AID T Abstracts

Assessment (AEDA) and a ttwe~-step procedure for AEDA for metal vessels is suggested. Two applications of AEDA carried out in the authors' laboratory are described. The theory and applications show that AEDA has some unique advantages compared to Fracture Mechanics Defect Assessment (FMDA). The disadvantages of AEDA are also discussed.

41740 Waschkies, E.; Gries, H.; Deuster, G.; Hoeller, P. Fundamen ta l s , advanced concepts of measu remen t and equipment, and resul ts of acoustic emission test ing (In G e r m a n : English Abstract) Kernenergie, Vol. 32, No. 3, pp. 89-96 (1989)

The use of acoustic emission testing is discussed as a nondestructive method of materials testing for monitoring and testing loaded components. The state of knowledge about the fundamentals of acoustic emission testing is presented. The interpolation rules for characterizing and distinguishing crack growth and crack border friction are given. The requirements on an advanced testing technique resulting from the state of knowledge presented are discussed, and an appropriate testing system developed at the Institute of Non- Destructive Testing is presented. Finally, the experience gained in the use of acoustic emission testing at pressure vessels during thermal shock and hydraulic pressure tests in the last years is reported. The main results are briefly presented, discussed, and compared to fracture-mechanics calculations.

41737 Waschkies, E.; Gries, H.; Deuster, G.; Hoeller, P. Inves t igat ion of the effect of reactor irradiation on mechanical s t r eng th proper t i es and acoustic emission of WWER-type pressure vessel steels (In G e r m a n : English Abst rac t ) Kernenergie, Vol. 32, No. 3, pp. 89-132 (1989)

A method of determining characteristics of toughness and acoustic emission of irradiated material samples of WWER-type reactor pressure vessels is described. Mechanical strength properties and acoustic emission signal parameters are discussed as a function of temperature.

41538 Hoa, S.V.; Li, L. Acoustic emission d u r i n g quasi-s ta t ic loading/hold/unloading in no tched re inforced f ibre composite materials Journal of Acoustic Emission, Vol. 7, No. 4, pp. 145-160 (Oct.-Dec. 1988)

Acoustic emission (AE) has been extensively used as a quality control technique for many products of reinforced fiber composite materials, such as pressure vessels and storage tanks. The load/hold/unload/reload test schedule is meant to detect any growing damage even when the load is not increasing. The main objective of this work was to study AE char~teristics for reinforced plastic (RP) composite materials with two types of notch and to establish a relation between AE parameters and the danmge in composite materials following a similar loading schedule. Samples with a single-edge notch or a center notch were incrementally loaded in steps of 10% of tensile failure load on each cycle. Crack appearance was continuously recorded with a video camera. The Kaiser effect and Felicity ratios, amplitude distribution, location distribution, cumulative AE counts with loading change were recorded. The relation between AE parameters and applied stress was found. These AE parameters are correlated to damage severity in composite materials.

41339 Waschkies, E. Software development for the reconstruction of source parameters by means of the R and D array. Final repor t Frauhnofer-lnst. fuer Zerstoerungsfreie Pruefverfahren, Saarbruecken (Germany, F.R.), DE88753232/GAR, FhG-IzfP- 840445-TW, 19 pp. (5 Mar. 1986)

The reconstruction of signal parameters at the source (source parameters) is a main problem for the interpretation (classification) of acoustic emission sources. The problem is analyzed here for the less complicated case of linear location. The report explains the efficiency of the programs developed for linear location, transfer corrections, and interpretation of the acoustic emission signals by means of real acoustic emission signals recorded during thermal shock experiments on a reactor pressure vessel nozzle. In this case, classification and separation of acoustic emission signals of the type 'crack growth' and 'crack border friction' is feasible.

41329 Yukuan, Ma; Cheng Xinhong. The 36 channels acoustic emission source location and analysis system and the initial application Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 1602-1604. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

This paper describes the hardware and software of the 36 Channels Emission Source Location and Analysis System. Because defects occur with random quality in time and space, the located defects are expressed with groups. It is used for diagnostics and the evaluation of the large size pressure vessel. The paper also presents acoustic emission detection for spherical vessel containing liquid-hydrocarbon, energy storage tanks for hydraulic press and forging press equipment. To evaluate the integrity of structures the defects' positions and unsteadiness must be ascertained. Defects occur with random quality in time and space. If the defect occurs, there will be acoustic emission signals sent out continuously near the defect position and direction. An area of the acoustic emission source group is defined as a subset to describe the dynamic process of the defects' occuring and extending in time and space. The defects' dynamic actions can be described

. in the acoustic emission parameters of the subset.

4 ! 141 Pellionisz, P.; Szuecs, P.; Trampus, P. Acoustic emission test of WWER-440 pressure vessel Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vot. 2, pp. 1134-1136. Edited by J. Boogaard and G.M, van Dijk, Elsevier, 1989.

The lust periodic inservice inspection of the reactor pressure vessel in Paks Hungary was carried out in 1988, after the fourth year of its operation. The inservice inspection included the NDT-testing of the reactor pressure vessel and a subsequent strength hydraulic test at 191 bar. The temperature for the hydraulic testing was set at 110 deg C on the basis of the surveillance test results. The hydraulic test was carded out during the re-start of the unit with the reactor completely assembled and the core fuelled. In order to obtain additional information during the hydraulic test, an acoustic emission test and a strain gauge measurement were performed. These results, together with the results of the ultrasonic test, have contributed to the overall assessment of the fracture safety of the reactor pressure vessel.

41139 Liu, S.; Wan, Y.; Shen, G.; Duan, Q. Acoustic emission defect assessment for pressure vessels Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 965-967. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

The defect assessment technique is used to evaluate weld defects according to the concept of fitness-for-purpose. The acoustic emission technique has some unique properties as a defect assessment tool for metal vessels. This paper discusses the theory of Acoustic Emission Defect Assessment (AEDA) and a three-step procedure of AEDA for metal vessels is suggested. Two applications of AEDA carried out in the authors' laboratory are describexl.

41138 Prasad, R. Acoustic emission - its industrial applications Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 927-929. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

The paper describes the use of continuous monitoring of Acoustic Emission (AE) Signals for the study of events like phase transformation, stress corrosion, cracking of brittle surface coating, welding processes, tool wear, Cr-plating, leak detection, integrity of reactor pressure vessels, and off-shore structures, in-flight monitoring of air-craft structures, slope stability, onset of rock-fall and determination of fatigue life.

41137 Tscheliesnig, P.; Theiretzbacher, H. New results from the detection of micro- leakages in the petrochemical indus t ry Proceedings of the 12th World Conference on Non-Destructive Testing, Amsterdam (Netherlands), 23-28 Apr. 1989, Vol. 2, pp. 905-911. Edited by J. Boogaard and G.M. van Dijk, Elsevier, 1989.

Conventional and the normal acoustic emission (AE) method will be discussed for the periodic inspection of flat bottomed storage tanks for inflammable hydrocarbon liquids. Because the leaks of storage tanks generate two types of signals it is necessary to vary the filling height in the tank and perform the test at two different levels. By the application of the correlation technique the time lag between two channels follows. Therefore it is possible to find out all steady state type leaks on only one high level test of the filling height. Using both hardware and software systems (the burst detection and correlation system) assurance of one-hundred percent detection of tank bottom leaks can he provided without varying the filling height, which offers a big advantage over the normal AE.

320 NDT&E International Volume 26 Number 6 1993