• International Journal of Railway
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• 제5권1호
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• pp.22-28
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• 2012

This report is devoted to the problems of Mongolian Railway Transportation Safety such as high length of wagon service life, defects due to the more factors of exploitation, idle time, increase of faults, poor condition of repairing shops and more hand and mechanical operations and these conditions are quite difficult to meet the safety and reliability of increasing transportation from day to day. The paper discusses that the most optimum solution is diagnosing before occurring wear, breakdown, and defects on the basis of studying characteristics of structural material breakdown, residual methods of voltage, effects of material hardness and linear defects of a crystal net and the reform of machines is very important to implement it. It focuses the structures, characteristics of the material transportation and tests and analyses of the wagon cart which has to meet the traffic safety of wagons and slow and soft movement. The study is done on the wagon chassis which has to meet the traffic safety of luggage wagons.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 봄 학술발표회 논문집
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• pp.470-475
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• 2000

This research covers the resting of precast/prestressed concrete I-Girder bridge. The research was designed to examine processes for improving the condition evaluation and rating of prestressed concrete bridge. To establish procedures that allow for the full utilization of prestressed concrete bridge capacity, a 28-year old sample was loaded to failure in site. The bridge was constructed with 12 spans, and girders of each span were simply supported. At each loading stage, the deflections, reinforcement strains, prestressing wire strains and concrete strains were examined. Failure behavior was analyzed, and failure load was also evaluated. The test results wee compared to the analytical results from the non-linear finite element analysis.

• International Journal of Safety
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• 제7권1호
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• pp.10-14
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• 2008

For evaluating the radiation degradation of cross-linked polyethylene (XLPE) cable insulation due to the irradiated oxidation, XLPE was irradiated with ${\gamma}$-ray. For each irradiated samples, TGA, DSC, FT-IR, and tensile tests were carried out. Regarding radiation degradation, oxidative process was predominant. TGA, DSC and FT-IR can be useful tools for evaluating the radiation degradation due to the irradiated oxidation because these analyses need only small amount of samples. The results of TGA, DSC and FTIR analyses showed the similar tendency for irradiated degradation. They can be useful tools for evaluating the oxidation of insulating material by non-destructive testing.

• Advances in Computational Design
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• 제2권3호
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• pp.143-163
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• 2017

This paper presents a non-destructive testing method for estimating the structural response of cable-stayed footbridges. The approach combines field measurements with a numerical static analysis of the structure. When the experimental information concerning the structure deformations is coupled with the numerical data on the structural response, it is possible to calculate the static forces and the design tension resistance in selected structural elements, and as a result, assess the condition of the entire structure. The paper discusses the method assumptions and provides an example of the use of the procedure to assess the load-carrying capacity of a real steel footbridge. The proposed method can be employed to assess cable-stayed structures including those made of other materials, e.g., concrete, timber or composites.

• 한국터널지하공간학회 논문집
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• 제6권2호
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• pp.151-160
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• 2004

본 연구는 국내 재래식 철도 터널에서 발생한 아치부 종방향 균열 부위에 대하여 각종 현장조사를 실시하여 터널의 변상상태를 파악한 것이다. 현장 외관조사 및 각종 비파괴 조사를 통하여 균열 부위에 대한 상세한 조사를 실시하였으며 현장조사 결과를 토대로 균열의 발생 원인을 추정하였다. 아울러 현장여건을 고려한 안전성 해석을 실시하여 터널 구조물의 균열 발생 가능성을 검토하였다.

• 대한기계학회논문집A
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• 제20권1호
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• pp.68-78
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• 1996

A study of the natural vibraion of Timoshenko beam with a laminar tear is presented. An analytic model, based on the transverse and longitudinal vibration of beams is employed to determine the natural frequencies. A specific example are given to show the effects of rotary inertia, and shear deformation on the natural frequencies of the beam with a laminar tear. the variations of matural frequencies of beam with the changes of size and location of laminar tear are plotted for several thickness ratio.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 1995년도 춘계학술대회 논문집
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• pp.308-313
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• 1995

Non-destructive inspection techniques using laser have been broading their application areas as well as growing their measurement skills together with the rapid development of circumferential technology like fiber optics and computer. The remarkable inspection technique using laser speckle, so-called ESPI is aleady on the stage of on-line testing with commercial products in other nations. Especially, this technique is expected to be applied to the nuclear industry. Because it is proper for the vibration measurement and it can be applied to objects of a high temperature. This paper describes the use of the ESPI system for measuring vibration patterns on the reflecting objects. Using this system, high-quality Jo fringers fso that fringe shift algorthms can be used to determine vibration interferograms recorded by the ESPI system.

• 한국정밀공학회지
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• 제18권5호
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• pp.34-41
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• 2001

More accurate and fast inspection method for mechanical parts and structure is required to guarantee the safety. Conventional methods using compliance method, eddy current method, ultrasonic wave, acoustic emission for non-destructive testing in mechanical parts and structure have been performed as the method of contact with objects to be inspected. With this reason these methods have been taken relatively much time, money, and manpower. In this study, in order to overcome these shortcomings, we used In-plane Electronic Speckle pattern Interferometry(In-plane ESPI) that was full-field measurement and noncontact method. We detected the cracks of the specimen at a real time and measured the length of the crack by using In-place ESPI system. Finally, we compared this results with conventional microscope method.

• International Journal of Automotive Technology
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• 제2권2호
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• pp.47-52
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• 2001

For the wear protection of cylinder bore in aluminum cast material the internal plasma spraying technology offers a new economical solution. The size and the weight of the engine blocks significantly can be decreased in comparison with the traditional cast iron sleeves. The coefficient of friction between piston ring and cylinder wall sensitively can be reduced and the wear resistance increased from several factors. The paper gives an overview of the technology from the AlSi cast alloys for engine block to the non destructive testing technology used after the machining by diamond honing. The actual results in engines of different types also will be shown. The economical advantages of the plasma spraying (or the internal coating in cylinder bore also will be discussed in comparison with the different alternatives of technology. The aspect of the market introduction also will be discussed in this paper.

• International Journal of Reliability and Applications
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• 제5권1호
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• pp.15-24
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• 2004

Folder type electronic devices have hinge to support the rotational motion of folder. This hinge is stressed by the rotational inertia moment of folder at the maximum open limit position of folder. This stress is repeated whenever the folder is open, and it is a cause of hinge fracture. In this paper, the reliability evaluation for the hinge fracture in the folder type cellular phone is discussed. For this, the durability testing machine using crank-rocker mechanism is developed to evaluate the life cycle of the hinge, and the degradation after repetitions of opening and shutting is evaluated from the deformation around the hinge, where the deformation is measured by ESPI (electronic speckle pattern interferometer). Experimental results showed that ESPI was able to measure the deformation of hinge precisely, so we could monitor the change of deformation around the hinge as the repetition number of folder open is increased.