Evaluation of muscle fatigue state by ultrasonic attenuation coefficient

It was attempted to assess nondestructively the degree of isothermal degradation of 2.25Cr-1Mo steel by using high frequency longitudinal ultrasonic wave. Microstructural parameter (mean size of carbides), mechanical property (Vickers hardness) and ultrasonic attenuation coefficient were measured for the 2.25Cr-1Mo steel isothermally degraded at 630°C for up to 4800 hours in order to find the correlation among these parameters. The ultrasonic attenuation coefficients at high frequencies (over 35MHz) were observed to increase rapidly in the initial 1000 hours of degradation time and then slowly thereafter, while the ones at low frequencies showed no noticeable increase. Ultrasonic attenuation at high frequencies increased as a function of mean size of carbides. Ultrasonic attenuation coefficient was found to have a linear correlation with the hardness, and suggested accordingly as a potential nondestructive evaluation parameter for assessing the mechanical strength reduction of the isothermally degraded 2.25Cr-1Mo steel.

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A MEASUREMENT OF ULTRASONIC ATTENUATION COEFFICIENT BY FREQUENCY RESPONSE IN STEELS WITH DIFFERENT GRAIN SIZES

Transactions of the Canadian Society for Mechanical Engineering ◽

10.1139/tcsme-2002-0023 ◽

2003 ◽

Vol 26 (4) ◽

pp. 389-402

Author(s):

Kyung-Cho Kim

Keyword(s):

Frequency Response ◽

Attenuation Coefficient ◽

Evaluation Method ◽

Ultrasonic Attenuation ◽

Wave Length ◽

Structural Behavior ◽

Response Property ◽

Sound Waves ◽

Grain Sizes ◽

Plate Specimen

A new evaluation method of ultrasonic attenuation in materials is proposed based on the frequency response property of the material evaluated by employing the sound impulse of a wide frequency band. Borrowing from ordinary system theory, the material to be tested is considered to have a characteristic impulse response, representing its micro-structural non-uniformities and thus resulting in the sound attenuation of the material. The concept is resumed as an attenuation system that simulates the material’s micro-structural behavior. Experimental results on a series of specimens, having different grain sizes but all made of a single austenitic stainless steel, showed that the attenuation could properly be evaluated from a single bottom echo in a plate specimen. The attenuation coefficient α, was corrlated in this case to the grain size, D, by the equation, αD=H(πD/λ)n, where λ is wave length and H and n are constants. It was also shown that the micro structural change of materials could be evaluated by the energy loss of sound waves passing through the attenuation systems.

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Phase insensitive ultrasonic attenuation coefficient determination of fresh bovine liver over an extended frequency range

Medical Physics ◽

10.1118/1.595030 ◽

1981 ◽

Vol 8 (5) ◽

pp. 692-694 ◽

Cited By ~ 41

Author(s):

J. D. Pohlhammer ◽

C. A. Edwards ◽

W. D. O'Brien

Keyword(s):

Attenuation Coefficient ◽

Ultrasonic Attenuation ◽

Bovine Liver ◽

Frequency Range ◽

Extended Frequency Range ◽

Extended Frequency

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543: Ultrasonic attenuation coefficient of the cervix in women receiving ultrasound indicated cerclage: a pilot study

American Journal of Obstetrics and Gynecology ◽

10.1016/j.ajog.2015.10.587 ◽

2016 ◽

Vol 214 (1) ◽

pp. S292-S293

Author(s):

Yvette Cordova ◽

Aiguo Han ◽

William D. O'Brian ◽

Samadh H. Ravangard ◽

Michelle A. Kominiarek ◽

...

Keyword(s):

Pilot Study ◽

Attenuation Coefficient ◽

Ultrasonic Attenuation

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Measurement of ultrasonic attenuation coefficient in polymer gel dosimeters

Physics in Medicine and Biology ◽

10.1088/0031-9155/48/20/n01 ◽

2003 ◽

Vol 48 (20) ◽

pp. N269-N275 ◽

Cited By ~ 48

Author(s):

Melissa L Mather ◽

Paul H Charles ◽

Clive Baldock

Keyword(s):

Attenuation Coefficient ◽

Ultrasonic Attenuation ◽

Polymer Gel

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Micro-Structural Monitoring of 2.25Cr-1Mo Steel by Surface SH Wave

Ultrasonic Nondestructive Evaluation for Material Science and Industries ◽

10.1115/pvp2003-1853 ◽

2003 ◽

Author(s):

Ik-Keun Park ◽

Youn-Ho Cho

Keyword(s):

Attenuation Coefficient ◽

Thermal Damage ◽

Thermal Environment ◽

Ultrasonic Attenuation ◽

Subsurface Layer ◽

Horizontal Displacement ◽

Sh Wave ◽

Nondestructive Technique ◽

Near Surface ◽

Materials Used

The feasibility of SH (shear horizontal) waves for monitoring thermally degraded materials is explored. It turns out that the use of SH waves leads to a promising nondestructive technique for the purpose of microstructure evaluation and material characterization of such materials. This is because SH modes can interact with entire surface and subsurface area of specimen that is mainly exposed to severe thermal environment, while a conventional point-by-point technique is confined to just local investigations, underneath a transducer. Consequently, SH modes’ data can show a better sensitivity and provide us with various features for thermal damage evaluation, compared to ones of local inspection, which results in the enhancement of experimental reliability. 2.25Cr-1Mo steel specimens for various degradation levels were prepared by isothermal aging heat treatment at 650° and evaluated by the present technique to investigate the influence of thermal damage to the SH wave feature based on the attenuation coefficients. Discussed is monitoring for thermally degraded structural materials used at high temperature by the surface SH-wave propagating along near surface and subsurface layer with horizontal displacement polarization. Because of the carbide precipitation increase and spheroidization near the grain boundary of a microstructure to aging degradation, the attenuation coefficient had a tendency to increase as degradation proceeded. It was identified possibly to evaluate degradation using the characteristics of the attenuation coefficient and amplitude spectra through Fast Fourier Transform (FFT) analysis. Frequency dependence of the ultrasonic attenuation coefficient to aging degradation appeared large, which made sure that the attenuation coefficient can be an important parameter for the evaluation of aging.

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