摘要:

Quantitative acoustic microscopy involves the measurement of the Voltage-Defocus response or theV(z) response followed by subsequent analysis to extract material characteristics such as surface wave velocity and attenuation. An amplitude and phase measuring acoustic microscopy system has been developed with commercially available tone-burst equipment for accurate mono-frequency measurements in the 20–150MHz regime. The Rayleigh wave velocities of various materials were extracted using the new system and these were in good agreement with the published values.

ISSN:1058-9759    

DOI:10.1080/10589759708953024

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Surface cracks and artificial volume defects in silicon nitride ceramic valves were studied using high-frequency ultrasound in the 10–80MHz range. The volume defects were pores of l00μm diameter. A focusing transducer with a focal length of 25 mm in water was operated in pulse-echo technique. Longitudinal, and mode converted transverse and Rayleigh waves were excited in the ceramic by variation of the angle of incidence of the sound beam in water. The echo amplitude of individual defects was studied as a function of the angle of incidence and defect depth. The amplitude of the backscattered longitudinal wave from the defect was always higher than that of the backscattered transverse wave. Leaky Rayleigh wave signals from surface cracks were obtained over a range of angles of incidence much beyond the calculated angle for a plane wave.

ISSN:1058-9759    

DOI:10.1080/10589759708953025

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

Theoretical research of ultrasonic wave propagation in austenitic steel welds was performed and integral equations were applied to the problem of planar ultrasonic wave scattering in anisotropic polycrystal medium. The problem was solved using the Born approximation and analytical calculations were carried out for an austenitic metal weld and the weld thermal influence zone. The calculated values for scattering coefficients were used for calculating the attenuation of ultrasonic signals passing through austenitic welds. Energetic and geometric factors of ultrasonic wave intensity attenuation in austenitic welds were considered and formulas to calculate the deviation angle of the acoustic beam from wave normal and acoustic beam deformation coefficients in a weld were obtained as well. With the example of a single V-butt weld in 12H18N10T steel (analogous 321 H steel) a calculation of the value of ultrasonic signal attenuation and a prediction of the ultrasonic beam outcoming point location were carried out in the present work.

ISSN:1058-9759    

DOI:10.1080/10589759708953026

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The effect of skew-angle magnetic field concentrators with a uniform distribution of magnetic charge density upon the normal component value of the magnetic field over a rectangular slot has been studied. It is shown how, under the set slot parameters, there is an optimal concentrator thickness, and the magnetic field tangential component reaches its maximum.

ISSN:1058-9759    

DOI:10.1080/10589759708953027

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor

摘要:

The physical phenomena responsible for the developing process during penetrant testing using liquid phase developers are analysed in this paper. It is shown that the developers's liquid phase intensively affects the developing process. The main physical parameters of the liquid phase that determine liquid drawing out of a capillary channel, taking into account the channel geometry, are found. A relation is derived to calculate the degree of filling in the capillary channel when liquid phases interact. This relation allows one to compare the sensitivity of different penetrant systems used for penetrant testing, and it also permits one to correctly choose substances for technologies employing the consecutive contact of liquids with capillary-porous bodies. A new means is proposed to demonstrate how to determine the pressure of saturated vapours of complex composition liquids.

ISSN:1058-9759    

DOI:10.1080/10589759708953028

出版商:Taylor & Francis Group    

年代:1997

数据来源: Taylor