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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 22, Issue 6 - Dec 2002
Volume 22, Issue 5 - Oct 2002
Volume 22, Issue 4 - Aug 2002
Volume 22, Issue 3 - Jun 2002
Volume 22, Issue 2 - Apr 2002
Volume 22, Issue 1 - Feb 2002
Selecting the target year
The Real-time Health Monitoring System of a Cable-stayed Bridge Based on Non-destruction Measurement
Choi, Man-Yong ; Kang, Kyung-Koo ; Kim, Jong-Woo ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 239~245
Many civil and infrastructures continue to be used despite aging and the associated potential for damage accumulation. Therefore, the ability to monitor the health of these systems is becoming increasingly important. The purpose of this paper is to propose a real-time health monitoring system of cable-stayed bridge, based-on non-destructive measurement. And also this paper focuses on the safety assessment for bridge from health monitoring system to accomplish this safety assesment. Using the proposed health monitoring system, it helps bridge maintenance and reduces the economic cost of a life-cycle costs. Also it give important data to develop the design and analysis method for cable-stayed bridges.
Development and Application of an Ultrasonic Gas Flowmeter
Hwang, Won-Ho ; Park, Sang-Gug ; Jeong, Hee-Don ; Jhang, Kyung-Young ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 246~253
This paper describes the development and the field application of the ultrasonic gas flowmeter for accurate measurement of the volumetric flow rate of gases in a harsh environmental conditions in iron & steel making company. This ultrasonic flowmeter is especially suited for measuring LDG, COG, BFG gases produced in iron & steel making process. This is a transit time type ultrasonic flowmeter. We have developed the transmitting & receiving algorithm of ultrasonic wave and the ultrasonic signal processing algorithm to develope a transit time type ultrasonic flowmeter. We have evaluated the performance of ultrasonic flowmeter by the calibration system with Venturi type standard flowmeter. We has confirmed its reliability by extensive field tests for a year in POSCO, iron & steel making company. Now we have developed the commercial model of ultrasonic flowmeter and applied to the POSCO gas line.
Development of Mobile Robot Systems for Automatic Diagnosis of Boiler Tubes in Fossil Power Plants and Large Size Pipelines
Park, Sang-Deok ; Jeong, Hee-Don ; Lim, Zhong-Soo ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 254~260
In this study, two types of mobile robotic systems using NDT (Non-destructive testing) method are developed for automatic diagnosis of the boiler tubes and large size pipelines. The developed mobile robots crawl the outer surface of the tubes or pipelines and detect in-pipe defects such as pinholes, cracks and thickness reduction by corrosion and/or erosion using EMAT (Electro-magnetic Acoustic Transducer). Automation of fault detection by means of mobile robotic systems for these large-scale structures helps to prevent significant troubles without danger of human beings under harmful environment.
Automated Technology for Pipelines Inspection Using Inpipe Robot
Roh, Se-Gon ; Choi, Hyouk-Ryeol ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 261~266
Up to now a wide variety of researches on inpipe robots for inspection have been introduced, but it still seems to be difficult to construct a robot providing mobility sufficient to navigate inside the complicated configuration of underground pipelines. The robot for the inspection of pipelines should freely move along the basic configuration of pipelines such as along horizontal or vertical pipelines. Moreover it should be able to travel along reducers and elbows, and especially the capability for steering in branches is essential to it. In this report, citical points and technologies in the development of the inpipe inspection robots are introduced and inpipe robots developed for last several years are introduced.
An Evaluation on Electrochemical Polarization Characteristics and Material Degradation for Cr-Mo-V Steel
Kwon, Il-Hyun ; Lee, Song-In ; Ha, Jeong-Soo ; Yu, Hyo-Sun ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 267~274
This research is described on the applicability of a electrochemical techniques for evaluating nondestructive material degradation with various polarization characteristics for Cr-Mo-V steel. The applied electrochemical technique is anodic polarization test which are widely used to evaluate the corrosion rate and/or sensitization at depleted zone of strengthening elements mainly caused by thermal experience for stainless steels. The evaluation of material degradation is performed by small punch test which has been well known as micromechanics test method using specimen size of
. The 1,000hrs aged material at
shows the highest material degradation
, but the 2,000hrs and 3,000hrs aged materials show the decrease of
as aging time increases. It is observed that the difference of current density
Precise Detection of Buried Underground Utilities by Non-destructive Electromagnetic Survey
Shon, Ho-Woong ; Lee, Seung-Hee ; Lee, Kang-Won ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 275~283
To detect the position and depth of buried underground utilities, method of Ground Penetrating Radar(GPR) survey is the most commonly used. However, the skin-depth of GPR is very shallow, and in the places where subsurface materials are not homogeneous and are compose of clays and/or salts and gravels, GPR method has limitations in application and interpretation. The aim of this study is to overcome these limitations of GPR survey. For this purpose the site where the GPR survey is unsuccessful to detect the underground big pipes is selected, and soil tests were conducted to confirm the reason why GPR method was not applicable. Non-destructive high-frequency electromagnetic (HFEM) survey was newly developed and was applied in the study area to prove the effectiveness of this new technique. The frequency ranges
and the skin depth is about 30m. The HFEM measures the electric field and magnetic field perpendicular to each other to get the impedance from which vertical electric resistivity distribution at the measured point can be deduced. By adopting the capacitive coupled electrodes, it can make the measuring time shorter, and can be applied to the places covered by asphalt an and/or concrete. In addition to the above mentioned advantages, noise due to high-voltage power line is much reduced by stacking the signals. As a result, the HFEM was successful in detecting the buried underground objects. Therefore this method is a promising new technique that can be applied in the lots of fields, such as geotechnical and archaeological surveys.
Evaluation of Microstructure and Ductile-Brittle Transition Temperature in Thermally aged 2.25Cr-1Mo Steel by Electrical Resistivity Measurement
Byeon, Jai-Won ; Kwun, S.I. ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 284~291
An attempt was made to evaluate the degree of aging degradation in thermally aged 2.25Cr-1Mo steel by electrical resistivity measurement. Artificial aging was performed to simulate the microstructural degradation in 2.25Cr-1Mo steel arising from long time exposure at
. Microstructural parameter (amount of solid solution element), mechanical property (ductile-brittle transition temperature) and electrical resistivity were measured to investigate the mutual relationship among these parameters. Depletion of solid solution element(Mo and Cr) in matrix was detected after aging. The ductile-brittle transition temperature(DBTT) increased rapidly in the initial stage of aging and then saturated afterward. On the other hand, the electrical resistivity decreased rapidly in the beginning and then saturated in the later stage of aging.
Estimation of Setting Time and Early-age Strength of Concrete Using the Ultrasonic Pulse Velocity
Lee, Hoi-Keun ; Lee, Kwang-Myong ; Kim, Young-Hwan ; Yim, Hyun-June ;
Journal of the Korean Society for Nondestructive Testing, volume 22, issue 3, 2002, Pages 292~303
This paper presents experimental results for early-age properties of concrete such as the setting time and strength, evaluated via the ultrasonic pulse velocity (UPV). Developing and using an automatically-recording monitoring system, the UPV's of mortar and concrete with various water to binder ratios (W/B) were measured during the first 24 hours. In addition, probe penetration and compression tests were conducted to measure the setting time and compressive strength, respectively. It was observed that the UPV's of mortar with high W/B remained constant during the first 6.5 hours and then abruptly began to increase at constant rates. On the other hand, the UPV of mortar with low W/B increased relatively slowly and gradually due to the setting retardation caused by the use of high range water reducing agent (HRWR). It was found that setting of concrete occurs when the UPV reaches a certain value. Moreover, it was concluded that the estimation formulas should incorporate the effects of W/B to more accurately estimate the early-age strength of concrete from the UPV.