Results 211 to 220 of about 13,079 (259)
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Ultrasonic nonlinearity parameter in uniaxial stress condition
Ultrasonics, 2020The ultrasonic nonlinearity parameter derived for one-dimensional propagation of a longitudinal wave in an isotropic material has been considered useful in the evaluation of material degradation. To demonstrate this, many researchers have reported on the correlation with the yield strength obtained from a tensile test.
Jongbeom Kim +3 more
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Nonlinear Multibeam Ultrasonic Imaging
2008Studies were conducted on multi-frequency ultrasonic imaging to employ simultaneous transmission of 2 and 8 MHz pulses, where the secondary waves generated through nonlinear ultrasound propagation is utilized. Multi-frequency images are constructed by using various frequency components extracted from echo signals.
I. Akiyama +3 more
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Nonlinear Ultrasonic Reciprocal Method for Damage Localisation
Structural Health Monitoring 2017, 2017Nonlinear ultrasonic techniques are based on the measurement of nonlinear elastic effects in the material, such as the magnitude of second harmonic response, in order to reveal the presence of surface and sub-surface flaws. These methods have shown to be more sensitive to damage-related structural alterations than any other ultrasonic technique, which ...
Boccardi S. +3 more
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Nonlinear Dynamics and Control of Ultrasonically Assisted Machining
Journal of Vibration and Control, 2005Nonlinear models of the cutting process with superposition of ultrasonics are proposed and investigated. It is confirmed that under the influence of high frequency vibration, the phenomenological plasticisation of brittle materials and fluidisation of dry friction occurs.
Babitsky, Vladimir, Astashev, Vladimir
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Emitter for formation of nonlinear ultrasonic waves
Proceedings of the International Scientific and Technical Symposium «Improving energy and resource efficiency and environmental safety of processes and devices in the chemical and related industries» dedicated to the 110th anniversary of A. N. Planovsky : Vol. 1, 2021The article is devoted to the development of a method for influencing aerosols with nonlinearly distorted wave packets of finite duration, determining the optimal characteristics of wave packets, before developing a new design of solid-state emitters of mechanical vibrations of ultrasonic frequency, determining the optimal geometric dimensions of these
Vladimir N. Khmelev +3 more
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2006
Abstract Up to this point, it has generally been assumed that the excitation is sufficiently small so that linearity can be assumed. In practice, for both ultrasound diagnostic and therapeutic applications, this condition is frequently exceeded. For diagnostic applications where a short, high-amplitude transmit pulse is used to obtain
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Abstract Up to this point, it has generally been assumed that the excitation is sufficiently small so that linearity can be assumed. In practice, for both ultrasound diagnostic and therapeutic applications, this condition is frequently exceeded. For diagnostic applications where a short, high-amplitude transmit pulse is used to obtain
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SPICE Modeling Nonlinearity Effects on Ultrasonic Waves
Journal of Vibration and Acoustics, 2009Nonlinearity is one of the phenomena that affect the ultrasonic wave during its propagation in a given medium. In the time domain the nonlinearity is seen as a variation of the phase velocity which leads to a distortion of the waveform. This corresponds in the frequency domain to energy transfer from the fundamental frequency to the harmonic and among ...
Noureddine Aouzale +2 more
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Imaging the ultrasonic coefficient of nonlinearity: The impact of speed of sound variations
2015 IEEE International Ultrasonics Symposium (IUS), 2015Imaging the acoustical coefficient of nonlinearity, β, is of interest in a number of healthcare interventional applications. For cardiac ablation therapy, detecting the protective fibrofatty layer between the atrial wall and the esophagus would provide risk assessment with respect to esophageal injury.
Van Sloun, Ruud Jg +3 more
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A time-resolved method for nonlinear ultrasonic measurements
Ultrasonics, 2002We describe a time-resolved method for measuring nonlinear ultrasonic phenomena. Current approaches rely on a narrowband measurement of harmonic generation to identify and characterize nonlinearity. Concomitant with these techniques is poor time resolution.
Stephen D, Holland, Wolfgang, Sachse
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Laser Ultrasonic Nondestructive Testing Based on Nonlinear Ultrasonic Coefficient
Russian Journal of Nondestructive Testing, 2020Laser ultrasonic nondestructive testing technology can effectively detect the location of cracks and other information, it is easy to realize the qualitative detection of cracks, but it is difficult to achieve quantitative detection of cracks. In this paper, based on the traditional nonlinear ultrasonic method, ultrasound excited by laser.
null Feng Qin +4 more
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