• Title/Summary/Keyword: Shaft alignment

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A Study on Evaluation Method of Member Forces on the Propulsion Shaft of Ship for Damage Protection of Clutch (선박 추진축계 클러치 손상방지를 위한 축계 부재력 평가방법 연구)

  • Shin, Sang-Hoon;Choe, Ick-Hung;Ko, Dae-Eun
    • Journal of the Society of Naval Architects of Korea
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    • v.47 no.3
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    • pp.438-446
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    • 2010
  • The purpose of this study is to establish the proper evaluation method of member forces on the propulsion shaft using strain gages to confirm bearing offset. The strain measurements to find out the bending moments of the shaft have been performed in the yard to be compared with the results of the shaft alignment analysis. The clutch of the propulsion shaft is highly sensitive to shear forces as well as bending moments and the necessity of the measurement of shear forces on the shaft for normal operation of the clutch is recently on the rise. In this study, an evaluation method of the member forces (bending moments and shear forces) of the shaft clutch based on the shaft strain measurement is established. Through the application of this method to the eight $216,000\;m^3$ LNG carriers, the safeties of the clutch systems are evaluated and the better bearing offsets are deduced for the LNG carriers. After adjusting the bearing offsets, all the sea trials of the eight LNG carriers are successfully carried out without any troubles.

Two-Way Car Ferry Thrust Shaft Primary Support Part Structural Integrity Evaluation (양방향 카페리 추진축 1차 지지부 구조건전성 평가)

  • Kang, Byoung-Mo;Oh, Young-Cheol;Bae, Dong-Gyun;Ko, Jae-Yong
    • Proceedings of the Korean Institute of Navigation and Port Research Conference
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    • 2013.10a
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    • pp.163-164
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    • 2013
  • Two-Way CAR-FERRY land and islands, islands to islands, the connection between sustainable marine transportation in conjunction with the increasing demand of tourists, according to the associated coastal maritime tourism and passenger transport has a role. Subsequent Two-Way CAR-FERRY and the increased ease of use due to berthing maritime accidents can be reduced. Two-Way CAR-FERRY as the draft (even) in the state on both sides of the propeller, because the propeller due to the small diameter, low speed forward flight by the reaction at the shaft and propeller damage can occur. Engine output accordingly, linear and torsional vibration reducer by, elastic coupling selection transverse vibration and shaft alignment (Shaft alignment) considering the shaft design (bearing size, width, thickness) and the primary drive shaft support portion of the hull structure of evaluated for quality.

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Developing a Computer Program for the Design of Marine Diesel Engine Shafting (디이젤기관 추진축계 설계를 위한 전산프로그램 개발에 관한 연구)

  • 김영만;전효중
    • Journal of Advanced Marine Engineering and Technology
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    • v.8 no.1
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    • pp.37-48
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    • 1984
  • For the designing propulsion shafting of ship, shaft diameters are usually calculated according to the Society's rules and other scantlings such as a shaft length, coupling and taper parts, etc., are decided according to calculated diameters. And then, the torsional vibration, the lateral vibration and shaft alignment should be reviewed to check whether the resonance points of torsional or lateral vibration appear within the normal operating speed range and the shaft alignment is reasonable. If the results of calculations are unsatisfactory, this process should be repeated until the final condition is determined and the process of this work takes much time to carry out. To simplify the above tedious processes, authors have developed a computer program to fulfill the above design processes at once. This program takes aim at reducing the manual calculating work associated with the propulsion shafting of ship. To confirm the availability of developed computer program, several propulsion shaftings which are driven by diesel engines, have been analysed. The results calculated by authors developed computer program show comparatively good agreements with those of the actual propulsion shafting.

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A Study on Optimum Shaft Alignment Analysis for VLCC (VLCC의 최적 축계정렬해석 연구)

  • Kim Hyu Chang;Kim Jun Gi
    • Special Issue of the Society of Naval Architects of Korea
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    • 2005.06a
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    • pp.134-137
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    • 2005
  • Recently, in VLCC, shafting system is stiffer due to large engine power whereas hull structure is more flexible due to scantling optimization, which can be suffered from alignment damage by incompatibility between shafting and hull, In this study, shafting system without stern tube forward bush was adapted for less sensitive system against external factors. Also, shaft alignment analysis was considered with hull deflection at various ship loading conditions and stern tube after bush of long journal bearing was evaluated by static squeezing pressure and dynamic oil film pressure with sloping control. Whirling vibration was also reviewed to avoid resonance with propeller blade order. So, reliable shafting design for VLCC could be achieved through optimized alignment analysis for the system without stern tube forward bush.

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Oil Whip Phenomena and Countermeasure on Steam Turbine in 350MW Load Thermal Power Plant (350MW급 화력 발전소 증기터빈의 오일 휩 현상 및 대책)

  • 구재량;김연환;배용채;김계연
    • Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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    • 2001.11b
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    • pp.1015-1019
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    • 2001
  • There are several bearing systems at the large steam-turbines in thermal power plant. The bearing system is one of the most important parts of rotating machinery. The steam turbine vibrations mainly depend on the bearing oil and the shaft alignment condition. This paper describes on the steam turbine abnormal vibration due to the oil whip in terms of the shaft alignment in the thermal power plant.

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Development of Elastic Shaft Alignment Design Program (선체변형을 고려한 탄성 축계정렬 설계 프로그램 개발)

  • Choung Joon-Mo;Choe Ick-Heung
    • Journal of the Society of Naval Architects of Korea
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    • v.43 no.4 s.148
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    • pp.512-520
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    • 2006
  • The effects of flexibilities of supporting structures on shaft alignment are growing as ship sizes are Increasing mainly for container carrier and LNG carrier. But, most of classification societies not only do not suggest any quantitative guidelines about the flexibilities but also do not have shaft alignment design program considering the flexibility of supporting structures. A newly developed program, which is based on innovative shaft alignment technologies including nonlinear elastic multi-support bearing concept and hull deflection database approach, has S basic modules : 1)fully automated finite element generation module, 2) hull deflection database and it's mapping module on bearings, 3) squeezing and oil film pressure calculation module, 4) optimization module and 5) gap & sag calculation module. First module can generate finite element model including shafts, bearings, bearing seats, hull and engine housing without any misalignment of nodes. Hull deflection database module has built-in absolute deflection data for various ship types, sizes and loading conditions and imposes the transformed relative deflection data on shafting system. The squeezing of lining material and oil film pressures, which are relatively solved by Hertz contact theory and built-in hydrodynamic engine, can be calculated and visualized by pressure calculation module. One of the most representative capabilities is an optimization module based on both DOE and Hooke-Jeeves algorithm.

A Study on Designing an Effective Support Point for After-Stern Tube Bearings Concerning Shaft Alignment (추진축계 정렬시 선미관 베어링 유효지지점 설정에 관한 연구)

  • Lee, Jae-ung;Kim, Yeonwon;Kim, Jung-Ryul
    • Journal of the Korean Society of Marine Environment & Safety
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    • v.24 no.6
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    • pp.803-809
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    • 2018
  • Generally, the gap-and-sag method is used in the shipbuilding stage before coupling the shafts to check whether they are installed at the same position as designed and derived from shaft alignment calculation. The primary installed propeller shaft becomes a reference point, the position of the remaining shafts are sequentially determined through the gap-and-sag value derived from the deflection and deflection angle at each shaft flange by own weight. If the reference point varies against the design value, it would have a series of effects on the installation of the remaining shafts. Moreover, after coupling the shafts, even if the bearing reaction forces derived from measurement are satisfied by the allowable limit range, consequently it might have an adverse effect on the stability of the shafting system by not being able to estimate the relative slope angle between the propeller shaft and the after-stern tube bearing. In this paper, to deal with above-mentioned phenomenon, the theoretical calculations related to designing an effective support point of the aft stern tube bearing and analysis by measurement is conducted through a case of open-up inspections. Based on this, a shaft installation guideline is proposed to minimize the misalignment related to preventing wiping damage of the after-stern tube bearing.

A study on the analysis of bearing reaction forces and hull deflections affecting shaft alignment using strain gauges for a 50,000 DWT oil/chemical tanker (스트레인 게이지를 이용한 5만 DWT급 석유화학제품운반선의 베어링 반력 및 선체변형량 분석에 관한 연구)

  • Lee, Jae-Ung
    • Journal of Advanced Marine Engineering and Technology
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    • v.40 no.4
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    • pp.288-294
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    • 2016
  • In modern ships, the shafting system often becomes stiff owing to the high engine power, whereas the hull structure becomes more flexible owing to optimization using high-tensile-strength thick steel plates; therefore, more sophisticated shaft alignments are required. In this study, strain gauge-based measurement was conducted under five vessel operating conditions and bearing reaction forces and hull deflections affecting shaft alignment were analyzed for a 50,000 dead weight tonnage oil/chemical tanker that has gained repute as an eco-friendly vessel in recent years. Furthermore, the analytical results from each technique-theoretical calculation, jacking ups, and strain gauges-were cross-checked against each other in order to enhance the degree of accuracy and reliability of the calculation.