Nondestructive ultrasonic

With nondestructive ultrasonic test back and forth scanning of a specimen is accomplished with ultrasonics. This NDT can be used to find voids, delaminations, defects in fiber distribution, etc. In ultrasonic testing the sound waves from a high frequency ultrasonic transducer are beamed into a material. Discontinuities in the material interrupt the sound beam and reflect the energy back to the transducer, providing data that can be used to detect and characterize flaws. It can locate internal flaws or structural discontinuities by the use of high frequency reflection or attenuation (ultrasonic beam). 

Ribbon Test (B.S. 1902 Pt.5.12) The lower faces of a series of bricks are heated by a linear burner 1.52m long at 980°C for 15min. The bricks are then cooled to 200°C. The reduction in modulus of elasticity (using a nondestructive ultrasonic method) after 5-10 cycles provides a measure of themal shock resistance. ASTM Cl 100 also specifies a ribbon test. 

Chan,R.W.Y., Hay,D.R., Matthews,J.R., MacDonald,H.A., (1988), Automated Ultrasonic System for Submarine Pressure Hull Inspection , Signal Processing and Pattern Recognition in Nondestructive Evaluation of Materials, C.H.Chen (ed). Springer-Verlag, pp. 175-187... 

The ultrasonic testing of anisotropic austenitic steel welds is a commonly used method in nondestructive testing. Nevertheless, it is often a problem to analyze the received signals in a satisfactory way. Computer simulation of ultrasonics has turned out to be a very helpful tool to gather information and to improve the physical understanding of complicated wave phenomena inside the samples. 

Chapman, R.K., "A system model for the ultrasonic inspection of smooth planar cracks", J. Nondestruct. Eval., 1990,9, 197-211. 

Nondestructive testing techniques for welded joints usually include visual, radiographic, magnetic particle, liquid penetrant, and ultrasonic testing methods. Of interest in this paper is the radiographic testing (RT) technique. 

There have been numerous efforts to inspect specimens by ultrasonic reflectivity (or pulse-echo) measurements. In these inspections ultrasonic reflectivity is often used to observe changes in the acoustical impedance, and from this observation to localize defects in the specimen. However, the term defect is related to any discontinuity within the specimen and, consequently, more information is needed than only ultrasonic reflectivity to define the discontinuity as a defect. This information may be provided by three-dimensional ultrasonic reflection tomography and a priori knowledge about the specimen (e.g., the specimen fabrication process, its design, the intended purpose and the material). A more comprehensive review of defect characterization and related nondestructive evaluation (NDE) methods is provided elsewhere [1]. 

Gutkiewicz P. "Ultrasonic and eddy current nondestructive testing in Windows envirorunent , ZfP als Dienstleitung in einer veranderten Industriestruktur, Dresden, 5-7 Mai 1997, P 67... 

R. Coulette, E. Lafond, F. Lepoutre, D. Balageas, M.-H. Nadal and C. Gondard, Laser ultrasonics NDE of two-layered samples . Review of Progress in Quantitative Nondestructive Evaluation, Vol 17, edsD. O. Thompson and D. E. Chimenti (Plenum, New York, 1998), to be published. 

G. Passi und S. Passi MUTOS Equipment for increasing reliability of ultrasonic weld inspection. International Conference Advanced Technologies in Welding and nondestructive examination. Proc., Tel-Aviv, 1993, p 32-34... 

The first full text NDT Journal on www.ndt.net, the Online Journal of Nondestructive Testing Ultrasonics, is on the Internet and each month provides new information as well as a comprehensive overall reference - access is free since it is sponsored by the NDT online exhibition. 

Rocket propellants must not contain sizable cracks, pores, or cavities. They are inspected using x-rays and ultrasonics, and firings are conducted in strand burners, intermpted burners, and in reduced or full-scale rocket motors (see also Nondestructive evaluation) (16—20). 

Nondestructive Testing. Nondestmctive inspection of an explosion-welded composite is almost totally restricted to ultrasonic and visual inspection. Radiographic inspection is appHcable only to special types of composites consisting of two metals having a significant mismatch in density and a large wave pattern in the bond interface (see Nondestructive evaluation). 

P. Mclntire, ed., "Ultrasonic Testing," Nondestructive Testing Handbook, Vol. 7, 2nd ed.. The American Society for Nondestmctive Testing, Columbus, Ohio, 1991. 

Stress-corrosion cracks tend to be fine, tight, and easily overlooked. Various nondestructive techniques are available to aid in the discovery of cracks, such as dye penetrant, and ultrasonic and radiographic techniques. 

Corrosion-fatigue cracks can be detected by nondestructive testing techniques such as magnetic particle inspection, radiography, ultrasonics, and dye penetrant. Corrosion-fatigue cracks may occur in numerous tubes simultaneously. Nondestructive testing of tubes at locations similar to those in which cracks are observed can be useftil. 

Among the available nondestructive testing techniques are ultrasonic tests, eddy-current tests, air-underwater and hydrostatic tests, and visual examinations. All of these techniques must be executed by technically qualified personnel. 

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