دانلود رایگان مقاله لاتین معایب دو وجهی از سایت الزویر
عنوان فارسی مقاله:
خواص معایب دو وجهی توسط تمرکز ترکیبی پرتو صدا با استفاده از آرایه های خطی
عنوان انگلیسی مقاله:
Characterization of planar flaws by synthetic focusing of sound beam using linear arrays
سال انتشار : 2015
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مقدمه انگلیسی مقاله:
1. Introduction
Planar flaws are considered harmful from the point of view of structural integrity of the pressurized components because of the stress concentration associated with them. Manufacturing processes such as forging, rolling, welding, etc. can introduce planar flaws in the component. Service induced flaws such as fatigue cracks and stress corrosion cracks are also planar flaws. A crucial parameter determining the acceptability of a planar flaw is its depth (height or through-wall dimension) [1]. The amplitude based ultrasonic methods for flaw depth estimation are prone to errors primarily because of the fact that the signal amplitude from a flaw is dependent on many factors not related to flaw depth such as orientation, roughness, transparency and coupling efficiency [2]. Advanced ultrasonic based approaches reply on locating the flaw extremities and hence are less prone to sizing errors. The time-of-flight diffraction technique uses a separate transmitter and receiver and relies on the time-of-flight of the diffracted signals from the flaw tips for depth sizing [3,4]. Synthetic Aperture Focusing Technique (SAFT) aims at locating the flaw tips and improving signal to noise ratio by carrying out post-processing of ultrasonic B-scan and C-scan images collected using a divergent sound beam [5,6]. During processing, the sound beams are time shifted or back propagated to the scattering source and averaged out using wave propagation formulae. The signal amplitude at the defect location is highly improved due to constructive interference, while at other locations the destructive interference of sound beam leads to huge drop in signal amplitude [7,8]. In the present study, an approach combining linear arrays and SAFT has been employed for characterization of planar flaws. The approach involves SAFT processing of B-scan image collected during electronic scanning using a linear array. The results of flaw characterization on a stainless steel plate with simulated planar flaws and carbon steel plates with weld planar flaws are discussed in this paper.
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کلمات کلیدی:
Nondestructive Characterization of Materials VIII https://books.google.com/books?isbn=1461548470 Robert E. Green - 2012 - Technology & Engineering The joint geometry, core materials, and defect orientation render conventional techniques unable to detect planar flaws lying below the core material. Ultrasonic and Electromagnetic NDE for Structure and Material ... https://books.google.com/books?isbn=1466570474 Tribikram Kundu - 2016 - Science Planar rectangular -: --> QQD -0 -4 Q o $Q bo : • *-4 * o QD $Q : KOf interest in this study is the response of these two sensor types to flaws of increasing depth. Security and Reliability of Damaged Structures and Defective Materials https://books.google.com/books?isbn=9048127920 Guy Pluvinage, Aleksandar Sedmak - 2009 - Technology & Engineering The dependence of allowable height a on length l for surface planar flaws ... be characterized and if characterized as planar, are rejected.9 ASME Boiler and ... [PDF]Ultrasonic Characterization of Defects and Damage in Thick Composites lib.dr.iastate.edu/cgi/viewcontent.cgi?article=2229&context=qnde by IM Daniel - 1990 - Cited by 4 - Related articles composites. Techniques for characterization of some manufacturing defects in thick ... planar view of the specimen with its defects was obtained. The original ... Nondestructive Testing Standards--present and Future https://books.google.com/books?isbn=0803114877 Harold Berger, Leonard Mordfin - 1992 - Gamma rays Flaw detectability also depends on the relative coarseness of the material's grain structure. ... voids, inclusions, as opposed to two- dimensional or planar flaws like cracks. ... Materials Characterization Methods Fairly large flaws are frequently ...
