• 정보처리학회논문지A
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• 제17A권1호
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• pp.33-44
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• 2010

본 논문에서는 생체 모방 로봇을 이용한 관로 모니터링 시스템에 대하여 제안한다. 생체 모방 로봇은 관로를 이동하며 온도, 습도, 진동 등 다양한 정보를 획득한다. 관로를 이동하기 위하여 기본적으로 갖추어야 할 기능은 로봇이 이동하여야 할 관로의 형태를 인식하는 것이다. 관로의 형태 인식을 위한 센서로 적외선 거리 측정 센서를 사용하며, 모터에 연결된 센서는 회전 운동을 하며 측정된 각도 및 거리 정보 데이터를 이용하여 관로의 형태, 각도 등을 인식한다. 관로의 형태 인식은 모터에 의해 회전 운동하는 적외선 거리 측정 센서에 의해 감지되는 관로의 개수와 위치에 의한다. 한번 스캔된 데이터에서 감지되는 관로의 수에 따라 별도의 퍼지 분류기를 이용하여 형태 및 관로의 휘어진 각도 등을 추정하며, 다양한 형태의 관로에 대해 실제 측정된 데이터를 통하여 제안된 시스템이 효율적임을 확인한다.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 춘계학술대회 논문집
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• pp.254-259
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• 2001

There are advantages in the installation of dual subsea pipelines over two separate single lines. In many case it can reduce the cost for trench, back-filling and installation. However the installation of dual pipelines often requires technical challenges. Dual Pipelines should be placed to be stable to external loading not only during the installation but also in the design life. Dual pipelines in trench can reduce the influence of external forces. To investigate applied forces as slope changes, number of experiments are conducted with PIV (Particle Image Velocimetry) in a circulating water channel. Numerical approaches are also made to compare with experimental results. The velocity fields around dual pipelines in trench are investigated and analysed. Comparison of both results show similar pattern of flow around dual pipelines. it is proved that the trench slope affects the pipeline stability significantly. The results can be applied in the stability design of dual pipelines in trench section. The complex flow patterns can be referenced effectively linked in the understanding of fluid around circular bodies in trench.

• Corrosion Science and Technology
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• 제7권4호
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• pp.208-211
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• 2008

Safety operation of main pipelines is primarily provided by anticorrosive monitoring. Anticorrosive monitoring of oil pipeline transportation objects is based on results of complex corrosion inspections, analysis of basic data including design data, definition of a corrosion residual rate and diagnostic of general equipment's technical condition. All the abovementioned arrangements are regulated by normative documents. For diagnostics of corrosion-technical condition of oil pipeline transportation objects one presently uses different methods such as in-line inspection using devices with ultrasonic, magnetic or another detector, acoustic-emission diagnostics, electrometric survey, general external corrosion diagnostics and cameral processing of obtained data. Results of a complex of diagnostics give a possibility: $\cdot$ to arrange a pipeline's sectors according to a degree of corrosion danger; $\cdot$ to check up true condition of pipeline's metal; $\cdot$ to estimate technical condition and working ability of a system of anticorrosive protection. However such a control of corrosion technical condition of a main pipeline creates the appearance of estimation of a true degree of protection of an object if values of protective potential with resistive component are taken into consideration only. So in addition to corrosive technical diagnostics one must define a true residual corrosion rate taking into account protective action of electrochemical protection and true protection of a pipeline one must at times. Realized anticorrosive monitoring enables to take a reasonable decision about further operation of objects according to objects' residual life, variation of operation parameters, repair and dismantlement of objects.

• Journal of Advanced Research in Ocean Engineering
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• 제2권4호
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• pp.158-168
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• 2016

During the installation of crude oil or gas pipelines, which pass through onshore buried pipelines or onshore pipeline from subsea pipeline to onshore plant, countermeasures need to be implemented so as to ensure a sufficient design life by protecting the steel pipes against corrosion. This can be achieved through impressed current cathodic protection method for onshore pipelines and through galvanic sacrificial anode corrosion protection method for offshore pipelines. In particular, in the case of impressed current cathodic protection, isolation joint flanges should be used. However, this makes maintenance control difficult with its installation having a negative impact on price. Therefore, in this study, the most suitable methodology for onshore pipeline protection between galvanic sacrificial anode corrosion protection and impressed current cathodic protection method will be introduced. In oil and gas transportation facilities, the media can be carried to the end users via onshore buried and/or offshore pipeline. It is imperative for the field operators, pipeline engineers, and designers to be corrosion conscious as the pipelines would undergo material degradations due to corrosion. The mitigation can be achieved with the introduction of an impressed current cathodic protection method for onshore buried pipelines and a galvanic sacrificial anode corrosion protection method for offshore pipelines. In the case of impressed current cathodic protection, isolation joint flanges should be used to discontinuity. However, this makes maintenance control to be difficult when its installation has a negative impact on the price. In this study, the most suitable corrosion protection technique between galvanic sacrificial anode corrosion protection and impressed current cathodic protection is introduced for (economic life of) onshore buried pipeline.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2008년도 정기 학술대회
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• pp.561-566
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• 2008

Recently, because of development of the high speed train technology, the vibration loads by train is significantly increased ever than before. This buried gas pipelines are exposed to both repeated impact loads, and, moreover, they have been influencing by vibration loads than pipeline which is not located under vehicle loads. The vibration characteristic of pipeline is examined by dynamic analysis, and variable is only train speed. Since an effect of magnitude of vibration loads is more critical than cover depth, as increasing the train speed, the vibration speed of buried pipelines is also increased. The slope of vibration velocity is changed by attenuation of wave, at train speed, 300 km/h. From the analysis results, the vibration velocity of pipelines is satisfied with the vibration velocity criteria which are established by Korea Gas Corporation. The results present operation condition of pipelines under rail loads has fully sound integrity based on KOGAS specification.

• Journal of Advanced Marine Engineering and Technology
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• 제39권8호
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• pp.828-832
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• 2015

This study is conducted for the evaluation of corrosion and lifetime prediction of fire extinguishing pipelines in residential buildings. The fire extinguishing pipeline is made of carbon steel. Twenty-four samples were selected among all the fire extinguishing pipelines in a building; the selection was based on specimenspositions, pipeline diameters, and pipeline thickness. Analysis was conducted by using the results of visual inspection, electrochemical potentiodynamic anodic polarization test, pitting depth measurements, and extreme value statistics with the Gumbel distribution. The maximum pitting depth and remaining life were statistically predicted using extreme value statistics. During visual inspection, pitting corrosion was observed in several samples. In addition, extreme value statistics demonstrated that there were several pipelines that were very sensitive to pitting corrosion. However, the pitting corrosion was not critical in all the pipelines; thus, it was necessary to change only those pipelines that were severely corroded.

• 한국안전학회지
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• 제21권2호
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• pp.1-6
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• 2006

It is well known that pipelines have the highest capacity and are the safest and least environmentally disruptive form of transporting oil and gas. However, pipeline damage caused by both internal and external corrosion is a major concern threatening the reliability of oil and gas transportation and the soundness of the pipeline structure. In this study, we estimate the allowable damage by comparing the ASTM B31G code to a modified theory considering diverse detailed corrosive forms. The ASTM B31 G code has been developed as the evaluation method for reliability and incident prevention of damaged pipelines based on the amount of loss due to corrosion and the yield strength of materials. Furthermore, we suggest a method for estimating the expected life span of used pipelines by utilizing the reliability method based on major variables such as the depth and length of damage and the corrosion rate affecting the life expectancy of the pipelines.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2001년도 추계학술대회 논문집
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• pp.122-127
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• 2001

As pipelines are often used to transport gas, oil, water and oil products, there are more than one pipeline installed in the offshore field. The size and space of pipelines are various depending on the design specifications. The pipelines are to be designed and installed to secure the stability to external loads during the installation and operation period. The flow patterns are very complex around the pipelines being dependent on incoming flow velocity, pipelines size and space. To investigate the flow patterns, number of experiment are conducted with visualization equipment in a circulating water channel. The flow motion and trajectory were recorded from the laser reflected particles by camera. From the experiment the flow patterns around spaced pipelines were obtained. Also pressure gradient was measured by mano-meter to estimate the hydrodynamic forces on the behind pipeline. The results show that the various sizes and spaces can be affected in the estimation of external load. The complex flow patterns and pressure gradients can be effectively used in the understanding of flow motion and pressure gradient.

• Structural Engineering and Mechanics
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• 제44권5호
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• pp.663-680
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• 2012

Previous major earthquakes revealed that most damage of the buried segmented pipelines occurs at the joints of the pipelines. It has been proven that the differential motions between the pipe segments are one of the primary reasons that results in the damage (Zerva et al. 1986, O'Roueke and Liu 1999). This paper studies the combined influences of ground motion spatial variations and local soil conditions on the seismic responses of buried segmented pipelines. The heterogeneous soil deposits surrounding the pipelines are assumed resting on an elastic half-space (base rock). The spatially varying base rock motions are modelled by the filtered Tajimi-Kanai power spectral density function and an empirical coherency loss function. Local site amplification effect is derived based on the one-dimensional wave propagation theory by assuming the base rock motions consist of out-of-plane SH wave or combined in-plane P and SV waves propagating into the site with an assumed incident angle. The differential axial and lateral displacements between the pipeline segments are stochastically formulated in the frequency domain. The influences of ground motion spatial variations, local soil conditions, wave incident angle and stiffness of the joint are investigated in detail. Numerical results show that ground motion spatial variations and local soil conditions can significantly influence the differential displacements between the pipeline segments.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2002년도 하계학술대회 논문집 A
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• pp.130-132
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• 2002

Because of the continuous growth of energy consumption and also the tendency to site power lines and pipelines along the same route, the close proximity of power lines and buried metallic pipelines has become more and more frequent. Therefore there has been and still is a slowing concern about possible hazards resulting from the influence of power lines on metallic pipelines. Underground pipelines that run parallel to or in close proximity to power lines are subjected to induced voltages caused by the time-varying magnetic fields produced by the power line currents. The induced electro- motive force cause currents circulation in the pipeline and voltages between the pipeline and surrounding earth. This paper analyzes the induced voltage on the gas pipelines buried in parallel with 22.9kV distribution lines. Their magnitude depends on the length of parallelism and on the distance between distribution lines and pipeline.