Papers by Keyword: Eddy Current Test

Abstract: Eddy current testing method has a wide usage in the field of Industry. Especially, aircraft maintenance field has so many applicable areas for this method. In addition, a wide variety of inspections and measurements may be performed easily with the eddy current method. More effective and flexible operation conditions were reached by designing wireless eddy current probe prototype for all aircraft maintenance inspections. Prototype probe design, the advantages of use of this probe in aircraft maintenance applications and inspections performed as wireless were studied in this paper.

Abstract: An investigation was conducted to explore the applicability of eddy current nondestructive evaluation technique for the characterization of manganese steels. Specimens of two different types of manganese steels were subjected to various compression loads. The specimens were then evaluated by mechanical and eddy current testing. The hardness and eddy current values were increased due to conversion of austenite to martensite. In this study the correlation between eddy current parameters and compression load was discussed.

Abstract: High Speed Brushes Aeration Mechanics are the effective aeration equipments which are widely used in the environmental protection. Because of the big span of main spindle and its high speed when it is working, the breakdown sometimes occurs. It is very importance to monitor its condition and diagnose its breakdowns. Turbulent Flow Displacement Sensors are the non-contact types which are based on eddy current effect. It has many advantages, such as good linearity, wide frequency response scope, convenience installment and so on. So it is very suitable for the main spindle’s vibration signals of a high speed brushes aeration mechanic are monitored. With the development of Artificial Neural Networks technology, the equipment breakdown diagnosis has realized intellectualization. The recognition of equipment failure types is one of the most important studying domains of Artificial Neural Networks at present. Based on the research of eddy current effect and Artificial Neural Networks, we build up a test system which can monitor condition and diagnose breakdown to a GSB-12 high speed brushes aeration mechanic. With the help of it, the vibration signals of the measurement points on the main spindle are measured at two mutually vertical positions. The signals’ base frequency and multiplicative frequency are taken as characteristic value. Six common breakdowns are selected and to be taken as the standard sample and there are 3 lays in the neural network. Using FBP algorithm, we get a satisfied effect. The experiment has confirmed that this method is advanced, reliable and practical. It provides a new method about intelligent monitor and breakdown diagnosis to high speed brushes aeration mechanics’ condition.

Abstract: Steam generators(SG) of the Korean nuclear power plants were replaced with a new one after a 20 year operation. A metallographic examination of the defected tubes is needed for setting up a guide line for a safe operation of the other SG. A destructive analysis of 50 tubes was addressed, and a relationship between the SCC defect location and defect depth was obtained. Tubes extracted from the retired SG were transferred to a hot laboratory. Detailed nondestructive analysis examinations were taken, then the tubes were destructively examined. Types and sizes of the defects were characterized. A location and depth of the SCC were evaluated in terms of the location and height of the sludge. Most axial cracks were in the sludge pile, whereas the circumferential ones were around the top of the tube sheet(TTS) or below the TTS. Cracks were found with various lengths in a specific zone. Average defect depth of the axial cracks was deeper than that of the circumferential ones.

Abstract: The Korea Electric Power Research Institute (KEPRI) has developed performance demonstration programs for non-destructive testing personnel who analyze ECT (eddy current testing) data for steam generator tubing since 2001. The purpose of these performance demonstration programs is to ensure a uniform knowledge and skill level of data analysts and contribute to safe operation of nuclear power plants. Many changes have occurred in non-destructive testing of steam generator tubing such as inspection scope, plugging criteria and qualification requirements in Korea. According to the Notice 2004-13 revised by the Ministry of Science and Technology (MOST), the analyst for steam generator tubing shall be qualified as the qualified data analyst (QDA), and the site specific performance demonstration (SSPD) program shall be implemented. KEPRI developed these performance demonstration programs and they are being successfully implemented. The analyst's performance is expected to be improved by the implementation of these programs.