• Proceedings of the KSR Conference
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• 2004.10a
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• pp.510-515
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• 2004

In this study, we investigate the mechanical properties of rail pad material according to pad types. Especially, to study the application and endurance of TEEE material, we conducted experiments such as tension strength test, hardness test, fatigue test and wear test. Test results showed that TEEE material was better application and endurance than other pad material, but there was difficulties for comparing with others because the variations of application according to pad' types were variable.

• Journal of Welding and Joining
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• v.21 no.1
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• pp.99-106
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• 2003

This research was aimed to evaluate the material degradation with various microstructures of X20CrMoV121 steel weldment by Advanced Small Punch(ASP) test. Due to the regional limitation on constitutive structures, the minimized loading ball(${\varphi}1.5mm$) and bore diameter of lower die(${\varphi}3mm$) were designed for the ASP test. The micro-hardness test was also performed to assess the mechanical properties with artificial aging heat treatment. Material degradation was estimated by ductile-brittle transition temperature(DBTT). The results obtained from the ASP test were compared with those from conventional small punch(CSP) test and CVN impact test for several weldment microstructures. It was found that the ASP test clearly showed the microstructural dependance on the material degradation in the weldment.

• Journal of Mechanical Science and Technology
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• v.18 no.9
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• pp.1604-1613
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• 2004

This paper presents an effective and reliable evaluation method for fracture strength and material degradation of the micro-structure of high temperature service steel weldment using advanced small punch (ASP) test developed from conventional small punch (CSP) test. For the purpose of the ASP test, a lower die with a minimized ${\Phi}$1.5 mm diameter loading ball and an optimized deformation guide hole of ${\Phi}$3 mm diameter were designed. The behaviors of fracture energy (E$\_$sp/), ductile-brittle transition temperature (DBTT) and material degradation from the ASP test showed a definite dependency on the micro-structure of weldment. Results obtained from ASP test were compared and reviewed with results from CSP test, Charpy impact test, and hardness test. The utility and reliability of the proposed ASP test were verified by investigating fracture strength, behavior of DBTT, and fracture location of each micro-structure of steel weldment for test specimen in ASP test. It was observed that the fracture toughness in the micro-structure of FL＋CGHAZ and ICHAZ decreased remarkably with increasing aging time. From studies of all micro-structures, it was observed that FGHAZ microstructure has the most excellent fracture toughness, and it showed absence of material degradation.

• The Transactions of The Korean Institute of Electrical Engineers
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• v.66 no.11
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• pp.1651-1656
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• 2017

This paper deals with the thermal and mechanical properties of ceramic coating material for bus bars. A ceramic coated samples were prepared for the mechanical properties test. There are two types of samples. One is a square shape and the other is a busbar shape. Each sample was deteriorated for 30 days to compare the thermal and mechanical properties with the non-degraded samples. Two thermal properties tests are TGA and flammability tests, and four mechanical properties tests are drop impact test, cross cut, tensile test, and bend test. The ceramic coating material was never damaged by impact and did not separate from aluminum in the cross cut test. In the tensile test, the breakage of the insulating material did not occur until aluminum fractured, and the breakage of the insulating material did not occur until the maximum load in the bending test. The decomposition temperature (melting point) of the ceramic coating material was higher than that of other epoxy insulators. This ceramic coating material is nonflammable and it has excellent fire stability.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.13 no.1
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• pp.66-71
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• 2014

In this research, a material test machine is developed which uses a small electro-magnetic actuator and a leverage mechanism. The leverage mechanism amplifies the force from the electro-magnetic actuator. The electro-magnetic part operates more silently and cleanly than a hydraulic part. In a tooth material study, a test machine does not require a large force capacity because it handles only $4mm^2$-sectioned and short-span specimens. Conventional test machines such as those by Instron and the BOSE Enduratec ELF3200 have too high aforce capacity for a tooth material study. A test machine for a tooth material study requires an acting force only on the order of tens of Newtons (N) operating at several Hertz.

• Composites Research
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• v.23 no.3
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• pp.37-42
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• 2010

The fiber material properties, elastic constant and strength, are the most important factors among the various material properties for the design of composite pressure vessel, because of it's dominant influence on the performance of composite pressure vessel. That is, the deformation and burst pressure of pressure vessel highly affected by the fiber material properties. Therefore, the establishment of test method for exact fiber material properties is a priority item to design a composite pressure vessel. However, the fiber material properties in filament wound pressure vessel is very sensitive on various processing variables (equipment, operator and environmental condition etc..) and size effect, so that it isn't possible to measure exact fiber material properties from existing test methods. The hydro-burst test with full scale pressure vessel is a best method to obtain fiber material properties, but it requires a enormous cost. Thus, this paper suggests a newly developed test method, hoop ring test, that is capable of pressure testing with ring specimens extracted from real composite pressure vessel. The fiber material properties from hoop ring test method showed good agreement with the results of hydro-burst test with full scale composite pressure vessels.

• Journal of the Korean Society for Railway
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• v.7 no.2
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• pp.142-148
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• 2004

When material properties depend much on positions in a material or it is difficult to make test specimens from a material or component, an instrumented indentation test described in ISO 14577-1, 14577-2 or KS B 0950 can be used to measure material properties and damage. In this study, first of all, the principals of the instrumented indentation test, KS B 0950 are introduced and yield strengths, tensile strengths and work hardening exponents of base materials, heat affected zones and weld materials are measured. In addition, the influence of post-weld heat treatment on the material properties is investigated. Finally the fatigue lift of butt welded specimens are evaluated by the local strain approach. To calculate local strains and stresses, elasto-plastic finite element analysis is conducted using the measured properties.

• Composites Research
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• v.19 no.2
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• pp.1-6
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• 2006

The civilian and military agencies require the use of statistic-based allowable to design aerospace vehicles with composite materials. In order to comply this regulation, it is necessary to establish relatively large amount of database, which increases test costs and time. Recently NASA/FAA developed the new method which can satisfy the regulation with smaller test matrix through AGATE(Advanced General Aviation Transport Experiments) program. Especially the concept of material equivalency is very useful when the material has been certified in previous program, and it allows the engineer to use the database with the addition of small test matrix. This paper summarizes the material equivalency and acceptance test methodology so that composite material database can be shared and improve the credibility of the material quality. As a demonstration, the material design allowable of the high temperature carbon/epoxy composite developed domestically was determined with this methodology.

• Proceedings of the KSR Conference
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• 2004.10a
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• pp.516-521
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• 2004

TEEE(Thermoplastic ether-ester elastomer) is expected to reduce the noise and vibration from railway because its unique properties such as porosity. in this study, after building TEEE rail pad at established rail, we conducted practical test and vibration test to inquire the field application and endurance of TEEE material. The test results showed that TEEE material was lower vibration than EVA material, therefore, TEEE material was effective from a vibration reduction point of view.

• Journal of the Korean GEO-environmental Society
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• v.14 no.8
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• pp.5-9
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• 2013

In this study, it was examined a strength characteristic of organic acid material that is eco-friendly and low energy as a soil improving material. The object of this study is to analysis of strength changes with observing the clay mixed organic acid material through the unconfined compression strength test and triaxial compression test during 28 days. As a result of the tests, the strength of clay mixed organic acid material is increased when the more ages are prolonged, the more organic acid material mixture ratio growed. Therefore, in grasping the strength improvement effects of clay by organic acid material mixing, it confirmed that organic acid material as soil improving material is effective through unconfined compression strength test and triaxial compression test. Through this test, the definite strength increase is confirmed according to the mixture of the organic acid material and the possibility of soil improvement is also confirmed based on this result. From now on, detailed examination and field test will help closely to definite strength characteristics.