• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 추계학술대회논문집
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• pp.307-310
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• 2000

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. The basic characteristics of a 343,000 DWT class FPSO which is being built in Hyundai Heavy Industries and shall be installed in offshore Angola, is almost same as that of oil carriers. However, she do not have self-propulsion system, but has additional facilities for oil production and positioning system. Main noise source contributing to the cabin noise of the accommodation, are classified into the machine in the engine room and the deckhouse, HVAC system, and the topside equipments. In general, the noise regulation for the offshore structure is much severer than that of the common commercial ships and the maximum acceptable sound pressure level of cabins is specified in 45dB(A). This paper describes the procedure of noise analysis along with its results. Noise analysis has been carried out for the case of emergency diesel generator running condition and the case of normal production condition and the results has been compared with the measurement results of the first case. Based on the results, proper countermeasures to reduce excessive noise level has been applied considering the characteristics of sources and receiver spaces and can be satisfied the specifications at all spaces.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2004년도 추계학술대회 논문집
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• pp.101-105
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• 2004

The traction drive have a high power transmission efficiency and small size, a light weight, a low noise. So it is expected that alternative drive part of engine. Because it is necessary stillness that essential condition of drive part used moving tool in a room, it has many-sided in field of application. This traction drive is better suitable than other speed reducer as drive part of electric wheelchair. Also it is sufficiently necessary capacity of existing advanced product as apply traction drive to electric wheelchair.

• 유체기계공업학회:학술대회논문집
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• 유체기계공업학회 2006년 제4회 한국유체공학학술대회 논문집
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• pp.165-168
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• 2006

Due to the distinct advantages of comfort, drive ability and fuel economy standard, the variable displacement swash plate type compressor which can control the compressor displacement by increasing of reducing the swash plate angle has developed for automotive air-conditioning system. That can be obtained constant temperature of car room on the variation cooling capacities of engine speeds. In this paper we investigated the improvement of internally controlled variable displacement swash plate compressor on noise.

• 대한조선학회 특별논문집
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• 대한조선학회 2013년도 특별논문집
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• pp.85-89
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• 2013

In the engine room and the aft body, there are so many fluid tanks such as fresh water tank and oil tank. The vibration analysis for the fluid tank structures has to consider the added mass effect due to the fluid. However, it is known that the result of the fluid tank has the difference according to the boundary condition of the fluid field such as infinite fluid and finite fluid. In this paper, a numerical case study is carried out for the research about the vibration characteristics of the fluid tank with various fluid field. In addition, an experimental study is carried out to verify the validity of the vibration analysis for the fluid tank structure.

• 한국소음진동공학회논문집
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• 제19권8호
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• pp.795-801
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• 2009

This paper presents an optimal design of a magnetorheological(MR) fan clutch based on finite element analysis and also presents torque control of engine cooling fan using a sliding mode control. The MR fan clutch is constrained in a specific volume and the optimization problem identifies the geometric dimension of the fan clutch that minimizes an objective function. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initially designed clutch. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. After describing the configuration of the MR fan clutch, the viscous torque and controllable torque are obtained on the basis of the Bingham model of MR fluid. Then, a sliding mode controller is designed to control the torque of the fan clutch according to engine room temperature and control performance is evaluated through computer simulation.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.329-330
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• 2008

The 181,000 DWT Bulk Carrier has a different deck house type, which is not typical for previous bulk carriers, to meet the new international rules for bulk carriers. This new deck house has much smaller transverse breadth than the hull's transverse breath, resulting in large levels of the transverse response of the deck house. In addition, the longitudinal response of the funnel showed rather a large magnitude of vibration, which are excited by the ship's main excitations such as the main engine H-moment and the propeller surface forte when the ship operates at the NCR and the MCR speeds In the ballast condition. To solve these issues, the global forced vibration analysis has been performed for the ship and the ship structure has been modified to reduce the vibration level by increasing the girder depth and adjusting the engine room tank arrangement.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 춘계학술대회 논문집
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• pp.633-638
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• 2009

This paper presents an optimal design of a magnetorheological(MR) fan clutch based on finite element analysis and also presents torque control of engine cooling fan using a sliding mode control. The MR fan clutch is constrained in a specific volume and the optimization problem identifies the geometric dimension of the fan clutch that minimizes an objective function. The objective function for the optimization problem is determined based on the solution of the magnetic circuit of the initially designed clutch. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. After describing the configuration of the MR fan clutch, the viscous torque and controllable torque are obtained on the basis of the Bingham model of MR fluid. Then, a sliding mode controller is designed to control the torque of the fan clutch according to engine room temperature and control performance is evaluated through computer simulation.

• 한국안전학회지
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• 제12권4호
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• pp.191-200
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• 1997

This paper discusses prediction of the sound pressure level produced by simple engine exhaust systems(plain pipe, plain expansion chamber pipe, plain expansion chamber with internally extended inlet and outlet pipe, perforated pipe enclosed in a plain expansion chamber) and a computer program has been developed which predicts the sound pressure level and the frequency spectrum. The program utilizes unsteady flow gas dynamic theory and acoustic theory to predict the pressure-time history in the exhaust system and the mass flow rate-time history at the open end of the system and the sound pressure levels(1/3 Octave band levels) and the frequency spectrum in semi-anechoic room. The predictions are compared with measured levels and show a high degree of correlation.

• 해양환경안전학회지
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• 제29권4호
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• pp.389-394
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• 2023

근래 산업은 기계 자동화로 변화하고 있는 추세이며, 선박도 센서를 통해 기기 정보를 디지털 정보로 얻는다. 하지만 선박은 기기상태 점검을 위해 선원들이 정해진 시간마다 기관실을 순찰하며 기기들의 정보를 아날로그 게이지를 통해 확인하는데, 이는 순찰 중에 선원에게 발생할 수 있는 모든 안전 위험은 물론 시간과 기회비용 또한 소모된다. 자율이동로봇을 이용한 기관실 순찰 방법은 선원의 안전 위험은 물론 시간과 기회비용도 소모되지 않기 때문에 해결책으로 활발히 연구 중이다. 자율이동로봇을 이용한 아날로그 게이지 판독은 로봇이 게이지를 인식하기 위한 디지털화가 필요하다. 이를 위해 본 연구에서는 이미지 처리를 이용하였다. 아날로그 게이지 이미지는 이미지 전처리를 통해 노이즈 제거 및 특징을 부각 시켰다. 이미지 전처리를 완료한 이미지는 이미지 처리를 통해 아날로그 게이지의 중심점, 지침점, 최소값 및 최대값을 검출하였다. 이 점들을 연결한 직선을 통해 최소값부터 최대값까지의 각도 및 최소값부터 지침점까지의 각도를 획득하였다. 각도는 수식을 통해 현재 아날로그 게이지가 나타내고 있는 값을 디지털화하여 나타내었다. 실험을 통해 이미지 처리를 통한 아날로그 게이지의 디지털화가 잘되어 게이지의 현재 지시값을 근사하게 나타냄을 확인할 수 있었다. 본 알고리즘을 순찰로봇에 적용한다면 기관실 순찰을 위한 선원의 안전 위험 및 시간과 기회비용까지 보전 할 수 있을 것으로 사료된다.

• 한국수산과학회지
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• 제12권3호
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• pp.125-130
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• 1979

1978년 8월 23일 부터 동년 10월 20일 사이에 우리 나라의 남부와 싱가폴 북부 해상에서 새바다호의 순항, 예망, 표박시의 선박소음에 관하여 실험한 결과를 요약하면 다음과 같다. 1. 외부 갑판상의 가장 높은 소음원은 연돌로 돌출하는 배기소음이고, 연돌뒤(No.9)에서 순항, 예망, 표박시 92,90,87dB로 가장 높았으며, 선수(No. 1)에서 65,63,53dB로 가장 낮았다. 2. 학생 거주구역에서는 주기소음보다 통풍기나 에이콘의 가동소음이 주소음원을 이루었는데 통풍기를 가동하면 표박할때와 에이콘을 가동하면서 순항때를 비교하면, 출입구(No. 14)에서 85,69dB로 가장 높았고 학생실(No. 22)에서 45,40dB로 가장 낮았다. 3. 중앙부의 선원거주구역에서는 순항소음압이 예망소음압보다 2dBwjd도로 선원식당(No. 30)까지는 높게 나타났고, 급냉실(No. 31)로 부터는 반대로 낮게 측정 되었다. 또 이 구역에서는 출입문을 닫았을 때 선장실(No, 25)에서 13dB, 선원식당(No, 30)에서 3dB씩 낮아졌다. 4. 순항시 주기소음압은 Pitch $8^{\circ}$와 $12^{\circ}$때 103, 105dB 였는데, Pitch $8^{\circ}$로 예망시는 106dB로서 3dB의 증가를 보였다. 5. 선형과 기관이 같은 오대산호와 소음을 비교 하면 식당, 싸롱, 학생식에서 $4\~6dB$씩 낮았고 작업갑판상에서는 14dB나 높은 음압이였다.