Long wavelength approximation for Lamb wave characterization of composite laminates

Tang, B.; Henneke, E. G.

doi:10.1007/bf01607869

Cited by 10 publications

(12 citation statements)

References 11 publications

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“…Since the lowest antisymmetric pulse does not travel fast enough to return to the receiver this frequently, it is clear that higher plate modes now are being excited. Plate wave dispersion diagrams reveal that they are very disperse and travel much slower [6], [7]. A collection of these higher plate mode arrivals has the randomness in phase and amplitude that is desirable for UD.…”

Section: Resultsmentioning

confidence: 96%

“…One induces an exponentially decaying signal to arrive at the receiver, which then is collected and analyzed. It may happen that the presence of nondispersive--or nearly nondispersive--plate modes will produce components in the signal with well-defined velocity and phase [6], [7]; this is undesirable for the present application. One may be able to avoid this by using frequency filtering or by using only a segment of the time domain.…”

Section: Theory and Experimentsmentioning

confidence: 95%

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Acousto-ultrasonic decay in metal matrix composite panels

Kautz¹

1996

Res Nondestr Eval

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Acousto-ultrasonic (A-U) decay rates (UD) were measured in metal matrix composite (MMC) panels. The MMC panels had fiber architectures and cross-sectional thicknesses corresponding to those designed for aerospace turbine engine structures. The wavelength-to-thickness ratio produced by the combination of experimental frequency setting conditions and specimen geometry was found to be a key parameter for identifying optimum conditions for UD measurements. The ratio was shown to be a useful rule of thumb when applied to ceramic matrix composites (CMC)s and monolithic thermoplastics.

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Section: Resultsmentioning

confidence: 96%

Section: Theory and Experimentsmentioning

confidence: 95%

Acousto-ultrasonic decay in metal matrix composite panels

Kautz¹

1996

Res Nondestr Eval

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“…As a result, it will be more viable and reliable to measure the very small changes in ultrasonic wave velocities in the frequency domain caused by the stress field. Since its discovery in the 1980s, the LLW technology has been applied for many NDE applications, such as the measurement of material properties [6], the cohesive properties of bonds [5], and the properties of composite materials [7]. However, the key parameters in the LLW dispersion equation, such as the plate thickness, density, and longitudinal and transverse ultrasonic wave velocities, are coupled in the symmetric and antisymmetric Lamb wave modes, and cannot be decoupled easily in general [8].…”

Section: Introductionmentioning

confidence: 98%

“…However, the key parameters in the LLW dispersion equation, such as the plate thickness, density, and longitudinal and transverse ultrasonic wave velocities, are coupled in the symmetric and antisymmetric Lamb wave modes, and cannot be decoupled easily in general [8]. Many efforts have been devoted to the inversion of the wave equations of LLW [5,7,8]. Among them, the modal frequency spacing (MFS) method [8] decouples the wave equation parameters in a straightforward way, leading to a simple relationship between the ultrasonic wave velocity and the modal frequency spacing of two adjacent Lamb wave modes in the spectrum.…”

Section: Introductionmentioning

confidence: 99%

Stress Evaluation Using Ultrasonic Interference Spectrum of Leaky Lamb Waves

Zhu

Post

Xu³

2010

Exp Mech

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This paper presents a nondestructive stress evaluation technique using the ultrasonic interference spectrum of leaky Lamb waves. By using a specific pitch-catch ultrasonic setup, the symmetric and antisymmetric modes of Lamb waves in a finite plate are decoupled, leading to simple relationships between the modal frequency spacing of two adjacent modes in the interference spectrum and the acoustic wave velocities that are functions of stress. As a result, the stress in the plate can be determined by measuring the modal frequency spacing instead of the relative flight times to calculate the acoustic wave velocity. Extensive experiments were carried out to verify the viability and robustness of the new technique using a simple testing system. It has been demonstrated that the new technique is about 25 times more accurate than existing flight-time approaches using the same testing system. The experimental results agree well with the results obtained by other ultrasonic methods using expensive equipment.

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“…Such a requirement underlines the importance of nondestructive evaluation as a quality control tool to establish equivalence of the elastic properties of a manufactured composite to that of the designed composite. Several recent papers have been devoted to development of such nondestructive techniques, mainly based on application of bulk ultrasonic waves [1][2][3][4][5] and Lamb waves [6][7][8].…”

mentioning

confidence: 99%