• Proceedings of the KWS Conference
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• 2006.10a
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• pp.277-279
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• 2006

Due to the numerous environmental factors, cracks and corrosion are frequently occured especially in old steel bridge, which deteriorate the structural integrity; thus bring about the problems of structural safety of the steel bridge. Therefore, repair and reinforcement are required for the damaged structure. the replacement repair welding method is spotlighted for its brilliant features, i.e. it can be achieved without incurring traffic dislocation. the method cuts the damaged parts and replaces them with new steel plate by welding under live loads. However, the mechanical behavior of the welded joints under cyclic loads due to the traffic which passes along bridge is not clarified. In this paper, the fatigue strength of the replacement repair welded joints was investigated in order to improve reliability in the repair welded joints of old steel bridge.

• Tribology and Lubricants
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• v.13 no.2
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• pp.82-88
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• 1997

This paper describes an empirical equation which can be used to predict the engine condition of supersonic aircraft. The equation, which is derived from the trend analysis of JOAP data, represents the concentration of Fe particles in the engine oil. The result of the trend analysis shows that the concentration of Fe particles is a function of running time of engine oil. Meanwhile the slope of Fe concentration is a function of running time of engine. Threfore, the empirical equation was derived as $w=a(t_e).t_o+b$. However, the equation could not enough to diagnose the damaged part of engine quantitatively. To make up for the weak points of the equation, qualitative analysis was carried out. For that purpose wear debris were collected from the abnormal engine and analyzed by EDS to detect the damaged parts of engine.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.389-396
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• 2017

Restorations of automotive parts have been done ever since the first vehicle was produced. Because the most expensive parts of a vehicle are in the engine system, there have been various restoration methods developed for engine parts. In the case of commercial diesel engines, the fuel injection device is a key and expensive component. It also has a significant effect on vehicle performance. In particular, reduced engine power and increased exhaust gas emissions may result from mechanical damage due to abrasion of the spill valve in the fuel injection system of a diesel engine. In this paper, restoration techniques for damaged parts are applied to restore the abrasion of a spill valve of fuel injection, also called as the "unit injector", of commercial diesel engines. In order to recover the damage, optimized polishing techniques using hard-metal and coating processes are applied. To evaluate restoration techniques for the spill valve, performance and durability tests are performed on a test bench.

• Journal of the Semiconductor & Display Technology
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• v.22 no.4
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• pp.99-102
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• 2023

In this paper, the system is proposed and implemented to share the part number, the part name, and the vehicle type through the improvement sharing bulletin board for automobile repair and maintenance. And when photos of damage parts are uploaded to the system, the system analyzes it using a deep learning model to analyze whether it is damaged and automatically classify the type of damage. By providing repair and maintenance quotes for a significant part, the system provides economically repaired by providing comparative adjustment information on repair costs to drivers who are particularly concerned about the market prices of parts and maintenance services. Through the existing bulletin board, you can exchange and share information about parts by sharing various information on repair and maintenance. This paper provides in detail the average market price per type of damage during automobile repair and maintenance, helping drivers who do not know the details of parts and maintenance services to receive reasonable quotes by providing price information.

• Fire Science and Engineering
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• v.30 no.4
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• pp.121-127
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• 2016

This study analyzed the structural and electrical characteristics of an iron fittings type Corrugated Stainless Steel Tubing (CSST) damaged by the Primary Current Injection Test System (PCITS). CSST consists of cladding, tube, nuts, clamp ring, flare cap, socket, and ball valve. For an evaluation of the dielectric withstand voltage, the area between the live part and non-live part of the CCST shall withstand a voltage of 220 V AC for one minute. For an evaluation of the insulation performance by 500 V DC, it is required that the insulation exceed more than $1M{\Omega}$ before the temperature rise test, $0.3M{\Omega}$ after the test. Although the average resistance of the product was $11.5m{\Omega}$, that of the product damaged at a current of 130 A by the PCITS was $11.50m{\Omega}$. Furthermore, parts of the cladding were melted and black smoke appeared when a current of 130 A applied for 10 s. After 60 s, most parts were heated and turned red. At 120 s, the parts that turned red had widened. Although it did not form a normal distribution because the P value was 0.019 with a confidential interval of 95%, it revealed outstanding characteristics with an AD (Anderson-Darling) value of 0.896 and a standard deviation of 0.5573.

• Journal of Korean Society of Forest Science
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• v.79 no.4
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• pp.419-423
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• 1990

This study was carried out to investigate the cause of pith-damaged wood formation, the state of growth, and difference of chemical composition of Japanese Larix(L. leptolepis Gorden). 1. Larix grew normaly to 10 years, and the volume increment was 32.4%. But it was gradually decreased to 19.4% from 11 to 13 years that the heartwood damage was occurred. Therefore, the volume increment was decreased 13%. The decayed wood was formed from fire wound portion of bark by forest fire. The volume loss from pith-dagmaged wood occurred by forest fire was more than 20%. 2. On the ash content, heartwood(0.05%) and pith-damaged wood(0.08%) was lower than sapwood(0.29%). The difference of extractive contents are considered the reason. It is considered that this ash content difference is depend upon the extractive contents among sap, heart and decayed wood parts. Holocellulose contents were from 54.3% to 59.3% and there were no difference among heartwood, pith-damaged wood, and sapwood, On the pentosan contents, heartwood(6.3%) and pith-damaged wood(6.6%) were higher than sapwood. Lignin contents of pith-damaged wood was tower than heartwood (34.4%). This seems to weaken all kinds of wood strength.

• 제어로봇시스템학회:학술대회논문집
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• 1997.10a
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• pp.1696-1699
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• 1997

The robot mainpulator for inspection of pressurizer in the nuclear power plant has been developed, which consists of four parts : 2 arms, movable gripper, base frame, contorl console. To extract the damaged electric heating rod inside pressurizer, the gripper has been developed using wire lope and self-locking mechanism. for the examination of the structural stability of the robot manipulator, stress analysis is performed by using the ANSYS code.

• Proceedings of the Korean Society For Composite Materials Conference
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• 2002.05a
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• pp.167-172
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• 2002

During the operation of military aircraft, maintenance is divided into organizational, intermediate and depot maintenance. In the depot maintenance, after removal of major parts and removable doors, damage assessment is performed. Locating damage, charactering the damage and determining its extent, zoning the damage on the part being repaired and re-evaluation of the damaged area after damage removal. Repair joints are classified by bonded joints and bolted joints, depending on joining material. In this paper, repair method in aging aircraft is investigated and the possibility of application of copmposite patch is surveyed.

• Proceedings of the Korean Society of Tribologists and Lubrication Engineers Conference
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• 1996.10a
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• pp.176-182
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• 1996

This paper describes an empherical equation which is to predict the engine condition of the supersonic aircraft. The equation, which is a function of running time of engine and engine oil, is derived from the trend analysis of JOAP data. Qualitative analysis is carried out to make up for the weak points in the current JOAP system. Also wear debris collected from the abnormal engine is analyzed by EDS to detect the damaged parts of engine.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1258-1261
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• 2003

Oil supply system is one of the most important part of Turbine. Lubricating oil of bearings supplied by oil pump. Failure of Oil supply pump critical damaged parts of Turbine, especially bearings. In this paper we have discussed the serious damage of turbine bearings due to failure of Oil supply pump.