Results 251 to 260 of about 63,045 (293)
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Nonlinear ultrasonic inspection of friction stir welds
2015Nonlinear ultrasonic approach combined with pulse inversion method is applied for interpretation of the damage status of kissing bonds contacts in friction stir welds.
Tabatabaeipour, M. +3 more
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Nonlinear Ultrasonic Damage Characterization of Limestone
Research in Nondestructive Evaluation, 2016ABSTRACTCharacterization of dolomitic limestone rock samples with increasing levels of damage is presented using a nonlinear ultrasonic approach. Limestone test samples with increasing levels of damage were created artificially by exposing virgin samples to increasing temperature levels of 100, 200, 300, 400, 500, 600, and 700°C for a ninety minute ...
Megan E. McGovern, Henrique Reis
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Nonlinear Ultrasonic Evaluation of Concrete Microcracking
AIP Conference Proceedings, 2004Microcracking is usually associated with most types of concrete deterioration. The nondestructive detection of deterioration in in‐situ concrete in its early stages is not practical using current technology. In this project nonlinear ultrasound was used to evaluate the degree of microcracking changes resulting from increasing compression stresses ...
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Nonlinear behavior of an ultrasonic transducer
Ultrasonics, 1996A transducer model, based on nonlinear piezoelectric constitutive equations, has been developed to describe the harmonic generation that occurs on current or velocity signal analysis when the transducer is driven at high voltage. The symmetrical Langevin transducer studied close to its resonance frequency is composed of Navy III type power ceramics ...
N. Aurelle +4 more
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Nonlinear Ultrasonic Techniques for Material Characterization
2018This chapter considers both the theoretical aspects of the nonlinear ultrasonic phenomena in elastic solids and their applications to materials characterization; it has been demonstrated that nonlinear ultrasound (NLU) measurements can provide quantitative inputs to determine the material state and measure damage in engineering components.
J.-Y. Kim, L. Jacobs, J. Qu
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Nonlinear ultrasonic propagation in biological media.
The British journal of cancer. Supplement, 1982The nonlinearity parameter B/A for several biological materials was determined by measuring the amplitude of the second harmonic pressure as a function of distance from the source and the amplitude of the fundamental at the source. The B/A values for bovine serum albumin and haemoglobin solutions were found to increase approximately linearly with ...
F, Dunn, W K, Law, L A, Frizzell
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Nonlinear dislocation dynamics at ultrasonic frequencies
Journal of Applied Physics, 2009An analytical model of the effects of the Peierls–Nabarro barrier stress on the nonlinear dynamics of dislocation motion in crystalline solids resulting from a perturbative ultrasonic wave is derived. The nonlinearity is quantified by a material nonlinearity parameter β extracted from measurements of the amplitudes of the fundamental and harmonically ...
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Ultrasonic nonlinear imaging at fundamental frequencies
The Journal of the Acoustical Society of America, 2003Nonlinear tissue or contrast agent effects are detected by combining echoes from multiple, differently modulated transmit pulses below the second harmonic band. The received echoes may even overlap the fundamental transmit frequency band. The modulation may be amplitude modulation or phase or polarity modulation, and is preferably both amplitude and ...
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Nonlinear ultrasonic effects in adhesive joints
AIP Conference Proceedings, 2001Various theoretical investigations and experiments were performed to study the nonlinear interaction of an acoustic wave with an adhesive joint. In the case of resonance, the adhesive layer contributes significantly to the second harmonic A2. The amplitude of A2 strongly depends on the adhesive layer thickness and the sound velocity.
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Numerical Study of Nonlinear Ultrasonic Resonators
AIP Conference Proceedings, 2006In the framework of high‐power ultrasonic applications, this communication deals with the numerical simulation of nonlinear resonators. The objective is the understanding of the behavior of nonlinear acoustic waves in resonant cavities. For this purpose several models are developed in the time domain.
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