• The Journal of the Acoustical Society of Korea
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• v.41 no.6
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• pp.680-690
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• 2022

Vibrations in the pipe system trigger fatigue-related issues and lead to fatal other problems caused by pipe damage. There are numerous studies to analyze and reduce the cause of pipe vibration, among which a small number of studies are being conducted on pipe vibration reduction using friction supports. The study of friction supports, however, focused only on predicting and evaluating the performance of the friction supports and seldomly considered the design perspective of the install location of the supports. Therefore, this study intends to suggest the optimization process for finding the best installation region of friction support to attenuate the vibration of entire piping system. The optimal position of the friction support is predicted only by linear analysis to guarantee optimization efficiency in the design process. The designed friction support location is verified by time domain analysis.

• Journal of the Korean Institute of Gas
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• v.18 no.6
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• pp.14-20
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• 2014

In this study, the stress analysis for the piping support design is performed as per the rules of the ASME Code, Section III, subsection NF-Component Support which provides a simplified method of design analysis for piping support. This method makes use of simple equations and conservative allowable stress limits for design and service loadings. For the base plate, code equation is satisfied within the allowable limits. Both anchor bolts and pipe strap are governed by the their interaction equations. The stresses resulting from various loadings and their combinations are within the allowable limits specified in the above mentioned ASME Code. Thus, it was proved that the structural integrity of the pump assembly was satisfactory.

• Journal of Advanced Marine Engineering and Technology
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• v.39 no.4
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• pp.425-431
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• 2015

LNG (liquefied natural gas) is considered the best alternative eco-fuel, and many studies on the LNG fuel system have been performed to use LNG as the fuel for ships. For the LNG fuel supply system, natural gas transfers from the vaporizer to the engine in the gaseous state with a temperature of $50^{\circ}C$ and a pressure of 35MPa. Therefore, a structural safety evaluation of the double-walled pipelines considering thermal load is essential. In this article, an uniaxial tensile test for super duplex stainless steel, material for double-walled pipe, according to the annealing time was carried out to analyze the thermal effect. In addition, thermo-structural analysis of the high temperature-high pressure double-walled pipe with fixed supports that are now used widely was carried out to evaluate the structural safety. To minimize stress concentration of the connection point between the support and inner pipe, the shapes of the new type support that can slip through inner pipe were proposed, and the supports which has best structural performance was selected using the results from the thermo-structural analyses of new supports and an analysis of the whole double-walled pipeline was performed to ensure structural safety. These results can be used as a database for the design of double-walled pipelines and sliding support.

• Computational Structural Engineering
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• v.9 no.3
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• pp.115-123
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• 1996

A finite element analysis of a trunnion pipe anchor is presented. The structure is analyzed for the case of internal pressure and moment loadings. The stress results are categorized into the average (membrance) and the linearly varying(bending) stresses through the thickness. The resulting stresses are interpreted per Section III of the ASME Boiler and Pressure Vessel Code from which the Primary (B/sub 1/) and Secondary(C/sub 1/) stress indices for pressure, the Primary(B/sub 2R/, B/sub 2T/) and Secondary(C/sub 2R/, C/sub 2T/) stress indices for moment are developed. Several analyses were performed for various structural geometries in order to obtain empirical representation for the stress indices in terms of dimensionless ratios.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 1996.04a
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• pp.27-39
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• 1996

A finite element analysis of a trunnion pipe anchor is presented. The structure is analyzed for the case of internal pressure and moment loadings. The stress results are categorized as average and linearly varying(through the thickness) stresses. The resulting stresses are interpreted per Section 111 of the ASME Boiler and Pressure Vessel Code from which the Primary(B$_1$) and Secondary(C$_1$) stress indices for pressure, the Primary(B$_2$) and Secondary(C$_2$) stress indices for moment are developed. Several analysis were peformed on various structural geometries in order to determine empirical relationships for the stress indices as a function of dimensionless ratios.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05b
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• pp.67-72
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• 1996

수격현상(Waterhammer)으로 인한 과도압력하중은 월성원자력발전소 비상노심냉각계통 (Emergency Core Cooling System : ECCS) 설계의 주요 고려사항이다. 비상노심냉각계통은 특수안전계통으로서 냉각재상실사고(Loss of Coolant Accident : LOCA)후 일차열수송계통을 다시 채워주고 핵연료 손상을 막기위해 노심으로부터 잔열 및 붕괴열을 제거한다. 일차열수송계통으로의 비상냉각수 주입은 고압주입, 중압주입, 저압주입 3 단계로 주입된다. 과도압력이 발생될 것으로 예상되는 고압주입과 중압주입에 대한 6가지 사례들이 ECCS의 배관과 지지대 설계를 위해 고려되었다. 모든 사례에 대한 비상노심냉각계통의 과도압력 현상은 PTRAN 코드에 의해 해석 되었고 해석된 최고과도압력은 설계압력보다 작음을 알게 되었다. 모든 사례의 최고압력과 최고차압은 비상노심냉각계통 배관 및 지지대 설계를 위한 응력해석 자료로서 사용될 것이다.

• Journal of Navigation and Port Research
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• v.45 no.4
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• pp.212-223
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• 2021

The objective of this study was to evaluate structural safety according to environmental conditions acting on the piping of offshore structure and the motion of the structure. As for conditions acting on the piping, the maximum and minimum temperature conditions were used to analyze the design conditions of N2 generator. The motion of the structure was calculated and applied according to the DNV(Det Norske Veritas) rule. Each condition was combined and a total of 26 load combinations were constructed according to thermal load, motion load, and presence or absence of pipe support. Analysis was performed using a commercial program MSC Patran/Nastran. Thermal analysis was performed by applying the steady-state method, Sol 153. Thermal-structural coupled analysis was performed using Sol 101, a linear-static method. As a result of the analysis, the stress tended to increase when temperature inside the pipe was lower in Set 1 and Set 2, when temperature was higher in Set 3, and when the temperature difference between the inside and outside of the pipe in Set 4 was increased. However, the sum of stresses in the condition with only temperature load and the condition with only the kinetic load did not show the same value as the stress in the composite load condition of two loads. That is, the influence of the motion load varied depending on the direction of motion, the arrangement of pipes, and the position of the support. Therefore, it is necessary to comprehensively consider the size and direction of the motion load acting on the piping, the arrangement of the piping, and the location of the pipe supports during the design of piping.

• Proceedings of the Korean Nuclear Society Conference
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• 1996.05c
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• pp.296-301
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• 1996

이 연구의 목적은 원주방향 균열을 가진 페라이틱 배관의 파괴거동을 실험적으로 평가하는데 있다. 한계하중방법, SC.TNP 방법, R6방법, 그리고 ASME Code방법과 같은 여러 파괴거동 평가 방법의 타당성이 PWR 운전조건(압력:15.5MPa, 온도:228$^{\circ}C$)하에서의 직경 16인치의 대규모 배관파괴실험을 통해 조사된다. 모사지진하중, 단일주파수 사인함수하중, 정하중과 같은 여러 가지 형태의 하중이 배관의 하중지지능력에 미치는 영향이 조사된다. 또한 엘보우부위와 직관부의 영향과 표면균열 및 관통균일의 영향 등도 함께 조사된다. 결과는 다음과 같다. (1) 표면균열을 가진 배관의 파괴거동은 한계하중방법과 SC.TNP 방법에 의해 잘 예측할 수 있다. 반면 관통균열의 경우는 한계하중방법에 의해 잘 예측된다. (2) 모사지진하중하에서는 단일주파수 사인함수하중이나 정하중 하에서 보다 하중지지능력이 크게 예측된다. (3) 엘보우부위와 직관부, 관통균열과 표면균열 사이에 파괴거동에 대한 큰 차이는 없다.

• The Bulletin of The Korean Astronomical Society
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• v.37 no.2
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• pp.152.2-152.2
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• 2012

우주발사체 발사를 위해서는 발사대시스템 개발이 필수적이다. 발사대시스템은 기계설비와 추진제공급설비, 관제설비로 구성되며, 그 중 기계설비는 발사지지대(Launch Pad), 이렉터(Erector), 트랜스포터이렉터(Transport-Erector), 케이블마스트(Cable-mast), 자동체결장치(Auto-coupling Device) 총 다섯 부분으로 나눌 수 있다. 발사지지대는 발사 전까지 발사체를 지지하는 구조물로 발사체의 안전을 보장하고 공급배관 및 통신라인의 경로를 제공한다. 이렉터는 발사준비과정에서 수평으로 이송된 발사체를 2개의 대형 유압실린더를 사용하여 기립시키는 장비로 발사 취소 시 발사체를 수평으로 전환한다. 트랜스포터이렉터는 조립공간에서 조립을 마치고 최종점검이 완료된 발사체를 전용차량을 이용하여 발사대로 이동하고 발사체를 안전하게 잡아준다. 자동체결장치는 지상으로부터 발사체로 연결되는 추진제, 압축가스 등의 연결배관을 자동으로 연결/분리하는 장치이다. 케이블마스트는 우주발사체 상단부의 UCU-E(Umbilical Connectors Unit-Electrical)를 통해서 전기, 고압가스, 고온공기 등을 공급하기 위한 통로로 발사 전까지 발사체시스템과 지상장비와의 통신수단이다. 또한 발사체로 연결되는 라인들을 발사 시에 나오는 후류에 의한 충격으로부터 보호하고, UCU-E가 기계적으로 분리되도록 구성되어 있다. 본 논문은 기존에 적용된 케이블마스트에 대한 구성, 기능 및 운용절차에 관한 것으로, 현재 진행 중인 한국형발사체 개발을 위한 기초 자료조사로 활용하고자 한다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.11a
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• pp.450-451
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• 2008