중형 석유화학제품 운반선의 추진축계 안정성 평가에 관한 연구

As the ship has high output and large size with the development of shipbuilding and steel technologies, the shaft stiffness increases, but it is the situation that the hull is deformed much more easily than before due to using high-strength steel plate. Therefore, deep experience and high attention of the designer are required as the propeller shaft cannot endure the reaction force change coming from the deformation of the hull, if the calculation of shaft alignment is done without considering the deformation of the hull. It can be said that the other area that is very closely connected with shaft alignment is the lateral vibration of propulsion shaft system. So, it should be considered in the safety assessment of shafting. It is better that the distance between centers of supporting bearings of the shaft system is longer in terms of shaft system alignment, but in terms of lateral vibration, the natural frequency becomes lower, so there’s a chance that resonance occurs in the range of engine operating speed. The research related to lateral vibration still remains as a problem to be solved due to unclear elements such as supporting bearing’s stiffness in shaft system, oil film’s stiffness, propeller’s exciting force, etc. Until now, it only ensures whether there’s a sufficient margin to avoid the natural frequency of 1st order propeller blades to be within ±20% of the engine nominal speed in Classification Society, international standards, etc. Therefore, when considering such a situation, it is necessary to verify the calculation result of the natural frequency in the lateral vibration with the actual measurement. In the shaft system of a ship, the increase of local load in the stern tube bearing which supports a propeller shaft occurs prominently due to the influence of the propeller weight at the shaft end, similar to the case of the cantilever beam. Especially, the after stern tube bearing is likely to have a concentrated load in the bottom of aft side while the forward stern tube bearing does on the bottom of forward side. While such magnitude and distribution of local load are determined by the relative inclination angle between the shaft and bearing, the bottom of aft stern tube bearing is most affected among them. Such local load can deflect significantly toward the aft end of aft stern tube bearing in case that the shaft sags down, when the eccentric thrust force acts downward due to the propeller force in the hydrodynamic transient status. Case studies by some authors have presented the real-time dynamic behavior analysis of the shaft system in going-straight and turning by using the telemetry system. While the impact analysis of the shaft system in going-straight and turning of ship was carried out by domestic researchers recently, it was difficult to find the case which analyzed real-time dynamic behavior so far, so that it was considered meaningful to review the shaft behavior’s impact on the shaft system through this study. 50,000 DWT oil/chemical tanker is a type of ship emerging recently as a highly efficient eco-friendly ship and it lowered the engine speed by applying de-rating technology. It reduced fuel consumption significantly compared to similar ships and its feature is to maximize propulsion efficiency through applying the propeller of increased diameter. Therefore, some negative changes in terms of shaft alignment should be compared to similar ships, as the change in aft structure and increased weight of the propeller affect the deformation of the hull. Also, as the forward stern tube bearing is skipped, the natural frequency of lateral vibration becomes lower, so that the possibility of resonance in the operating speed range is expected to be slightly increased. After a review of previous researches, it is considered that there’s no comprehensive case study reported yet, which is related to the hull deformation, the lateral vibration and acceleration of the vessel and the shaft behavior in going-straight for 50,000 DWT oil/chemical tanker. Therefore, a theoretical review and analysis of measured data were performed in this study by using finite element analysis, strain gage method and reverse calculation method. And then the results are reported as follows after reviewing in detail the stability of the propeller shaft system of the target vessel. The finite element analysis result expects that the shaft is placed right down compared to the design value when it moves from light loading to full loading due to the hull deformation, and the reaction force of each bearing satisfying allowable values even under deformation. Also, the effect of hull deformation acts as a little positive factor increasing stability of the shaft system by relieving the relative angle of inclination of the aft stern tube bearing. While the hull deformation which is analyzed by using the strain gage method, is expected -2mm from the intermediate shaft bearing and about -4mm from the main engine bearing and it is a little bigger compared to the existing 47,000 DWT class, the increased weight of the propeller and main engine and the aft change due to the increase in propeller diameter are considered as main causes. The reaction force of the bearing supporting shaft system met allowable value like in the finite element analysis result, also in the full deformation and the cross validation result of bearing force obtained by the strain gage method, jack up method, and the shaft alignment program showed good correlations in most conditions so that the reliability of the analysis was able to be confirmed. The calculation result of lateral vibration’s natural frequency showed that resonant revolution speed was located in the area of more than 163.8% compared to MCR, so that it was above the limit value(±20%) and it was confirmed that there was no notable resonance point also in measurement analysis results. In case of 1st order component of lateral vibration, it showed the constant response of bending stress value regardless of rpm generally, it was considered because of run-out value. Furthermore, the measured bending stress was only 10% level of the provided measurement result, so that a negative influence by the lateral vibration was not expected to occur. The review result of the trajectory during the full laden draft operation showed that slight partial friction phenomenon was estimated with 25% of engine load in strain gage position #7. Therefore, it would be necessary to be careful on the long-time operation at 25% engine load to ensure the stability of shaft. strain gage position #5, it was considered acceptable phenomenon which could occur due to different anisotropy in vertical and horizontal stiffness in the intermediate shaft bearing. And while the hit and bounce friction phenomena was suspected at NCR condition (83 rpm) and it was expected to be stabilized after running-in operation. However, periodical monitoring was required to be continued through the shaft open-up survey when docking. Knowing the fact that the shaft direction in strain gage position #7 which was installed at the closest to propeller, moved toward left down direction with increasing engine load at both conditions regarding the shaft behavior. It was determined that the shaft direction in propeller location moved to the right upper direction which was the opposite to the moving direction of the strain gage installed location, and its effectiveness could be confirmed based on the previous study results obtained with direct measurements. Although the method above couldn’t determine the exact displacement component at the center of shaft, it could provide the moving direction’s pattern of propeller shaft by the engine load during operation, so that it was confirmed that it was significant and practical as an alternative method to the direct measurement one in the position of the propeller. Also, the propeller force during going-straight acted as a force lifting the shaft from the aft stern tube bearing and it reduced the possibility of damage to the aft stern tube bearing. Therefore, it was considered to contribute to improve the reliability of the shaft system. If the results obtained in this study are applied to similar type of ships for the shaft alignment and lateral vibration calculation, it is considered that it will help ensure the stability of the shaft system and prevent damages not only in quasi-static but also in dynamic conditions.목 차 제 1 장 서 론 1 1.1 연구의 배경 1 1.2 선행연구(Literature survey) 3 1.2.1 축계정렬 4 1.2.2 축계 횡진동 7 1.2.3 축의 거동 분석 8 1.3 연구의 목적 9 1.4 연구의 내용 및 구성 10 제 2 장 유한요소법에 의한 축계정렬 계산 이론 13 2.1 기본식의 유도 13 2.1.1 횡하중과 모멘트 하중을 받는 부등 단면보의 절점 방정식 13 2.1.2 횡하중과 모멘트 하중을 받는 보의 강성 매트릭스 16 2.2 횡하중과 모멘트 하중을 받는 부등 단면보 절점방정식의 해법 18 2.2.1 절점방정식의 해법 18 2.2.2 지점의 처리 18 2.3 반력 영향계수의 계산 20 제 3 장 축계 횡진동의 이론적 해석 방법 23 3.1 횡진동의 근사계산법 23 3.1.1 Panagopulos의 식 23 3.1.2 수정 Panagopulos의 식 26 3.1.3 Jasper의 식 27 3.1.4 Jasper-Rayleigh의 식 33 3.2 횡진동의 정밀 계산법 36 3.2.1 강성 매트릭스를 이용한 진동방정식의 유도 37 3.2.2 진동방정식의 해법 40 제 4 장 축계 베어링 반력 측정법 43 4.1 잭업법 43 4.1.1 주기관 최후부 베어링 측정 방법 47 4.1.2 주기관 베어링 측정 방법(최후부 베어링 외) 49 4.1.3 선미관 선수베어링과 중간축 베어링의 측정 방법 52 4.1.4 잭업법을 이용한 베어링 지지하중 계산 방법 53 4.1.5 잭업법을 이용한 축 불균형(run-out)량 계산 방법 55 4.2 스트레인 게이지법 55 4.2.1 축계 굽힘모멘트 산출 방법 60 4.2.2 스트레인 게이지법을 이용한 베어링 지지하중 계산 방법 64 4.2.3 스트레인 게이지법을 이용한 축 불균형(run-out)량 계산방법 67 제 5 장 선체 변형을 고려한 추진축계 안정성 평가 69 5.1 선체 변형을 고려한 축계정렬 해석 방법 69 5.2 해석 결과 및 고찰 78 5.3 소결론 89 제 6 장 계측치 역분석을 통한 추진축계 안정성 평가 91 6.1 계측 및 데이터 분석 방법 91 6.2 선체 변형량 예측 및 베어링 반력 계산 결과 96 6.3 소결론 104 제 7 장 축계 횡진동 분석 105 7.1 횡진동 계산 및 분석 방법 105 7.2 결과 및 고찰 107 7.3 소결론 116 제 8 장 가속 및 직진시 축 거동상태 분석 119 8.1 계측 및 데이터 분석 방법 120 8.1.1 측정 설비의 구성(configuration) 120 8.1.2 계측 절차 123 8.1.3 원 신호(raw data)의 처리 124 8.1.4 진동 원인별 궤도(orbit)형태 분석 127 8.2 동적 상태 계측(dynamic measurement) 130 8.2.1 만재흘수 조건(full laden APT tank fullNBE) 139 8.3 소결론 153 제 9 장 결 론 155 참고문헌 157FLF) 130 8.2.2 밸러스트 흘수 조건 (ballast APT tank empt

Fabrication and evaluation of the stress induced PZT films

학위논문(박사) --서울대학교 대학원 :재료공학부,2008.8.Docto

Sword bean의 발아특성과 재배법에 관한 연구

학위논문(석사)--서울대학교 대학원 :농학과,2000.Maste

베어링 강성을 고려한 초대형 컨테이너 운반선의 최적 추진축계 배치에 관한 연구

Recently, damages of the main engine aftmost bearing and the after stern tube bearing tend to increase, as the shafting system becomes stiffer due to the large engine power, whereas the hull structure becomes more flexible due to optimization by using high tensile thin steel plates. Deferences of ship's draft condition and the thermal expansion are some common causative factor in the deformation of main engine bed and double bottom structure of engine room. And this is the reason that more sophisticated shaft alignments are required. Therefore, to obtain the optimum status in shafting alignment at the design stage, it is strongly recommended that the change of bearing reaction force depending on ballast/load condition, the bending moment force occurred by propeller thrust, elastic deformation of bearing occurred by vertical load of shaft mass and etc., should be considered. In this study, the optimum shafting alignment calculation was carried out, considering the number of main engine bearings, thermal expansion. and exploiting the sensitivity index, which indicates the reasonable position of forward intermediate shafting bearing for alignment. The optimal position of bearing in process for alignment is determined by sensitivity index, which is defined as follows. Sensitivity index = where, : Influence coefficient of intermediate bearing to ith bearing : Number of total bearings taken into consideration : Intermediate bearing number According to the above process, the optimal bearing position of forward intermediate shafting was confirmed with smallest sensitivity index. Finally, as the main subject in this study, the elastic deformation on main engine bearings occurred by vertical load of shaft mass were examined thoroughly and analysed allowable load of bearings, reaction influence numbers of all bearings. As the result, a reliable optimum shafting alignment was derived theoretically. To verify these results, they were referred to the engine maker's technical information of main engine installation and being used shafting alignment programmes of both Korean Register of Shipping and Det Norske Veritas, their reliability were confirmed.제1장 서 론 1 제2장 추진축계의 배치문제 및 설계개요 3 2.1 축계배치와 베어링 영향계수 3 2.2 축계배치에 있어서의 문제점 3 2.3 새로운 추진축계의 배치문제 5 2.4 추진축계 배치에 있어서 고려해야 할 사항 7 2.5 추진축계 배치계산의 종류와 의미 8 2.5.1 축계의 합리적인 배치 8 2.5.2 축계의 배치불량 8 2.5.3 축계배치 방법 9 2.5.4 추진축계 배치계산의 기준 10 제3장 유한요소법에 의한 축계배치 계산 이론 13 3.1 기본식 유도 13 3.1.1 횡하중과 모멘트하중을 받는 부등 단면보의 절점방정식 13 3.1.2 횡하중과 모멘트하중을 받는 보의 강성매트릭스 16 3.1.3 횡하중과 모멘트하중을 받는 부등단면보 절점방정식의 해법 17 3.1.4 반력 영향계수의 계산 19 3.2 추진축계의 최적배치 계산방법 21 3.2.1 축계의 최적배치 계산 21 3.2.2 축계의 선형성 22 3.2.3 선형계획 문제 24 3.3 갭과 색의 계산 26 3.4 베어링 반력의 이론적 계산과정 28 3.5 잭-업법(jack-up)을 이용한 실제의 베어링 지지하중 추정방법 31 3.6 잭-업법에 의한 베어링 반력 계측방법 32 제4장 실선 축계의 최적배치 방안 연구 34 4.1 이론에 의한 축계 베어링 반력해석 35 4.2 축계배치 최적화 안 38 4.2.1 주기관 베어링 개수 고려에 따른 반력 비교분석 38 4.2.2 열팽창 효과 고려에 따른 반력 비교분석 40 4.2.3 감도지수를 이용한 중간축 베어링 위치의 최적화 45 4.2.4 10,100 TEU 축계 배치도와 강체 베어링 반력 분석 49 4.2.5 강성을 고려한 베어링 반력 분석 52 제5장 결 론 63 참고 문헌 6

Analytic Time Domain Characterization of Photoresponse of p-i-n Photodiodes and ESQW Symmetric SEEDs

Docto

한국인 정상 성인의 하대정맥 크기의 측정을 통한 심외도관 폰탄수술에서의 도관 크기의 적정성에 관한 연구

학위논문(석사)--서울대학교 대학원 :의학과 흉부외과학전공,2004.Maste

Electrical Tunneling Biosensor for Detecting MMP-9 Using Concentric Electrode Device

학위논문 (석사)-- 서울대학교 대학원 : 전기·정보공학부, 2016. 2. 박영준.암의 중요 바이오마커 (biomarker) 중에 하나인 Matrix metalloproteinase-9 (MMP-9)을 전기적으로 측정함으로써, 개인진단이 가능하게 하는 플랫폼 기술을 개발하였다. MMP-9의 효소역할 통해 분자 체인이 끊어진다고 알려진 펩타이드 (peptide)를 사용하여, peptide와 금 전극 사이의 tunneling 전류의 변화를 측정함으로써 MMP-9을 검출하였다. Tunneling 전류를 증가시키기 위해서 기 사용된 산화환원 리포터 (redox reporter) 역할을 하는 메틸렌 블루 (Methylene blue, MB)를 peptide 말단에 합성한 뒤 동심 구조 전극에 고정화 하여 사용하였다. 바이오 센서를 CMOS회로와 집적시키기 위해서 본 그룹에서 개발된 동심 구조 전극을 사용하였다. 동심구조 전극은 2전극 구조로서 island electrode와 enclosing electrode의 면적이 1000배 이상 차이 나기 때문에 수용액에 대한 전기 이중층 (electrical double layer)의 커패시턴스 (capacitance) 차이로 수용액의 전위가 enclosing electrode의 전압에 고정되는 자기-게이팅 (self-gating) 효과를 가지므로 기준 전극이 없이도 MMP-9에 의한 전류 변화를 검출 가능 할 것이라 예측하였으며, 이를 실험을 통해 확인하였다. 본 연구에서는 전극에 고정화된 MB-peptide가 MMP-9에 의해 잘렸을 때의 전극과 methylene blue 사이의 전자의 이동, 즉 tunneling 전류가 감소함을 확인하였다. 이러한 특성은 MMP-9 이외에 다양한 바이오마커를 검출하는데 유용하게 사용될 수 있는 바이오 센서 플랫폼이 될 것이다.제 1장 서 론 1 1.1 연구의 배경 1 1.2 연구의 목적 12 1.3 논문의 구성 13 제 2장 실험 설계 14 2.1 진단 센서 소자 구조 14 2.2 Peptide substrate for MMP-9 20 2.3 Tunneling state로서의 Methylene blue (MB) 21 2.4 MB-peptide 기반 MMP-9 검출 센서 제작 23 2.5 MMP-9 센서의 감응 원리 25 제 3장 결과 및 분석 27 3.1 MB-peptide 기반 tunneling biosensor의 전류특성 분석 27 3.2 전압 인가에 따른 MB-peptide biosensor의 energy state 변화 분석 33 3.3 시간에 따른 전류 변화 측정 37 3.4 MMP-9 농도에 따른 전류 변화 측정 39 제 4장 결론과 앞으로 연구 제안 41 참고문헌 43 Abstract 47Maste

해상도 이내로 밀집된 물체군에 대한 모노펄스 각도 추정 알고리즘 분석

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