Results 261 to 270 of about 52,181 (311)

Ultrasonic absortion in fatigued materials

AIP Conference Proceedings, 2013
Non-destructive detection of fatigue damage, allowing an estimate of the residual life-time of components, could contribute to a safe and reliable operation of components and installations. Ultrasonic absorption, i.e. the internal friction, of a material increases with increasing fatigue or creep damage and there are many theories trying to explain the
S. Dugan, W. Arnold
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Ultrasonic response to material fatigue

SPIE Proceedings, 2001
In many engineering materials micro-cracks develop when the materials are subjected to repeated loading or fatigue loading. These micro-cracks increase the material attenuation and alter the ultrasonic wave speed. Careful experiments show that as a material is subjected to a greater number of fatigue cycles, its higher order (also known as the ...
Young-Chul Jung, Tribikram Kundu
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Fatigue and Ultrasonic Attenuation

1957
Experiments conducted in this laboratory over the past several years have shown that appreciable changes occur in the propagation and recovery behavior of ultrasonic waves in materials during stress or fatigue cycling. Although most of the exploratory work has been done on three types of aluminum, the method is not restricted to aluminum. The following
Rohn Truell, Akira Hikata
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FATIGUE CRACK GROWTH UNDER ULTRASONIC FATIGUE LOADING

Fatigue & Fracture of Engineering Materials & Structures, 1997
Abstract— In this paper, a stress and modal analysis of an ultrasonic vibration system consisting of a notched specimen and one or two amplifying horns have been performed by using 3D finite element calculations. The stress intensity factors in ultrasonic fatigue crack propagation are evaluated by means of displacement and energy approaches.
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Recent developments in ultrasonic fatigue

Fatigue & Fracture of Engineering Materials & Structures, 2015
AbstractThe recently increased interest in very high cycle fatigue properties of materials has led to extended use and further development of the ultrasonic fatigue testing technique. Specimens are stimulated to resonance vibrations at ultrasonic frequency, where the high frequency allows collecting lifetime data of up to 1010cycles and measuring crack
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Ultrasonic Evaluation of Fatigue Damage

AIP Conference Proceedings, 2004
Despite the fact that most engineers and designers are aware of fatigue, many severe breakdowns of industrial plant and machinery still occur due to fatigue. In effect, it’s been estimated that fatigue causes at least 80% of the failures in modern engineering components.
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High-power, ultrasonic fatigue testing machine

Review of Scientific Instruments, 1975
A machine capable of fatigue testing high strength alloys at an ultrasonic frequency (20 kHz), and a range of temperatures likely to be encountered by such materials in aerospace and power generation applications and in basic research, is described.
J. K. Tien, S. Purushothaman, R. M. Arons, J. P. Wallace, O. Buck, H. L. Marcus, R. V. Inman, G. J. Crandall   +7 more
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Direct ultrasonic visualization of fatigue cracks

NDT International, 1980
Abstract The advantages of direct ultrasonic visualization over conventional pulse-echo methods in detecting and characterizing fatigue cracks is demonstrated. It is shown that visualization is especially advantageous when the plane of the crack is not perpendicular to the ultrasound beam.
Y. Bar-Cohen, S. Kovnovish, E. Harnik
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Fatigue Crack Characterization by Ultrasonic Inspection

Journal of Testing and Evaluation, 1990
Abstract The ultrasonic interrogation of components for the detection and sizing of defects has advantages over other techniques in that surface as well as subsurface defects can be probed. However, the phenomenon of crack closure or crack surface contact can reduce the detectability of a crack and lead to erroneous crack sizing.
DK Rehbein, RB Thompson, O Buck
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Ultrasonic fatigue of Cu-single crystals

Scripta Metallurgica, 1984
Comparaison des courbes contrainte-deformation en presence ou non d'ultrasons. On observe une legere variation de la transition elastoplastique explicable par le fait que la contrainte mecanique, de traction ou de compression, en fatigue, est mal definie en presence d ...
L. Buchinger, K. Kromp, G. Schoeck
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