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Laurence J. Jacobs - One of the best experts on this subject based on the ideXlab platform.

  • determination of absolute Material Nonlinearity with air coupled ultrasonic receivers
    Ultrasonics, 2017
    Co-Authors: David Torello, Jianmin Qu, Nicholas Selby, Laurence J. Jacobs
    Abstract:

    Abstract Quantitative evaluation of the microstructural state of a specimen can be deduced from knowledge of the sample’s absolute acoustic Nonlinearity parameter, β , making the measurement of β a powerful tool in the NDE toolbox. However, the various methods used in the past to measure β each suffer from significant limitations. Piezoelectric contact transducers are sensitive to nonlinear signals, cheap, and simple to use, but they are hindered by the variability of the interfacial contact between transducer and specimen surface. Laser interferometry provides non-contact detection, but requires carefully prepared specimens or complicated optics to maximize sensitivity to the higher harmonic components of a received waveform. Additionally, laser interferometry is expensive and relatively difficult to use in the field. Air-coupled piezoelectric transducers offer the strengths of both of these technologies and the weaknesses of neither, but are notoriously difficult to calibrate for use in nonlinear measurements. This work proposes a hybrid modeling and experimental approach to air-coupled transducer calibration and the use of this calibration in a model-based optimization to determine the absolute β parameter of the Material under investigation. This approach is applied to aluminum and fused silica, which are both well-documented Materials and provide a strong reference for comparison of experimental and modeling results.

  • measurement and fitting techniques for the assessment of Material Nonlinearity using nonlinear rayleigh waves
    41ST ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 34, 2015
    Co-Authors: David Torello, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This research considers the effects of diffraction, attenuation, and the Nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the Nonlinearity parameter β11 is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the Nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β117075/β112024 measure of 1.363 agrees well with previous literature and earlier work.This research considers the effects of diffraction, attenuation, and the Nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the Nonlinearity parameter β11 is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the Nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β117075/β112024 measure of 1.363 agrees well with previous literature and earlier work.

  • air coupled detection of nonlinear rayleigh surface waves to assess Material Nonlinearity
    Ultrasonics, 2014
    Co-Authors: Sebastian Thiele, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This research presents a new technique for nonlinear Rayleigh surface wave measurements that uses a non-contact, air-coupled ultrasonic transducer; this receiver is less dependent on surface conditions than laser-based detection, and is much more accurate and efficient than detection with a contact wedge transducer. A viable experimental setup is presented that enables the robust, non-contact measurement of nonlinear Rayleigh surface waves over a range of propagation distances. The relative Nonlinearity parameter is obtained as the slope of the normalized second harmonic amplitudes plotted versus propagation distance. This experimental setup is then used to assess the relative Nonlinearity parameters of two aluminum alloy specimens (Al 2024-T351 and Al 7075-T651). These results demonstrate the effectiveness of the proposed technique – the average standard deviation of the normalized second harmonic amplitudes, measured at locations along the propagation path, is below 2%. Experimental validation is provided by a comparison of the ratio of the measured Nonlinearity parameters of these specimens with ratios from the absolute Nonlinearity parameters for the same Materials measured by capacitive detection of nonlinear longitudinal waves.

  • nonlinear lamb waves for the detection of Material Nonlinearity
    Mechanical Systems and Signal Processing, 2008
    Co-Authors: Christian Bermes, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This paper reports on a method that uses nonlinear Lamb waves to detect Material Nonlinearity. Lamb waves are well suited for the interrogation of thin metallic layers which act as waveguides, giving Lamb waves great potential in nondestructive evaluation applications. However, measuring nonlinear Lamb waves and extracting the information necessary for nondestructive evaluation is complicated by the inherent dispersive and multi-mode nature of Lamb waves. This paper presents a procedure that overcomes these difficulties and develops a reliable and robust measurement methodology. By using hybrid wedge generation and laser interferometric detection in combination with signal processing in the time–frequency domain, it is possible to make relative measurements of Material Nonlinearity parameters, which are an indicator of plasticity-driven damage.

  • A new technique for measuring the acoustic Nonlinearity of Materials using Rayleigh waves
    NDT and E International, 2008
    Co-Authors: Guoshuang Shui, Jin-yeon Kim, Yue-sheng Wang, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This note presents a procedure to generate nonlinear Rayleigh surface waves without having to drive the transmitting piezoelectric transducer at high voltages; driving at low voltages limits the excitation of the intrinsic Nonlinearity of the piezoelectric transducer element, and enables an efficient measurement procedure to isolate inherent Material Nonlinearity. The capabilities of this proposed technique are demonstrated by measuring the Material Nonlinearity of aluminum alloy 2024 and 6061 plates with Rayleigh surface waves. © 2008 Elsevier Ltd. All rights reserved.

Jianmin Qu - One of the best experts on this subject based on the ideXlab platform.

  • determination of absolute Material Nonlinearity with air coupled ultrasonic receivers
    Ultrasonics, 2017
    Co-Authors: David Torello, Jianmin Qu, Nicholas Selby, Laurence J. Jacobs
    Abstract:

    Abstract Quantitative evaluation of the microstructural state of a specimen can be deduced from knowledge of the sample’s absolute acoustic Nonlinearity parameter, β , making the measurement of β a powerful tool in the NDE toolbox. However, the various methods used in the past to measure β each suffer from significant limitations. Piezoelectric contact transducers are sensitive to nonlinear signals, cheap, and simple to use, but they are hindered by the variability of the interfacial contact between transducer and specimen surface. Laser interferometry provides non-contact detection, but requires carefully prepared specimens or complicated optics to maximize sensitivity to the higher harmonic components of a received waveform. Additionally, laser interferometry is expensive and relatively difficult to use in the field. Air-coupled piezoelectric transducers offer the strengths of both of these technologies and the weaknesses of neither, but are notoriously difficult to calibrate for use in nonlinear measurements. This work proposes a hybrid modeling and experimental approach to air-coupled transducer calibration and the use of this calibration in a model-based optimization to determine the absolute β parameter of the Material under investigation. This approach is applied to aluminum and fused silica, which are both well-documented Materials and provide a strong reference for comparison of experimental and modeling results.

  • measurement and fitting techniques for the assessment of Material Nonlinearity using nonlinear rayleigh waves
    41ST ANNUAL REVIEW OF PROGRESS IN QUANTITATIVE NONDESTRUCTIVE EVALUATION: Volume 34, 2015
    Co-Authors: David Torello, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This research considers the effects of diffraction, attenuation, and the Nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the Nonlinearity parameter β11 is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the Nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β117075/β112024 measure of 1.363 agrees well with previous literature and earlier work.This research considers the effects of diffraction, attenuation, and the Nonlinearity of generating sources on measurements of nonlinear ultrasonic Rayleigh wave propagation. A new theoretical framework for correcting measurements made with air-coupled and contact piezoelectric receivers for the aforementioned effects is provided based on analytical models and experimental considerations. A method for extracting the Nonlinearity parameter β11 is proposed based on a nonlinear least squares curve-fitting algorithm that is tailored for Rayleigh wave measurements. Quantitative experiments are conducted to confirm the predictions for the Nonlinearity of the piezoelectric source and to demonstrate the effectiveness of the curve-fitting procedure. These experiments are conducted on aluminum 2024 and 7075 specimens and a β117075/β112024 measure of 1.363 agrees well with previous literature and earlier work.

  • air coupled detection of nonlinear rayleigh surface waves to assess Material Nonlinearity
    Ultrasonics, 2014
    Co-Authors: Sebastian Thiele, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This research presents a new technique for nonlinear Rayleigh surface wave measurements that uses a non-contact, air-coupled ultrasonic transducer; this receiver is less dependent on surface conditions than laser-based detection, and is much more accurate and efficient than detection with a contact wedge transducer. A viable experimental setup is presented that enables the robust, non-contact measurement of nonlinear Rayleigh surface waves over a range of propagation distances. The relative Nonlinearity parameter is obtained as the slope of the normalized second harmonic amplitudes plotted versus propagation distance. This experimental setup is then used to assess the relative Nonlinearity parameters of two aluminum alloy specimens (Al 2024-T351 and Al 7075-T651). These results demonstrate the effectiveness of the proposed technique – the average standard deviation of the normalized second harmonic amplitudes, measured at locations along the propagation path, is below 2%. Experimental validation is provided by a comparison of the ratio of the measured Nonlinearity parameters of these specimens with ratios from the absolute Nonlinearity parameters for the same Materials measured by capacitive detection of nonlinear longitudinal waves.

  • nonlinear lamb waves for the detection of Material Nonlinearity
    Mechanical Systems and Signal Processing, 2008
    Co-Authors: Christian Bermes, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This paper reports on a method that uses nonlinear Lamb waves to detect Material Nonlinearity. Lamb waves are well suited for the interrogation of thin metallic layers which act as waveguides, giving Lamb waves great potential in nondestructive evaluation applications. However, measuring nonlinear Lamb waves and extracting the information necessary for nondestructive evaluation is complicated by the inherent dispersive and multi-mode nature of Lamb waves. This paper presents a procedure that overcomes these difficulties and develops a reliable and robust measurement methodology. By using hybrid wedge generation and laser interferometric detection in combination with signal processing in the time–frequency domain, it is possible to make relative measurements of Material Nonlinearity parameters, which are an indicator of plasticity-driven damage.

  • A new technique for measuring the acoustic Nonlinearity of Materials using Rayleigh waves
    NDT and E International, 2008
    Co-Authors: Guoshuang Shui, Jin-yeon Kim, Yue-sheng Wang, Jianmin Qu, Laurence J. Jacobs
    Abstract:

    This note presents a procedure to generate nonlinear Rayleigh surface waves without having to drive the transmitting piezoelectric transducer at high voltages; driving at low voltages limits the excitation of the intrinsic Nonlinearity of the piezoelectric transducer element, and enables an efficient measurement procedure to isolate inherent Material Nonlinearity. The capabilities of this proposed technique are demonstrated by measuring the Material Nonlinearity of aluminum alloy 2024 and 6061 plates with Rayleigh surface waves. © 2008 Elsevier Ltd. All rights reserved.

Yanzheng Wang - One of the best experts on this subject based on the ideXlab platform.

  • reflection of ultrasound from a region of cubic Material Nonlinearity due to harmonic generation
    Acta Mechanica, 2018
    Co-Authors: Yanzheng Wang, Jan Drewes Achenbach
    Abstract:

    Two models are proposed to obtain information on the Material Nonlinearity of an inclusion in a solid body. Material Nonlinearity is usually generated by the development of Material microscale damage. When the region of nonlinear Material is large, incidence of ultrasound on the interface between the perfectly joined regions of linear and nonlinear Material behavior produces very useful information. Using the continuity condition of stress and displacement at the interface, the harmonics in the nonlinear region, together with the compensatory waves, yield a reflected wave whose amplitude contains the defining constant of the Material Nonlinearity near the interface. The compensatory waves are introduced to ensure the continuity conditions at the interface. When the nonlinear region is an inclusion, the equivalent body force induced by the Material Nonlinearity generates a backscattered wave. The backscattered wave is determined in a simple manner by the use of the reciprocity theorem of elastodynamics. The backscattered wave obtained in this manner yields information on the nonlinear Material properties and the size of the inclusion. In addition, a model based on the superposition of back-propagated compensatory waves from the two interfaces of the nonlinear region reveals the physical mechanism of wave scattering from the nonlinear inclusion.

  • analysis of harmonics propagating in pipes of quadratic Material Nonlinearity using shell theory
    International Journal of Solids and Structures, 2017
    Co-Authors: Yanzheng Wang, Weiqiu Chen, Jan Drewes Achenbach
    Abstract:

    Abstract Higher harmonics in pipes of quadratic nonlinear Material behavior have been analyzed in this paper. Using shell theory, the mixing of axisymmetric longitudinal waves and torsional waves, and the self-interaction of axisymmetric longitudinal waves, have been investigated. The dispersion curves of longitudinal waves derived from the linear version of the governing equations show excellent agreement with the corresponding curves obtained from thick shell theory and three dimensional theory, presented elsewhere. For torsional waves, only the lowest mode is taken into consideration. Using the perturbation method, analytical expressions for the resonant torsional waves generated by the mixing of longitudinal and torsional waves have been obtained. The resonant waves with difference frequencies propagate in the opposite direction of the corresponding primary wave. The back-propagation effect has potential application for nondestructive evaluation. The nonlinear shell theory is further simplified for applicability to thin pipes, to obtain expressions for the cumulative second longitudinal harmonics generated by self-interaction of longitudinal waves. For this case, the phase-match conditions, which are used to determine phase-match points, are also presented in analytical form.

  • the effect of cubic Material Nonlinearity on the propagation of torsional wave modes in a pipe
    Journal of the Acoustical Society of America, 2016
    Co-Authors: Yanzheng Wang, Jan Drewes Achenbach
    Abstract:

    The effect of cubic Material Nonlinearity on the propagation in a pipe of the lowest axially symmetric torsional wave mode has been investigated in this paper. Two cases, one that the Material of the whole pipe is nonlinear, and the second that a small segment of the pipe is nonlinear, have been considered. For the first case, a first and a third harmonic have been obtained by the perturbation method. Analytical expressions for the two cumulative harmonics have been derived. The second case leads to a scattering problem. The segment produces nonlinear terms in the equation of motion, which can be regarded as a distribution of body forces. The problem is then reduced to a linear scattering problem. An analytical expression for the backscattered wave can be easily obtained by using the elastodynamic reciprocity theorem. Due to the low amplitude of the backscattered wave, the authors propose to add another higher frequency wave to the primary wave, to increase the total magnitude of the scattered wave. An example that the originally scattered wave is amplified 50 times by selecting proper frequencies is presented. Both cases considered here have a potential application to determine the Material properties in a region of nonlinear Material behavior.The effect of cubic Material Nonlinearity on the propagation in a pipe of the lowest axially symmetric torsional wave mode has been investigated in this paper. Two cases, one that the Material of the whole pipe is nonlinear, and the second that a small segment of the pipe is nonlinear, have been considered. For the first case, a first and a third harmonic have been obtained by the perturbation method. Analytical expressions for the two cumulative harmonics have been derived. The second case leads to a scattering problem. The segment produces nonlinear terms in the equation of motion, which can be regarded as a distribution of body forces. The problem is then reduced to a linear scattering problem. An analytical expression for the backscattered wave can be easily obtained by using the elastodynamic reciprocity theorem. Due to the low amplitude of the backscattered wave, the authors propose to add another higher frequency wave to the primary wave, to increase the total magnitude of the scattered wave. An ex...

Jan Drewes Achenbach - One of the best experts on this subject based on the ideXlab platform.

  • reflection of ultrasound from a region of cubic Material Nonlinearity due to harmonic generation
    Acta Mechanica, 2018
    Co-Authors: Yanzheng Wang, Jan Drewes Achenbach
    Abstract:

    Two models are proposed to obtain information on the Material Nonlinearity of an inclusion in a solid body. Material Nonlinearity is usually generated by the development of Material microscale damage. When the region of nonlinear Material is large, incidence of ultrasound on the interface between the perfectly joined regions of linear and nonlinear Material behavior produces very useful information. Using the continuity condition of stress and displacement at the interface, the harmonics in the nonlinear region, together with the compensatory waves, yield a reflected wave whose amplitude contains the defining constant of the Material Nonlinearity near the interface. The compensatory waves are introduced to ensure the continuity conditions at the interface. When the nonlinear region is an inclusion, the equivalent body force induced by the Material Nonlinearity generates a backscattered wave. The backscattered wave is determined in a simple manner by the use of the reciprocity theorem of elastodynamics. The backscattered wave obtained in this manner yields information on the nonlinear Material properties and the size of the inclusion. In addition, a model based on the superposition of back-propagated compensatory waves from the two interfaces of the nonlinear region reveals the physical mechanism of wave scattering from the nonlinear inclusion.

  • analysis of harmonics propagating in pipes of quadratic Material Nonlinearity using shell theory
    International Journal of Solids and Structures, 2017
    Co-Authors: Yanzheng Wang, Weiqiu Chen, Jan Drewes Achenbach
    Abstract:

    Abstract Higher harmonics in pipes of quadratic nonlinear Material behavior have been analyzed in this paper. Using shell theory, the mixing of axisymmetric longitudinal waves and torsional waves, and the self-interaction of axisymmetric longitudinal waves, have been investigated. The dispersion curves of longitudinal waves derived from the linear version of the governing equations show excellent agreement with the corresponding curves obtained from thick shell theory and three dimensional theory, presented elsewhere. For torsional waves, only the lowest mode is taken into consideration. Using the perturbation method, analytical expressions for the resonant torsional waves generated by the mixing of longitudinal and torsional waves have been obtained. The resonant waves with difference frequencies propagate in the opposite direction of the corresponding primary wave. The back-propagation effect has potential application for nondestructive evaluation. The nonlinear shell theory is further simplified for applicability to thin pipes, to obtain expressions for the cumulative second longitudinal harmonics generated by self-interaction of longitudinal waves. For this case, the phase-match conditions, which are used to determine phase-match points, are also presented in analytical form.

  • the effect of cubic Material Nonlinearity on the propagation of torsional wave modes in a pipe
    Journal of the Acoustical Society of America, 2016
    Co-Authors: Yanzheng Wang, Jan Drewes Achenbach
    Abstract:

    The effect of cubic Material Nonlinearity on the propagation in a pipe of the lowest axially symmetric torsional wave mode has been investigated in this paper. Two cases, one that the Material of the whole pipe is nonlinear, and the second that a small segment of the pipe is nonlinear, have been considered. For the first case, a first and a third harmonic have been obtained by the perturbation method. Analytical expressions for the two cumulative harmonics have been derived. The second case leads to a scattering problem. The segment produces nonlinear terms in the equation of motion, which can be regarded as a distribution of body forces. The problem is then reduced to a linear scattering problem. An analytical expression for the backscattered wave can be easily obtained by using the elastodynamic reciprocity theorem. Due to the low amplitude of the backscattered wave, the authors propose to add another higher frequency wave to the primary wave, to increase the total magnitude of the scattered wave. An example that the originally scattered wave is amplified 50 times by selecting proper frequencies is presented. Both cases considered here have a potential application to determine the Material properties in a region of nonlinear Material behavior.The effect of cubic Material Nonlinearity on the propagation in a pipe of the lowest axially symmetric torsional wave mode has been investigated in this paper. Two cases, one that the Material of the whole pipe is nonlinear, and the second that a small segment of the pipe is nonlinear, have been considered. For the first case, a first and a third harmonic have been obtained by the perturbation method. Analytical expressions for the two cumulative harmonics have been derived. The second case leads to a scattering problem. The segment produces nonlinear terms in the equation of motion, which can be regarded as a distribution of body forces. The problem is then reduced to a linear scattering problem. An analytical expression for the backscattered wave can be easily obtained by using the elastodynamic reciprocity theorem. Due to the low amplitude of the backscattered wave, the authors propose to add another higher frequency wave to the primary wave, to increase the total magnitude of the scattered wave. An ex...

Y Jiang - One of the best experts on this subject based on the ideXlab platform.

  • strength simulation of woven fabric composite Materials with Material Nonlinearity using micromechanics based model
    Journal of Thermoplastic Composite Materials, 2003
    Co-Authors: A Tabiei, G Song, Y Jiang
    Abstract:

    The objective of the current investigation is to predict failure strength of woven composites, which considers the 2D extent of woven fabric, based on micro-mechanics. The formulation has an interface with nonlinear finite element codes. At each load increment, global stresses and strains are communicated to the representative cell and subsequently distributed to each subcell. Once stresses and strains are associated to a subcell they can be distributed to each constituent of the subcell (i.e., fill, warp, and resin). Consequently, micro-failure criteria (MFC) are defined for each constituents of a subcell and the proper stiffness degradation is modeled. Different stages of failure such as warp transverse failure, fill transverse failure, failure of pure matrix in longitudinal and shear, shear failure in fill and warp, and fiber in fill and warp in longitudinal tension are considered. Good correlation is observed between the predicted and the experimental results presented in the published literature. Thi...

  • woven fabric composite Material model with Material Nonlinearity for nonlinear finite element simulation
    International Journal of Solids and Structures, 1999
    Co-Authors: A Tabiei, Y Jiang
    Abstract:

    Abstract The objective of the current investigation is to develop a simple, yet generalized, model which considers the two-dimensional extent of woven fabric, and to have an interface with nonlinear finite element codes. A micromechanical composite Material model for woven fabric with nonlinear stress-strain relations is developed and implemented in ABAQUS for nonlinear finite element structural analysis. Within the model a representative volume cell is assumed. Using the iso-stress and iso-strain assumptions the constitutive equations are averaged along the thickness direction. The cell is then divided into many subcells and an averaging is performed again by assuming uniform stress distribution in each subcell to obtain the effective stress–strain relations of the subcell. The stresses and strains within the subcells are combined to yield the effective stresses and strains in the representative cell. Then this information is passed to the finite element code at each Material point of the shell element. In this manner structural analysis of woven composites can be performed. Also, at each load increment global stresses and strains are communicated to the representative cell and subsequently distributed to each subcell. Once stresses and strains are associated to a subcell they can be distributed to each constituent of the subcell i.e. fill, warp, and resin. Consequently micro-failure criteria (MFC) can be defined for each constituent of a subcell and the proper stiffness degradation can be modeled if desired. This Material model is suitable for implicit and could be modified for explicit finite element codes to deal with problems such as crashworthiness, impact, and failure analysis under static loads.