Noncontact measurement of ultrasonic attenuation during rotating fatigue test of steel

Ogi, Hirotsugu; Hirao, Masahiko; Minoura, Kiyoshi

doi:10.1063/1.365489

Cited by 52 publications

(18 citation statements)

References 16 publications

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“…Thus, together with the applicability to in situ monitoring, intensive studies have been made using EMAR to detect the evolution of internal friction at elevated temperatures, 18,19 during deformation, 25 recovery, 26 and fatigue. 27 Here, we compare the internal friction measured by EMAR and RUS. In RUS measurements, internal friction is usually obtained from the resonance peak width: Q Ϫ1 ϭ⌬ f / f r , where ⌬ f denotes the peak width at the half-power amplitude and f r resonance frequency.…”

Section: The Internal Frictionmentioning

confidence: 99%

Contactless mode-selective resonance ultrasound spectroscopy: Electromagnetic acoustic resonance

Ogi

Ledbetter²,

Kim³

et al. 1999

The Journal of the Acoustical Society of America

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106

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A noncontacting resonant-ultrasound-spectroscopy (RUS) method for measuring elastic constants and internal friction of conducting materials is described, and applied to monocrystalline copper. This method is called electromagnetic acoustic resonance (EMAR). Contactless acoustic coupling is achieved by energy transduction between the electromagnetic field and the ultrasonic vibrations. A solenoidal coil and static magnetic field induce Lorentz forces on specimen surfaces without using a coupling agent. By changing the field direction, a particular set of vibration modes can be selectively excited and detected, an advantage in identifying the vibration modes of the observed resonance peaks. Contactless coupling allows the measure of intrinsic internal friction free from energy loss associated with contact coupling. The elastic constants and internal friction measured by EMAR are compared with those by the usual RUS method for a rectangular-parallelepiped copper monocrystal. Both methods yielded the same elastic constants despite fewer resonant peaks in the EMAR case. The two methods gave essentially the same shear-mode internal friction, but the RUS method gave higher volume-mode internal friction.

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Section: The Internal Frictionmentioning

confidence: 99%

Contactless mode-selective resonance ultrasound spectroscopy: Electromagnetic acoustic resonance

Ogi

Ledbetter²,

Kim³

et al. 1999

The Journal of the Acoustical Society of America

Self Cite

106

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“…[11] No study average grain size of the aluminum specimen was 38 m. has reported such a peak, despite the long history of research. The attenuation peak appearing at the final stage.…”

Section: Introductionmentioning

confidence: 99%

Ultrasonic attenuation peak in steel and aluminum alloy during rotating bending fatigue

Ogi

Hamaguchi

Hirao

2000

Metall Mater Trans A

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HIROTSUGU OGI, TAKAYUKI HAMAGUCHI, and MASAHIKO HIRAO Using electromagnetic acoustic resonance (EMAR), we studied the evolution of the surface shearwave attenuation and phase velocity in a 0.45 pct C steel and a 5052 aluminum alloy exposed to rotating bending fatigue. In the EMAR method, we used electromagnetic acoustic transducers (EMATs) for the contactless measurements of the axial shear wave, which is a surface shear wave that propagates along a cylindrical surface in the circumferential direction, with an axial polarization. There has been no previous report of continuous and contactless monitoring of the surface wave attenuation and velocity being performed without interrupting the fatigue. The attenuation coefficient always showed sharp peaks around 90 pct of the fatigue life, independent of the fatigue-stress amplitude. To interpret this phenomenon, we made crack-growth observations using replicas and measurements of recovery of attenuation and velocity by stopping the cyclic loading before and after the peak. From these results, we concluded that the evolution of the ultrasonic properties is caused by a drastic change in dislocation mobility being accompanied by the crack growth at the final stage of the fatigue life.

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“…For instance, Ogi et al monitored the fatigue damage process of steel pipes by measuring the surface-shearwave attenuation using an electromagnetic acoustic transducer (EMAT) and concluded that the dislocation mobility is the principal source of the attenuation change and that dislocations play an important role in crack growth. 6,7) From the comparison of the ultrasonic attenuation among Fig. 7, the attenuation in lower ultrasonic frequency was larger than that in higher ultrasonic frequency.…”

Section: Ultrasonic Attenuation In Discrete Frequency Componentsmentioning

confidence: 99%

Detection Method of Fatigue Damage in Carbon Steel Using Laser Ultrasonics

Tanaka¹,

Izawa²

2002

Journal of Nuclear Science and Technology

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Ultrasonic attenuation was measured by the laser ultrasonic technique among the carbon steel specimens which were subjected to five stages of fatigue damage by constant cyclic tensile stress amplitude. Irradiation of a Q-switched laser was used for ultrasonic generation, and a laser interferometer which consists of a frequency-doubled continuous wave laser and a Fabry-Perot etalon was used for detection of ultrasonic vibration on the specimen surface. From the comparison of the broadband ultrasonic waveforms among five stages of fatigue damage, the attenuation coefficient of the longitudinal wave by the intrinsic material attenuation increased progressively with increasing the number of fatigue cycle. Ultrasonic attenuation at 2.5, 5.0, 7.5 and 10.0 MHz were also calculated by Fourier transformation in order to compare the decay of the longitudinal wave among these frequency components. From the results, ultrasonic attenuation increased as the number of fatigue cycle increased, in both broadband and narrowband frequency components. Therefore, the measurement of broadband and narrowband ultrasonic wave obtained by the laser ultrasonic technique would be effective as the detection method of fatigue damage in nuclear power plant components.

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Noncontact measurement of ultrasonic attenuation during rotating fatigue test of steel

Cited by 52 publications

References 16 publications

Contactless mode-selective resonance ultrasound spectroscopy: Electromagnetic acoustic resonance

Contactless mode-selective resonance ultrasound spectroscopy: Electromagnetic acoustic resonance

Ultrasonic attenuation peak in steel and aluminum alloy during rotating bending fatigue

Detection Method of Fatigue Damage in Carbon Steel Using Laser Ultrasonics

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