• Proceedings of the KSR Conference
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• 2011.10a
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• pp.2691-2696
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• 2011

THE CARBODY AND BOGIE FRAME OF AN URBAN RAILWAY VEHICLE CONSIST OF MULTI-LAYERED WELDING STRUCTURE. IN KOREA ENDURANCE LIMIT OF AN URBAN RAILWAY VEHICLE IS STSTED IN THE RULE OF MANAGING URBAN RAILWAY VEHICLE UNDER THE LAW OF URBAN RAILWAY. IN KOREA AN URBAN RAILWAY VEHICLE IS DESIGNED AND MADE TO KEEP ITS QUALITY OVER 25 YEARS. WHEN THE RAILWAY VEHICLE BECOMES 25 YEARS OLD, CORROSION OF CARBODY AND UNDER FRAME OF A RAILWAY VEHICLE IS EVALUATED ACCORDING TO THE NON-DESTRUCTIVE TESTING. IT CAN BE USED AS LONG AS 40 YEARS. IT IS STATED IN THE ARTICLE 4 'THE METHOD AND STANDARDS OF PRECISE DIAGNOSIS' UNDER THE RULE OF MANAGING RAILWAY VEHICLE IN KOREA. SO, IN THIS STUDY, WE HAVE INVESTIGATED PERFORMANCE OF PULSED EDDY CURRENT TESTING METHOD BY MEASURING THICKNESS VARIATION OF FABRICATE OF CARBODY AND UNDER FRAME FOR URBAN RAILROAD CAR. AND THEM, THE PROCESS OF EVALUATING REMAINING LIFE ACCORDING TO TESTING OF CORROSION AMOUNT IS INTRODUCED.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2002.05a
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• pp.259-262
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• 2002

This paper provides the experimental verification of a non-destructive time domain approach to examine structural damage. Time histories of the vibration response of structure were used to identify the presence of damage. Damage in a structure cause changes in the physical coefficients of mass density, elastic modulus and damping coefficient. This paper examines the use of beam like structures with PVDF sensor and PZT actuator to perform identification of those physical parameters, and hence to detect the damage. Experimental results are presented from tests on cantilevered composite beams damaged at different location and with damage of different dimensions. It is demonstrated that the method can sense the presence of damage, and characterize the damage to a satisfactory precision.

• Corrosion Science and Technology
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• v.11 no.5
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• pp.179-183
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• 2012

As one of promising solutions to overcome high oil price and energy crisis, the construction market of high value-added LNG plants is spotlighted world widely. The purpose of this study is to introduce LNG-RBI system to develop risk assessment technology with RAM(Reliability, Availability, Maintainability) modules against overseas monopolization. After analyzing relevant specific features and their technical levels, risk assessment program, non-destructive reliability evaluation strategy and safety criteria unification class are derived as core technologies. These IT-based convergence technologies can be used for enhancement of LNG plant efficiency, in which the modular parts are related to a system with artificial optimized algorithms as well as diverse databases of facility inspection and diagnosis fields.

• 한국지구물리탐사학회:학술대회논문집
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• 2003.11a
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• pp.464-469
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• 2003

The traditional and still most widely used, test methods for concrete structures are destructive method, such as coring, drilling or otherwise removing part of the structure to permit visual inspection of the interior. While these methods are highly reliable, they are also time consuming and expensive, and the defects they leave behind often become focal point for deterioration. In this study, tomography by theoretical inversion method in case of elastic wave using impact-echo method among concrete non-destruction test method was made. Taken model experiments are theoretical inversion method and time domain and frequency domain test on pier test model at laboratory level. Also experiment concerning frequency domain on 3 kinds of tunnel model with I-dimension form was carried out.

• Proceedings of the KWS Conference
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• 2004.05a
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• pp.327-329
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• 2004

Reliability evaluation of the welded structure for industrial structures/facilities such as power plant and petro-chemical refinery facilities is very important, and especially the reliability diagnosis of the structure is based on the exact evaluation of materials properties. But, the conventional Pre-Qualification test had the difficulty of evaluating the real material properties in the field because the test was made on the specimen with the simulated welding for the in-field welding condition. Therefore, a continuous indentation technique was proposed for simple and non-destructive testing of in-field structures and for selective testing of local range such as heat affected zone and weldment.

• 한국지구물리탐사학회:학술대회논문집
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• 1999.08a
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• pp.65-91
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• 1999

More than 6 years passed until GPR was introduced to our country. GPR method is now widely used in construction site because of its various applicability, convenient handling and low cost. We discussed the characteristics and limits of GPR method with various case study.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.60 no.7
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• pp.1410-1416
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• 2011

A corrosion detecting system for 22.9 kV distribution power line insulation cable, which can travel autonomously along the live line, is proposed. Eddy current test method is employed to detect the corrosion, and the system developed here is capable of detecting internal corrosion of a ACSR-OC. Somewhat details of the electrical and mechanical mechanism of the system and traveling algorithm are introduced. Experimental results applied to the sample cables having artificial corrosion and the operating distribution lines are provided. From the result, we confirmed that the system is useful for detecting internal corrosion of a ACSR, and is expected to be a new non-destructive testing equipment in the area of diagnosis for the distribution power line.

• Journal of the Korean Society for Nondestructive Testing
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• v.36 no.4
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• pp.300-307
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• 2016

The faults in railway vehicle components may result in either the stoppage of the service and the derailment of the vehicle. Therefore, it is important to diagnose and monitor the main components of a railway vehicle. The use of temperature is one of the basic methods for the diagnosis of abnormal conditions in the rotational components of a railway vehicle, such as bearings, reduction gears, brake discs, wheels and traction motors. In the present study, the diagnose of the rotational components using infrared thermography and a pattern recognition technique was carried out and a field test was performed. The results show that this method of diagnosis using infrared thermography can be used to identify abnormal conditions in rotational components of a railway vehicle.

• Journal of the Korean Geophysical Society
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• v.6 no.2
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• pp.71-77
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• 2003

Generally the dynamic characteristics of stone wall structures depend on several factors such as contact, the type of interlocking bonding stones, and the filling materials. This paper describes a non-destructive technique for diagnosis of historic masonry stone structures using the measurement of natural frequency technique. For this purpose, the castle wall of Nag-An Folk Town located in Sunchon, Korea was selected as a model. The Nag-An Town Castle is one of the well maintained historical remains constructed in the Chosun Kingdom of Korea. The construction started in 1397 A.D and was finished in 1626 A.D. The non-mortar castle wall is 1470m long and the average height is 4m with a width of 3 4m. The exterior of the wall is bonded with 1 2 m rectangular rough-faced stone and the inside of the wall is filled with gravel. The traditional village still remains inside the Nag-An Town Castle, and they have a regional food festival every October. Transverse vibrations were measured at 8 points around the castle. The measured natural frequency of the first mode was 26Hz 41Hz, and the shear modulus of filling material was 2.142 x $10^3$ ~ 8.915 x $10^3$kgf/$cm^2$ . With these results, it may be assumed that the filling material is gravel or a sand-gravel mixture. It is expected that the information provided by this paper will be useful for addressing the maintenance problems of the old castle walls.

• Journal of the Korean Society for Nondestructive Testing
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• v.30 no.2
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• pp.121-125
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• 2010

The infrared thermography technology rather than traditional nondestructive methods has benefits with non-contact and non-destructive testings in measuring for the fault diagnosis of the rotating machine. In this work, condition monitoring measurements using this advantage of thermography were proposed. From this study, the novel approach for the damage detection of a rotating machine was conducted based on the spectrum analysis. As results, by adopting the ball bearing used in the rotating machine applied extensively, an spectrum analysis with thermal imaging experiment was performed. Also, as analysing the temperature characteristics obtained from the infrared thermography for in-situ rotating ball bearing under the lubrication condition, it was concluded that infrared thermography for condition monitoring in the rotating machine at real time could be utilized in many industrial fields.