• 제목/요약/키워드: TLP

검색결과 184건 처리시간 0.025초

Reliability of TLP tethers under extreme tensions

  • Siddiqui, N.A.;Ahmad, Suhail
    • Structural Engineering and Mechanics
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    • 제16권3호
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    • pp.317-326
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    • 2003
  • The tension leg platform (TLP) is a moored floating offshore structure whose buoyancy is more than its weight. The mooring system, known as tethers, is vulnerable to failure due to extreme (maximum and minimum) tensions. In the present study the reliability of these tethers under maximum and minimum tension (ultimate limit state) has been studied. Von-Mises failure criteria has been adopted to define the failure of a tether against maximum tension. The minimum tension failure criteria has been assumed to meet when the tethers slack due to loss of tension. First Order Reliability method (FORM) has been adopted for reliability assessment. The reliability, in terms of reliability index, and probability of failure has been obtained for twelve sea states. The probabilities of failure so obtained for different sea states have been adopted for the calculation of annual and life time probabilities of failure.

시간영역에서 ISSC TLP의 비선형 응답 특성 (Nonlinear Response Characteristics of the ISSC TLP in Time Domain)

  • 이창호
    • 한국해양공학회지
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    • 제20권5호
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    • pp.30-35
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    • 2006
  • In tire presence of incident waves with different frequencies, there are second order sum and difference frequency wave exciting forces due to the nonlinearity of tire incident waves. Although the magnitude of these nonlinear wave forces are small, they act on TLPs at sum and difference frequencies away from those of the incident waves. So, the second order sum and difference frequency waveexciting forces occurring close to tire natural frequencies of TLPs often give greater contributions to high and law frequency resonant responses. Nonlinear motion responses and tension variations in the time domain are analyzed by solving the motion equations with nonlinear wave exciting forces using tire numerical analysismethod. The numerical results of time domain analysis for the nonlinear wave exciting forces on the ISSC TLP in regular waves are compared with the numerical and experimental ones of frequency domain analysis. The results of this comparison confirmed tire validity of the proposed approach.

Dynamic behavior of TLP's supporting 5-MW wind turbines under multi-directional waves

  • Abou-Rayan, Ashraf M.;Khalil, Nader N.;Afify, Mohamed S.
    • Ocean Systems Engineering
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    • 제6권2호
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    • pp.203-216
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    • 2016
  • Over recent years the offshore wind turbines are becoming more feasible solution to the energy problem, which is crucial for Egypt. In this article a three floating support structure, tension leg platform types (TLP), for 5-MW wind turbine have been considered. The dynamic behavior of a triangular, square, and pentagon TLP configurations under multi-directional regular and random waves have been investigated. The environmental loads have been considered according to the Egyptian Metrological Authority records in northern Red sea zone. The dynamic analysis were carried out using ANSYS-AQWA a finite element analysis software, FAST a wind turbine dynamic software, and MATLAB software. Investigation results give a better understanding of dynamical behavior and stability of the floating wind turbines. Results include time history, Power Spectrum densities (PSD's), and plan stability for all configurations.

Ren380 超合金의 보론 塗布法을 이용한 液化誘導擴散接合法의 硏究 (Melting induced diffusion bonding of Rene 80 superalloys using boron doping method)

  • 정재필;강춘식;이보영
    • Journal of Welding and Joining
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    • 제9권3호
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    • pp.26-33
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    • 1991
  • As it takes very long time for the Transient Liquid Phase(TLP) bonding, we tried to reduce the bonding time by changing insert material for the high diffusivity element. On this study boron powder was doped as a insert material on the bonding surface of Rene 80 superalloy, and diffusion treated at 1150.deg.C under vacuum. On this method differently from the TLP bonding the insert material was not melted during bonding but only the base metal reacted with the boron was inducedly melted. Therefore, as this bonding mechanism is different from the existing ones, it is suggested as a Melting Induced Diffusion Bonding. When this process was used for the diffusion bonding, the bonding time including homogenization decreased greatly compared to the conventional TLP bonding.

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규칙파 중 TLP의 유탄성응답 해석 (Hydroelastic Response Analysis of TLPs in Regular Waves)

  • 하영록;이승철;구자삼
    • 동력기계공학회지
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    • 제14권2호
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    • pp.48-54
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    • 2010
  • An improved numerical scheme, to which the hydroelastic method is adapted, is introduced for predicting the motion and structural responses of tension leg platforms(TLPs) in regular waves. The numerical approach in this work is based on a combination of the three dimensional source distribution method and the finite element method. The hydrodynamic interactions among TLP members, such as columns and pontoons, are included in the motion and structural response analysis. The drag forces on the submerged slender members, which are proportional to the square of relative velocity, are included in order to estimate the responses of members with better accuracy. Comparisons with other results verify the works in this paper.

Fe-35Ni-26Cr 주강 액상확산접합부의 고온기계적 특성에 미치는 접합조건의 영향 (Effect of Bonding Condition on High Temperature Mechanical Properties of TLP Bonded Joints of FE-35Ni-26Cr Alloy)

  • 김대업
    • Journal of Welding and Joining
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    • 제18권4호
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    • pp.96-103
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    • 2000
  • This study investigated the effects of bonding temperature and bonding atmosphere on high temperature mechanical properties of transient liquid phase(TLP) bonded joints of heat resistant alloy using MBF-50 insert metal. Specimens were bonded at 1,423~1,468K for 600s. Microconstituents of {TEX}$Cr_{7}(C,B)_{3}${/TEX}were formed in the bonded region when the bonding temperature was low. The amount of microcostituents in the bonded layer decreased with increasing the bonding temperature, and the microconstituents in the bonded layer disappeared at the bonding temperature above 1,468K. The tensile strength of the joints at elevated temperatures increased with the increase the bonding temperature and was the same level as one of the base metal in the bonding temperature over 1,453K. Microstructure and alloying element distributions of the bonded region bonded in Ar and $N_2$atmosphere were similar to those of the bonded in vacuum. The creep rupture strength and rupture lives of joints were almost identical to those of base metal.

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이액상계를 이용한 토양슬러리 반응기에서의 PAH 거동 특성

  • 이재영;백기태;조현정;양지원
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2003년도 추계학술발표회
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    • pp.144-147
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    • 2003
  • In this study, the mass transfer behaviors of phenanthrene, anthracene, and pyrene in soil slurry reactor (SSR) using two-liquid phase (TLP) system were investigated. The mass transfer ratio and rate of PAH in the TLP system using light paraffine oil, which has the highest solubility of PAH, were influenced by the amount of light paraffine oil and mixing speed. When the amount of light paraffine oil decreased from 15 % to 2.5 % (v/v), the mass transfer ratio of anthracene decreased significantly compared with that of phenanthrene and pyrene. As mixing speed increased, the initial mass transfer rate of PAH within 1 day was enhanced. However, each final mass transfer ratio of three PAHs after 5 day was similar irrespective of mixing speed.

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액상확산접합한 Ni기 초내열합금의 등온응고거동에 미치는 모재결정입계의 영향 (The Effect of Base Metal Grain Boundary on Isothermal Solidification Phenomena during TLP Bonding of Ni Base Superalloys)

  • 김대업
    • Journal of Welding and Joining
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    • 제19권3호
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    • pp.325-333
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    • 2001
  • The effect of base metal grain size on isothermal solidification behavior of Ni-base superalloy, CMSX-2 during transient liquid phase (TLP) bonding was investigated employing MBF-80 insert metal. TLP-bonding of single crystal. coarse-grained and fine-grained CMSX-2 was carried out at 1373∼1548k for various holding time in vacuum. The eutectic width diminished linearly with the square root of holding time during isothermal solidification process for single crystal, coarse-grained and fine-grained base metals. The completion time for isothermal solidification decreased in the order ; single crystal, coarse-grained and fine-grained base metals. The difference of isothermal solidification rates produced when bonding the different base metals could be explained quantitatively by the effect of base metal grain boundaries on the apparent average diffusion coefficient of boron in CMSX-2.

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이액상계 생물반응기를 이용한 PAH의 분해

  • 이재영;김용기;양지원
    • 한국지하수토양환경학회:학술대회논문집
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    • 한국지하수토양환경학회 2005년도 총회 및 춘계학술발표회
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    • pp.159-162
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    • 2005
  • In this study, a two-liquid-phase (TLP) bioreactor was conducted to enhance the biodegradation efficiency and rate of PAH. Phenanthrene was degraded efficiently irrespective of the type and the amount of water-immiscible liquid (WIL). The degradation efficiency of anthracene was much higher in paraffine oil than in silicone oil because the mass transfer of anthracene was different in the two WILs. Pyrene was only transferred from soil to WIL during 5 days. It seemed that the degradation of PAH in the TLP bioreactor was mainly dependent on the mass transfer of PAH.

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Ni기 초내열합금의 액상확산접합부 생성상의 금속조직학적 검토 (Metallurgical Study of Microconstituents in Transient Liquid Phase Bended Joints of Ni Base Superalloy)

  • 김대업
    • Journal of Welding and Joining
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    • 제19권1호
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    • pp.75-81
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    • 2001
  • The metallurgical study of microconstituents in transient liquid phase bonded joints of Ni-base single crystal superalloys, CMSX-2 and CMSX-4 was investigated employing MBF-80 insert metal. TLP bonding of specimens was carried out at 1,373~1,523K for 0~19.6ks in vacuum. Three types of microconstituents ; needle-like constituent, dot-like constituent and abnormal shape constituent were formed in the bonded interlayer during TLP bonding operation. All these microconstituents were identified as boride. Microconstituents contain a large percentage of Cr in the early stage of bonding. As increasing the holding time, the amount of Cr was decreased and the amount of W, Co and Re were increased. From the analysis results of electron diffraction pattern by TEM, composition of elements in microconstituents were into MBlongrightarrowM$_{5}$B$_3$longrightarrowM$_2$B type with the increased in holding time. It can be explained by the fact that the relative amount of boron in microconstituents was decreased when the holding time was increased.d.

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