نتایج جستجو برای: ultrasonic nondestructive examinations
تعداد نتایج: 70280 فیلتر نتایج به سال:
Continuous ultrasonic in-situ monitoring for industrial applications is difficult owing to the high operating temperatures in industrial fields. It is expected that ultrasonic transducers consisting of a CaBi₄Ti₄O15(CBT)/Pb(Zr,Ti)O₃(PZT) sol-gel composite could be one solution for ultrasonic nondestructive testing (NDT) above 500 °C because no couplant is required and CBT has a high Curie tempe...
The estimation of the time of arrival (TOA) and/or time of flight of the ultrasonic echoes is essential in ultrasonic nondestructive evaluation. In this paper, matching pursuit method has been used to analyze noisy ultrasonic pulse-echo wavelet and decompose the noisy pulse-echo wavelet into unit-norm vectors. The error ratio of the mean square is used to monitor the acceptability of the unit-n...
The pulse compression technique is successfully and widely used in many fields for improving the signal to noise ratio (SNR); which is especially useful when the environment is noisy and the SNR is poor. Since high frequency ultrasound is strongly attenuated in concrete, only low frequency ultrasound can be used in ultrasonic nondestructive testing (NDT) of concrete. In this study the pulse com...
Ultrasonic imaging for nondestructive evaluation (NDE) applications is an important process for industrial applications. Understanding the material structure is an integral part of the manufacturing as well as maintenance operations. Especially for the critical industries like airlines where each component of the aircraft is required to perform at its best. One way to analyze material samples f...
Coatings play a crucial role in protecting ships and marine structures from corrosion extending their service life. The reliability of these coatings depends on proper maintenance, which turn, relies the application reliable diagnostic techniques. Non-destructive testing (NDT) techniques are useful material diagnostics, such as detecting debonded zone water. However, challenging access environm...
Acoustical methods are playing an important role for nondestructive evaluation (NDE) of adhesive-bonded composites and components in industrial applications. A dual-frequency ultrasonic technique is proposed for the quantitative evaluation of contact strength between pressed solid surfaces. An ultrasonic excitation consists of two primary frequency components is applied perpendicular to the int...
Drilling boreholes is common practice in geotechnical and geoenvironmental investigations and in various other ex ploration, testing, and monitoring appli cations. When a casing is placed in a borehole an annular space is created be tween the casing and the surrounding soil. If not properly sealed, this annular space can be a potential path for trans port of contaminants in the subsurface e...
Ultrasonic guided waves are used to detect the delamination between skin and honeycomb of a composite helicopter rotor blade. Theoretical work is carried out for guided waves in the trailing edge of a rotor blade, which is a multilayer composite skin/NOMEX half space structure. The dispersion relation is obtained with the global matrix method. Theoretically driven experiments are conducted on a...
In this paper, the inverse problem of reconstructing reflectivity function of a medium is examined within a blind deconvolution framework. The ultrasound pulse is estimated using higher-order statistics, and Wiener filter is used to obtain the ultrasonic reflectivity function through wavelet-based models. A new approach to the parameter estimation of the inverse filtering step is proposed in th...
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