On The Behavior Of Nonlinear Ultrasonic Waves In Water-air Mixtures

2008 ◽  
Author(s):  
Christian Vanhille ◽  
Cleofé Campos-Pozuelo ◽  
Bengt Enflo ◽  
Claes M. Hedberg ◽  
Leif Kari
Keyword(s):  
Ultrasonic Waves ◽  
Nonlinear Ultrasonic

Measurement of Natural Vibrations and Resonant Second Higher-Harmonics Due to a Fatigue Crack

2020 ◽  
Vol 3 (4) ◽  
Author(s):  
Kosuke Kanda ◽  
Shan Lin
Keyword(s):  
Fatigue Crack ◽  
Frequency Response ◽  
Ultrasonic Testing ◽  
Characteristic Curve ◽  
Ultrasonic Waves ◽  
Local Defect ◽  
Response Characteristics ◽  
Local Defect Resonance ◽  
Nonlinear Ultrasonic ◽  
Frequency Response Characteristics

Abstract Nonlinear ultrasonic testing is considered a more promising technique for evaluating closed cracks than conventional ultrasonic testing. However, the mechanism of the generation of nonlinear ultrasonic waves has not been sufficiently explained. We first set up a system to measure the frequency–response characteristics of ultrasonic waves and experimentally investigated the mechanism of second higher-harmonic (HH) wave generation for a fatigue crack. Sweeping the frequencies of incident waves impinging on a fatigue crack introduced to a specimen, we obtained a frequency–response characteristic curve for the crack. From the curve, resonance phenomena resulting from local defect resonance were observed. We then measured the frequency response characteristics of second HH waves using the same system and consequently confirmed that second HH waves resonated when their frequencies corresponded to the eigenfrequencies of the crack. Finally, we theoretically showed that the resonant second HH waves were generated by local defect resonance and nonlinearity.

scholarly journals Nonlinear ultrasonic waves in water‐air mixtures

2008 ◽  
Vol 123 (5) ◽  
pp. 3704-3704
Author(s):  
Christian Vanhille ◽  
Cleofé Campos‐Pozuelo
Keyword(s):  
Ultrasonic Waves ◽  
Nonlinear Ultrasonic

Imaging the Nonlinear Ultrasonic Parameter of a Medium

1983 ◽  
Vol 5 (4) ◽  
pp. 295-299 ◽  
Author(s):  
Nobuyuki Ichida ◽  
Takuso Sato ◽  
Melvin Linzer
Keyword(s):  
Spatial Frequency ◽  
Probe Beam ◽  
Pump Wave ◽  
Power Level ◽  
Ultrasonic Waves ◽  
Nonlinear Parameter ◽  
Probe Wave ◽  
Cross Sectional ◽  
Nonlinear Ultrasonic ◽  
Ultrasonic Parameter

A technique for imaging the nonlinear ultrasonic parameter B/A has been developed. The nonlinear parameter describes the dependence of ultrasonic velocity on pressure and may well provide a new and powerful tool for characterizing both biological and nonbiological media. Our approach is based on observing the interaction of two ultrasonic waves with different frequencies and power levels. A low frequency pump wave, with power level suitable for medical diagnosis (1 mW/cm2), is used to sinusoidally modulate the sound pressure over the region of interest. A much lower intensity high-frequency probe beam is propagated perpendicularly to the pump beam. The phase of the probe wave is modified in proportion to the integral of the product of the nonlinear parameter B/A and the pressure of the pump wave, which varies sinusoidally along the probe beam. This phase change provides a Fourier component of the distribution of the nonlinear parameter B/A for the spatial frequency corresponding to the inverse of the pump wavelength. By changing the frequency of the pump waves, the spatial frequency is changed and a set of spatial Fourier coefficients of the distribution of the nonlinear parameter B/A is obtained. An inverse operation then gives the one-dimensional image along the probe beam. If the probe beam is scanned mechanically, the entire cross-sectional image is obtained. Several images of the nonlinear parameter of biological objects were generated with our system. To our knowledge, these represent the first images of the nonlinear parameter to be reported in the literature. The nonlinear parameter of water was also measured and agreed well with values obtained by other techniques.

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