• 대한기계학회논문집
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• 제10권5호
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• pp.713-723
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• 1986

본 논문에서는 비금속성 재질(SiO$_{2}$)로 만든 윅의 열전달 특성을 실험적 해석적 방법으로 연구했다. 먼저 비금속 윅을 단독으로만 실험하여 해석해와의 일치 성을 밝히고, 윅의 성능 개선을 위해 결합재의 첨가가 히이트파이프 증발부의 열전달 에 미치는 영향을 ADI해석 해법으로 예측하였다. 따라서 고온용 히이트파이프 뿐만 아니라 ,저온용에서도 비금속윅의 사용을 위한 가치 판단을 하고 비금속성 재질(SiO S12 등)이 윅으로서 넓게 이용 될수 있다는 가능성을 제시하는데 그 목적이 있다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2000년도 가을 학술발표회 논문집(II)
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• pp.983-988
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• 2000

Anchoring systems with structural stability and endurance have been one of the most important elements for PSC structures, especially for the structures using non-corrosive FRP tendons. FRP tendons are in increasing use for underground and coastal structures constantly contacted with fresh water or sea water because of their superiority to metallic ones in corrosion-resistance. In this study new non-metallic anchoring system for FRP tendons has been tested and investigated. The newly developed anchoring system utilizes FRP pipes and HEM (Highly Expansive Mortar). The major factors considered in this experiment were expansive pressure of HEM during its hydration and the strength of GFRP(Glass Fiber Reinforced Plastic) Pipe. Anchoring forces of the new anchoring system were investigated from the pull-out testes. The authors analyzed pull-out procedures of the FRP tendons in the various pipe filled with HEM and suggested an improved idea to develop novel non-metallic anchoring system for FRP tendons

• 한국신뢰성학회지:신뢰성응용연구
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• 제15권3호
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• pp.197-206
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• 2015

Failure analysis of pre-insulated pipe (SPPS 380, 400A) transporting high temperature water ($95{\sim}110^{\circ}C$) for a plant was carried out. The damaged area (${\Phi}5mm$) of pre-insulated pipe was found only on welds. The chemical composition of damaged pipe meets specification of carbon steel pipes for pressure service (KS D 3562). As results of microstructure analysis, crack propagated from outer to inside after pitting corrosion occurred on the outside surface. The non-metallic inclusion existed on the end of crack. And the non-metallic inclusion continuously and linearly formed along with the bond line of welds. Based on SEM-EDS analysis, the nonmetallic inclusions have higher Manganese (Mn) and Oxygen (O) content but sulfur (S) was not detected. As results of water quality analysis, hydrogen ion concentration and minerals like Fe, Mg, Si were in low level. But the content of dissolved oxygen (11.2 ppm) was slightly higher than that of standard. It seems that the cause of damaged pipe is grooving corrosion due to MnO inclusion formed on bond line and corrosion took place nearby welds.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2023년도 봄 학술논문 발표대회
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• pp.301-302
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• 2023

In this study, we aimed to identify changes in fire resistance according to the type of sleeves used for pipe penetrations and to examine their accreditation of fire resistance performance and use them as basic data. The test results of fire resistance according to the type of sleeve used in non-metallic pipe facilities showed that the temperature on the support side was higher for sleeves with higher thermal conductivity. For the temperature on the surface of the pipes, in the case of galvanized steel plates, steel pipes, and structures without sleeves, the highest temperature was observed after the expansion of the firestop material for 46 to 53 minutes and then decreased. PVC sleeves showed a steady increase in temperature until 53 minutes, after which the temperature did not increase further. In addition, for non-metallic pipes, the effect of the type of sleeve on fire resistance is considered to be insignificant because the lower part (heating direction of the furnace) under the support structure is cut off to block the heat during the two-hour fire resistance test.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2001년도 춘계학술발표대회 논문집
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• pp.23-28
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• 2001

Since non-corrosive Fiber Reinforced Polymer(FRP) tendons have been in increasing use for underground and coastal structures constantly contacted with fresh water or sea water because of their superiority to metallic ones in corrosion-resistance, new non-metallic anchoring system for FRP tendons has been developed and investigated to verify the effectiveness of tendon force, which consist of mainly FRP pipes and Highly Expansive Mortar(HEM). The major factors considered in this experiment were expansive pressures of HEM during its hydration, sleeve lengths and types, and anchoring methods of tendon. New anchoring system were investigated from the pull-out tests. The pull-out procedures of the FRP tendons in the various pipe filled with HEM were analyzed and improved ideas were suggested to develop novel non-metallic anchoring system for FRP tendons The pull-out tests for the FRP tendon and new non-metallic anchoring system were conducted. The results show that non-metallic anchoring system for the FRP tendon has been more stablized due to the gradual expansive pressrure of HEM, as tims goes. Since tile lower stiffness of FRP pipes causes the weakness of anchoring force, it requires the increase of stiffness using a carbon fiber or an increased section area.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.322-325
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• 2007

This paper suggests a non-contact sensor for measuring bending vibration of a non-metallic cylinder in two orthogonal directions simultaneously. Recent research shows that a solenoid can pick up bending vibrations of a nonmetallic cylinder based on the reversed Lorentz force mechanism if an electrical conductive patch is attached to the cylinder. In this work, pairs of specially designed patches are used to make two independent paths for the current induced by bending vibrations, which enables the measurement of bending vibrations along two orthogonal directions simultaneously. The working performance of the developed sensor was verified by using two accelerometers.

• 한국소음진동공학회논문집
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• 제18권4호
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• pp.381-385
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• 2008

This paper suggests a non-contact sensor for measuring bending vibration of a non-metallic cylinder in two orthogonal directions simultaneously. Recent research shows that a solenoid can pick up bending vibrations of a nonmetallic cylinder based on the reversed Lorentz force mechanism if an electrically conductive patch is attached to the cylinder. In this work, pairs of specially designed patches are used to make two independent paths for the current induced by bending vibrations, which enables the measurement of bending vibrations along two orthogonal directions simultaneously. The working performance of the developed sensor was verified by using two accelerometers.

• Nuclear Engineering and Technology
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• 제53권3호
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• pp.1004-1012
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• 2021

High density polyethylene (HDPE) pipe has many advantages over metallic pipe, and has been used in non-safety related application for years in some nuclear power plants (NPPs). Recently, HDPE pipe was introduced into safety related applications. The main difference between safety-related and non-safety-related pipes in NPPs is the design method of extra loadings such as gravity, temperature, and earthquake. In this paper, the mechanical behavior of HDPE pipe under various loads in pipe gallery was studied by finite element analysis (FEA). Stress concentrations were found at the fusion regions on inner surface of mitered elbows of HDPE pipe system. The effects of various factors were analyzed, and the influence of various loads on the damage of HDPE pipe system were evaluated. The results of this paper provide a reference for the design of nuclear safety-related Class 3 HDPE pipe. In addition, as the HDPE pipes analyzed in this paper were suspended in pipe gallery, it can also serve as a supplementary reference for current ASME standard on Class 3 HDPE pipe, which only covers the application for buried pipe application.

• 한국산학기술학회논문지
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• 제22권2호
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• pp.296-301
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• 2021

GPR은 전자파를 지반 또는 대상물에 방사시켜 반사체에서 돌아온 반사파를 이용하는 탐사법으로써 광산의 지반침하나 건설현장의 비파괴 조사, 지반조사, 지하시설물 탐사 등에 활용되고 있다. 본 연구에서는 네트워크 RTK와 연계한 GPR을 이용한 비금속 상수관의 탐사에 대한 활용성을 제시하고자 하였다. GPR을 이용하여 연구대상지 상수관에 대한 데이터를 취득하였으며, 상수관로에 대한 위치 및 매설 심도를 측정하였다. 정확도 평가를 위해 GNSS 관측 성과와 GPR 탐사 결과를 비교하였으며, -0.16m ~ 0.15m의 편차를 확인하였다. 이러한 결과는 공공측량 작업규정의 기기성능을 만족하는 것으로 GPR을 이용한 상수관의 탐사가 가능함을 제시하였다. GPR은 기존 금속관로탐지기에서와 같은 접지 설치가 필요하지 않기 때문에 지하시설물 탐사를 위한 작업의 효율성 증대에 기여할 것이며, GPR을 이용한 탐사는 금속 및 비금속 지하시설물에 대한 위치와 심도를 동시에 취득할 수 있어 GIS 시스템 구축을 위한 데이터로 이용이 가능하다. 향후 추가적인 연구를 통해 금속 및 비금속관로 탐사와 콘크리트, 아스팔트 등 지면 매질에 따른 탐사 특성비교 연구가 이루어진다면 GPR을 이용한 지하시설물 탐사의 다양한 활용성을 제시할 수 있을 것이다.

• Corrosion Science and Technology
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• 제14권3호
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• pp.120-126
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• 2015

The usage of bending products recently have increased since many industries such as automobile, aerospace, shipbuilding, and chemical plants need the application of pipings. Bending process is one of the inevitable steps to fabricate the facilities. Induction heat bending is composed of compressive bending process by local heating and cooling. This work focused on the effect of induction heat bending process on the properties of ASME SA312 Gr. TP304 stainless steel pipes. Tests were performed for base metal and bended area including extrados, intrados, crown up, and down parts. Microstructure was analyzed using an optical microscope and SEM. In order to determine intergranular corrosion resistance, Double Loop Electrochemical Potentiokinetic Reactivation (DL-EPR) test and ASTM A262 practice A and C tests were done. Every specimen revealed non-metallic inclusion free under the criteria of 1.5i of the standard and the induction heat bending process did not affect the non-metallic inclusion in the alloys. Also, all the bended specimens had finer grain size than ASTM grain size number 5 corresponding to the grain sizes of the base metal and thus the grain size of the pipe bended by induction heat bending process is acceptable. Hardness of transition start, bend, and transition end areas of ASME SA312 TP304 stainless steel was a little higher than that of base metal. Intergranular corrosion behavior was determined by ASTM A262 practice A and C and DL-EPR test, and respectively step structure, corrosion rate under 0.3 mm/y, and Degree of Sensitization (DOS) of 0.001~0.075% were obtained. That is, the induction heat bending process didn't affect the intergranular corrosion behavior of ASME SA312 TP304 stainless steel.