry to detect and localize faults in structures, but estimated source positions often show significant bias in real tests as a consequence of Time Difference of Arrival (TDOA) bias. In this work, a model for TDOA bias is developed considering the time of arrival was estimated using the fixed threshold algorithm, as well as theoretical upper and lower bounds for it. In addition, we derive the time of arrival probability distribution function in terms of the noise distribution and Acoustic Emission waveform for the fixed threshold algorithm, showing that, contrary to usual practice, it in general cannot be well approximated by a Gaussian distribution.

  • Modeling Time of Arrival Probability Distribution and TDOA Bias in Acoustic Emission Testing
    2018 26th European Signal Processing Conference (EUSIPCO), 2018
    Co-Authors: Carlos A. Prete, Vítor H. Nascimento, Cássie G. Lopes

    Abstract:

    Acoustic Emission Testing is widely used by industry to detect and localize faults in structures, but estimated source positions often show significant bias in real tests as a consequence of Time Difference of Arrival (TDOA) bias. In this work, a model for TDOA bias is developed considering the time of arrival was estimated using the fixed threshold algorithm, as well as theoretical upper and lower bounds for it. In addition, we derive the time of arrival probability distribution function in terms of the noise distribution and Acoustic Emission waveform for the fixed threshold algorithm, showing that, contrary to usual practice, it in general cannot be well approximated by a Gaussian distribution.

Daniel J. Inman – 2nd expert on this subject based on the ideXlab platform

  • Piezoelectric Zinc Oxide Nanowires for Use in Acoustic Emission Testing
    , 2018
    Co-Authors: Lorianne Groo, Henry Angelo Sodano, Daniel J. Inman

    Abstract:

    © 2017 by DEStech Publications, Inc. Acoustic Emission Testing has proven useful for real-time damage detection in a variety of situations, however the need for externally bonded sensors limits the feasible applications. This work investigates an alternative approach to traditional Acoustic Emission Testing by using piezoelectric zinc oxide (ZnO) nanowires fully integrated into fiber-reinforced polymer composites. The ZnO nanowires are conformally grown on the surface of woven aramid fabrics via a hydrothermal growth process after which the fabric with ZnO nanowires is placed between layers of woven carbon fiber using vacuum assisted resin transfer molding forming multilayer composites. While the nanowires serve as embedded sensors in the samples, the carbon fiber layer serve as electrodes across which the voltage of the composite can be measured. The composite samples are subjected to a standard tensile test during which the sample voltage output is measured using wire leads attached to the carbon fiber electrodes. Damage to the composite sample during Testing results in elastic waves which are converted to measurable electric field by the piezoelectric nanowires. The recorded sample voltage is used to detect instances of internal damage by evaluating the amplitude and number of Acoustic Emission hits during mechanical Testing up to the point of failure. The measured voltage is used to detect internal damage to the composite at less than 50% of the maximum strain thus demonstrating the use of ZnO nanowires in real-time damage detection.

  • piezoelectric zinc oxide nanowires for use in Acoustic Emission Testing
    Proceedings of the American Society for Composites — Thirty-second Technical Conference, 2017
    Co-Authors: Lorianne Groo, Henry Angelo Sodano, Daniel J. Inman

    Abstract:

    Acoustic Emission Testing has proven useful for real-time damage detection in a variety of situations, however the need for externally bonded sensors limits the feasible applications. This work investigates an alternative approach to traditional Acoustic Emission Testing by using piezoelectric zinc oxide (ZnO) nanowires fully integrated into fiber-reinforced polymer composites. The ZnO nanowires are conformally grown on the surface of woven aramid fabrics via a hydrothermal growth process after which the fabric with ZnO nanowires is placed between layers of woven carbon fiber using vacuum assisted resin transfer molding forming multilayer composites. While the nanowires serve as embedded sensors in the samples, the carbon fiber layer serve as electrodes across which the voltage of the composite can be measured. The composite samples are subjected to a standard tensile test during which the sample voltage output is measured using wire leads attached to the carbon fiber electrodes. Damage to the composite sample during Testing results in elastic waves which are converted to measurable electric field by the piezoelectric nanowires. The recorded sample voltage is used to detect instances of internal damage by evaluating the amplitude and number of Acoustic Emission hits during mechanical Testing up to the point of failure. The measured voltage is used to detect internal damage to the composite at less than 50% of the maximum strain thus demonstrating the use of ZnO nanowires in real-time damage detection.

Carlos A. Prete – 3rd expert on this subject based on the ideXlab platform

  • Modeling Time of Arrival Probability Distribution and TDOA Bias in Acoustic Emission Testing
    2018 26th European Signal Processing Conference (EUSIPCO), 2018
    Co-Authors: Carlos A. Prete, Vítor H. Nascimento, Cássie G. Lopes

    Abstract:

    Acoustic Emission Testing is widely used by industry to detect and localize faults in structures, but estimated source positions often show significant bias in real tests as a consequence of Time Difference of Arrival (TDOA) bias. In this work, a model for TDOA bias is developed considering the time of arrival was estimated using the fixed threshold algorithm, as well as theoretical upper and lower bounds for it. In addition, we derive the time of arrival probability distribution function in terms of the noise distribution and Acoustic Emission waveform for the fixed threshold algorithm, showing that, contrary to usual practice, it in general cannot be well approximated by a Gaussian distribution.