Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of the Korean Society for Nondestructive Testing
Journal Basic Information
Journal DOI :
The Korean Society for Nondestructive Testing
Editor in Chief :
Volume & Issues
Volume 18, Issue 6 - Dec 1998
Volume 18, Issue 5 - Oct 1998
Volume 18, Issue 4 - Aug 1998
Volume 18, Issue 3 - Jun 1998
Volume 18, Issue 2 - Apr 1998
Volume 18, Issue 1 - Feb 1998
Selecting the target year
Effects of Wave Attenuation on the Acoustic Emission Amplitude Distribution of Injection-Molded Fiber/Plastic Composites
Choi, N.S. ; Takahashi, Kiyoshi ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 1~9
The attenuation of acoustic emission (AE) waves was evaluated for injection-molded short-fiber-reinforced thermoplastic composites employing simulated AE waves. Values of attenuation coefficient (
) decreased more with increasing fiber volume fraction (
) than that expected from a simple linear relation between
. The effect of wave attenuation was taken into account in a quantitative analysis of the AE peak amplitude distribution which was obtained from each zone partitioned in a specimen gage portion. The amplitude distribution compensated for the measured attenuation loss was exhibited almost similar in every zone of the specimen. Consequently, it was, shown that the AE amplitudes obtained from fiber/plastic composites were considerably affected by the attenuation.
Evaluation of Toughness Degradation of 1Cr-1Mo-0.25V Steel by Electrical Resistivity
Nahm, S.H. ; Yu, K.M. ; Kim, A. ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 10~16
Remaining life of turbine rotors with a crack can be assessed by the fracture toughness of the aged rotors at service temperature. DC potential drop measurement system was constructed in order to evaluate material toughness nondestructively. Test material was 1Cr-1Mo-0.25V steel used widely for turbine rotor material. Seven kinds of specimen with different degradation levels were prepared according to isothermal aging heat treatment at
. Electrical resistivity of test material was measured at room temperature. It was observed that material toughness and electrical resistivity decreased with the increase of degradation. The relationship between fracture toughness and electrical resistivity was investigated. Fracture toughness of a test material may be determined nondestructively by electrical resistivity.
Classification of Defects in Rotary Compressor by Neural Pattern Recognition of Acoustic Emission Signal
Lee, K.Y. ; Lee, C.M. ; Hwang, I.B. ; Kim, Y.W. ; Hong, J.K. ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 17~26
The specimen with the wear between a roller and a vane and a normal specimen are classified by AE signal pattern recognition method with a neural network classifier in airconditioning operation test. Also the specimen with the scoring between a shaft and a bearing and a normal specimen are classified by the same method. As the internal pressure increases, the wear between the roller and the vane increases. The different pairs of oils and refrigerants five the effect on the wear.
An Intelligent Tutoring System for Nondestructive Testing Training
Kim, J.K. ; Koh, S.N. ; Kim, M.K. ; Shim, Y.J. ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 27~32
This paper is written to introduce a multimedia tutoring system for nondestructive testing using personal computer. Nondestructive testing, one of the chief methods for inspecting welds and many other components, is very difficult for the NDT inspectors to understand its technical basis without a wide experience. And it is necessary for considerable repeated education and training for keeping their knowledge. The tutoring system that can simulate NDT works is suggested to solve the above problem based on reasonable condition. The tutoring system shows basic theories of nondestructive testing in a book-style with video images and hyper-links, and it offers practices, in which users can simulate the testing equipment. The book-style and simulation practices provide effective and individual environments for learning nondestructive testing.
Response Characteristics of the PZT Transducers during Glass Capillary Breakage
Lee, Jong-Kyu ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 33~41
The response characteristics of the PZT transducers during glass capillary breakage were studied at the epicenter of the glass plate. The PZT transducers had been made by using EC-65 PZT ceramics(supplied by Edo co.) with a constant area and a various thickness. The theoretical displacement and velocity at the epicenter of glass plate with an air boundary condition were calculated by assuming the point load of 1N force strength and a rise time of 280 ns with a ramped functional dependence, and the 1st pulses of the PZT transducer may be considered as the vertical velocity incident on the electrode of the PZT ceramic. The responses of the PZT transducer may be depended on the thickness mode of the PZT ceramic below 0.33 in the ratio of the thickness to the diameter of PZT ceramic, but the reponse of the PZT transducer may be depended on the other modes of PZT transducer in the addition of the thickness mode of the PZT ceramic above 0.33. The full time of half maximum at the 1st pulse was nearly 280 ns without a variation of applied breakage load and the resonant frequency of the PZT transducer, and then may be considered as the rise time of a AE source. The maximum amplitude of the 1st pulse depended on the incident vertical velocity and capacitance of the PZT transducer. Therefore, the full time of half maximum and maximum amplitude of the 1st pulse may be considered as the rise time and strength of acoustic emission source respectively.
Automated Ultrasonic Testing of Offshore Structure
Jyung, D.H. ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 42~45
The Role of FENDT - Prospect and Retrospect -
Lee, Hae ;
Journal of the Korean Society for Nondestructive Testing, volume 18, issue 1, 1998, Pages 46~49
Being latecomers to the industrialization, Pacific rim countries except the U.S.A. are doing very little in developing the universal certification system. One should note that Asian Pacific region enjoys the highest economic growth rate, and there is a good possibility that it will be the center of economic activities of the world in the next century. It appears that ISO and CEN share similar specifications in numerous areas. ASNT is being changed to cope with the trend with the introduction of ACCP. Although we may have to adopt the new system someday, we should pay attention and make concerted effort to include our own practice in the global standards. We are the countries in the Far East Region with similar culture and tradition, which are quite different from those of western countries. We hope that Japan should play an important role in this matter, who has been chaired the ISO TC135 since 1993. In the beginning of this decade, there has been a trivial but troublesome matter that who is representing the NDT Society or member countries in Asia-Pacific Conference on NDT. The problem appears to be solved since the establishment of FENDT For the next decade, actually next centry, FENDT will have to accomplish another important role for countries in the Far East Region to form a strong coalition for its survival in the western dominant world. Immediate issue is to establish Far East Working Group for Harmonization and Mutual Recognition of Qualification and Certification of NDT Personnel. To realize this Japan must play a leading role with the cooperation of expanded FENDT member countries including China and Russia. As the continued prosperity expected in this region, FENDT should continue its role for the next centry. We, the FENDT countries, must move forward for internationalization(國際化). However' we must realize that it all start from SELF IDENTI-FICATION. We can identify ourselves by actively participating in FENDT. I would like remind you the concluding remark that I have made in the congratulatory speech at JSNDI 40th Anniversary Conference and FENDT'92. JSNDI is too precious to be Japan's sole possession Staling from the Far East, JSNDI shall become one of the loaders of the world. I sincerely hope that JSNDI take initiatives and leaderships in the future activities. of FENDT countries. I would like to close my talk with "We must hang together, or We shall be hang seperately." Garn Sa Ham Ni Da.