• Title, Summary, Keyword: Topside

Search Result 94, Processing Time 0.042 seconds

A Study on the Characteristic of Stress Behavior of Topside Weldment Welded after Launching (진수후 데크 topside 용접부의 응력 거동 특성에 관한 연구)

  • Lee, Dong-Ju;Shin, Sang-Beom
    • Proceedings of the KWS Conference
    • /
    • /
    • pp.58-58
    • /
    • 2010
  • The purpose of this study is to evaluate the structural safety at the topside weldment of hull structure, which was welded after launching. For it, the variations of residual stress and distortion at the topside weldment with loading conditions such as hull girder hogging bending moment after launching and free initial loading state was evaluated by using FEA. And the maximum stress range at the weldment under design loads specified by classification society was evaluated by FEA. In this case, the residual stress and welding distortion at the topside weldment was assumed to be initial imperfection. In accordance with FEA results, regardless of initial loading condition, tensile residual stress was found. However, the residual stress and welding distortion at the topside weldment produced under hogging condition was less than those of topside weldment under free loading state. That is, the amount of residual stress at the topside weldment decreased with an increase in the amount of tension load caused by hogging condition. It was because the compressive thermal strain at the topside weldment produced during welding was reduced by tensile load. However, the maximum stress range at the topside weldment under maximum hull girder bending moment was almost similar regardless of initial loading condition. So, if the problem related to the soundness of weldment is not introduced by initial load, the effect of initial loading condition during welding on fatigue strength of topside weldment could be negligible.

  • PDF

The Analysis of the Topside Additional Layer of Martian Ionosphere Using MARSIS/Mars Express Data

  • Kim, Eojin;Seo, Haingja;Kim, Joo Hyeon;Lee, Joo Hee;Kim, Yong Ha;Choi, Gi-Hyuk;Sim, Eun-Sup
    • Journal of Astronomy and Space Sciences
    • /
    • v.29 no.4
    • /
    • pp.337-342
    • /
    • 2012
  • In this study, the transient second or third layer on the topside of the Martian ionosphere were investigated with the most recently released Mars advanced radar for subsurface and ionospheric sounding/Mars Express data obtained from January 2010 to September 2011 to study the correlation between these topside additional layers and surface magnetic fields, solar zenith angle and solar activities. When examining the zones where the topside layer appeared, the occurrence rate of the topside layer was low at the areas with a strong Martian crustal magnetic field as observed by the Mars global surveyor. The occurrence rate of additional layers on the Martian topside ionosphere decreases as the solar zenith angle increases. However, these layers appeared significantly near the terminator of which solar zenith angle is $90^{\circ}$. In comparison between F10.7 which is the index of solar activities and the occurrence rate of the topside layer by date, its occurrence rate was higher in 2011 than in 2010 with less solar activities. The result of this study will contribute to better understanding of the environments in the topside of the ionosphere through the correlation between the various conditions regarding the Martian ionosphere and the transient layer.

A Noise Characteristics and Countermeasures of FPSO Topside (FPSO Topside의 소음특성 파악 및 저감대책)

  • Kim, Dong-Hae;Kim, Sung-Hoon;Chung, Kun-Hwa
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.73-76
    • /
    • 2005
  • Recently, the demand for the Floating, Production, Storage, and Offloading facility (FPSO) which has some economic and technical advantages, has increased in offshore oil production areas. FPSO vessel dose not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise sources such as gas turbines, compressors, and pumps, are located on top of the hull (Topside area). In general, the noise regulation for the offshore structure is severer than that of the cargo ship and acceptable noise limit of cabin is specified as 45 dB(A). This paper describes the noise characteristics and the countermeasures for FPSO Topside area through investigation of noise analysis and site measurement results. Proper countermeasures, considering the characteristics of sources and receiver spaces, were applied from the noise prediction and various measurement results. Finally, this ship was successfully delivered with excellent noise properties.

  • PDF

Vertical Scale Height of the Topside Ionosphere Around the Korean Peninsula: Estimates from Ionosondes and the Swarm Constellation

  • Park, Jaeheung;Kwak, Young-Sil;Mun, Jun-Chul;Min, Kyoung-Wook
    • Journal of Astronomy and Space Sciences
    • /
    • v.32 no.4
    • /
    • pp.311-315
    • /
    • 2015
  • In this study, we estimated the topside scale height of plasma density (Hm) using the Swarm constellation and ionosondes in Korea. The Hm above Korean Peninsula is generally around 50 km. Statistical distributions of the topside scale height exhibited a complex dependence upon local time and season. The results were in general agreement with those of Tulasi Ram et al. (2009), who used the same method to calculate the topside scale height in a mid-latitude region. On the contrary, our results did not fully coincide with those obtained by Liu et al. (2007), who used electron density profiles from Arecibo Incoherent Scatter Radar (ISR) between 1966 and 2002. The disagreement may result from the limitations in our approximation method and data coverage used for estimations, as well as the inherent dependence of Hm on Geographic LONgitude (GLON).

A Study of the Design for the Topside Module Support Structure of an Offshore Floater (해양 플로터 상부모듈 지지구조의 설계에 관한 연구)

  • Song, Myung-Keun;Jang, Beom-Seon;Ko, Dae-Eun
    • Journal of Ocean Engineering and Technology
    • /
    • v.24 no.4
    • /
    • pp.53-58
    • /
    • 2010
  • Offshore floater such as FPSO, drillship is composed of topside and hull side, and the interface structure is called topside module support. In this study, practical considerations were investigated for the design of topside module supports, from the concept design stage to the final stage of structural determination, in view of design efficiency and construction productivity. The effects of welding design factors of topside module support, such as welding throat thickness, sectional welding area, and welding man-hours, were compared and analyzed closely with respect to productivity. The current status and problems regarding the application of deep or full penetration welding are discussed, and a direct-calculation method is suggested as a possible solution to these problems.

A Study on the Structural Behavior of FPSO Topside Module by Support Condition (지지조건에 따른 FPSO 상부 모듈의 구조적 거동에 관한 연구)

  • Jang, Beom-Seon;Ko, Dae-Eun
    • Journal of the Korea Academia-Industrial cooperation Society
    • /
    • v.19 no.11
    • /
    • pp.18-23
    • /
    • 2018
  • FPSO consists of topside modularized plants for production of crude oil, and hullside structures that serve as support for the topside and storage of produced crude oil. The structural behavior of the FPSO topside module and its supporting hull depends on the interface structure that connects them, and the interface structure consists of a combination of individual unit support structures called Module Support Seat (MSS). Types of interface structures are various and, accordingly, the basic design of the FPSO topside module structure is greatly influenced, so various design methods should be considered from the initial design phase. Structural design of FPSO topside module requires consideration of the number of MSSs, connection type, and structural analysis options such as the range of finite element models, load conditions, and boundary conditions for verification of structural strength. In this study, the comparison combination cases for the above considerations were derived and the strength evaluation was performed, and the structural behavior characteristics of the topside module were compared and analyzed through a detailed review of the analysis results. The results of this study are considered to be a good reference for designing a more reliable topside module structure.

Daylighting Performance of Topside Lighting Systems for Different Orientations (방위에 따른 정측창 시스템의 채광성능 평가)

  • Kong, Hyo-Joo;Lee, Jin-Seoung;Ahn, Hyun-Tae;Kim, Jeong-Tai
    • Journal of the Korean Solar Energy Society
    • /
    • v.29 no.1
    • /
    • pp.11-17
    • /
    • 2009
  • Daylighting is core of sustainable design in most buildings. Well-designed daylighting systems can significantly reduce or even eliminate the electric lighting loads during the day time, including air conditioning energy loads. Among window systems. the topside lights systems including monitor lighting, sawtooth lighting, sunscoop and, lightscoop is one of the most popular apparatus to improve the lighting quantity. Also they are important both in terms of energy savings and visual quality. The objective of this study is to analyse daylighting performance of topside lighting system for different orientations. Four types of topside lighting system were tested and comparpd: monitor lighting, sawtooth lighting, lightscoop and sunscoop. Totally 25 measuring points of illuminance on the horizontal plane were monitored from 09:00 to 17:00 on October 6, 2008. Agilent data logger and photometric sensors Li-cor were used. Comparisons with a light factor is discussed. The results found in this study would mean that there were no significant differences in light factor between three cases.

Noise Characteristic and Control of FSO (부유식 석유 저장 하역 선박(FSO)의 소음 특성 및 제어)

  • 이장우;김동해
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
    • /
    • /
    • pp.335-338
    • /
    • 2002
  • 본 논문은 부유식 석유 저장 하역 선박(FSO)의 소음 특성 및 해석 기법에 관한 것이다. FSO의 선실 소음 수준은 일반 상선과는 달리 선실 내부에 있는 소음원 이외에도 topside에 있는 각종 소음원들의 영향을 크게 받는다. 따라서, topside에 있는 각종 소음원들이 선실의 소음수준에 미치는 영향을 정확히 평가하는 것이 중요하다. 일반적으로 FSO의 소음해석은 옥외 및 선실 소음 해석으로 구분하여 수행한다. 본 논문에서는 topside에 있는 각종 소음원들의 공기음 전파 특성 해석은 ISO 9613에 근거한 프로그램을 이용하였고, 고체음 전파 특성은 파워 흐름 해석법을 이용하였다. 또한 선실 소음 해석은 통계적 에너지 해석법(SEA)을 이용하였으며, 해석 결과로부터 높은 소음 수준이 우려되는 구역에 대한 방음 대책을 제시하였다. 위의 선실 소음 해석 결과는 향후 FSO의 topside에 있는 각종 소음원들에 의한 선실의 소음 해석 기법 정립에 기여할 것으로 기대된다.

  • PDF

Case Study for Development of Maintenance System for Equipment of LNG-FPSO Topside (LNG-FPSO Topside 장비를 위한 보전시스템 개발을 위한 사례 연구)

  • Lee, Soon-Sup;Kim, Jong-Wang
    • Journal of Ocean Engineering and Technology
    • /
    • v.28 no.6
    • /
    • pp.533-539
    • /
    • 2014
  • A maintenance system for an offshore plant uses an optimal maintenance method, process, and period based on operation information data and economic evaluation techniques. Maintenance is performed after one or more indicators show that equipment is going to fail or that equipment performance is deteriorating. A maintenance system is based on the use of real-time data to prioritize and optimize the LNG-FPSO topside equipment resources.

A Study on the Model of Equipment Layout Verification for Offshore Plant Maintenance Equipment Engineering (해양플랜트 유지보수장치 엔지니어링을 위한 장비 배치 검증수행모델에 관한 연구)

  • Han, Seong Jong;Park, Peom
    • Plant Journal
    • /
    • v.13 no.4
    • /
    • pp.41-47
    • /
    • 2017
  • This paper is a study on validation model that can verify the arrangement of equipment constituting offshore plant using system engineering approach in offshore plant tender stage. In order to design offshore plant topside maintenance equipment, topside layout verification should be preceded. However, there are many errors in the bidding stage due to the FEED results that are not perfect, the verification can not be performed sufficiently due to the limitation of the bidding period and others reasons. Therefore, we propose a validation model that can effectively verify the equipment layout within a limited condition by simplifying the main process in the system engineering process, which is a multidisciplinary approach, and confirmed through the Functional Deployment Model. Also, we verified the validation model for topside equipment deployment through case studies.

  • PDF