• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 춘계학술대회논문집
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• pp.648-655
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• 2005

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the Engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.291-296
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• 2007

This study presents the evaluation process for door module. Its objective evades the resonance generated at module plate due to the operation of window regulator motor. For this study, the design improvement process is composed of experimental methods having three steps. First step is modal analysis at door assembly status for acquisition of dynamic characteristics which are modal frequency and damping. Second step is a vibration experiment to get the test mode considered an efficiency of window regulator motor. Last step is a vibration measurement by the form of $6{\times}6$ array on module plate. A vibration measurement of 6x6 array form can be got to three analysis results which are a transfer path of vibration using cross correlation function, a vibration map using OA level and a contribution by frequency band using coherent output power spectrum on module plate. These results are applied to SDM(structural dynamic modification) for design improvement to get around the resonance on module plate by the excitation of window regulator motor.

• 전기학회논문지P
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• 제58권3호
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• pp.263-269
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• 2009

This paper describes comparative analysis results about the dynamic interaction of interconnected wind power system using the actual-size hardware simulator and the simulation model with PSCAD/EMTDC. The hardware simulator, which is composed of 2.0MVA induction motor with drive system and 1.5MW doubly-fed induction generator, was built and tested in Go-Chang Test Site of KEPCO for analyzing the dynamic interaction with the interconnected distribution system. The operation of hardware simulator was verified through comparative analysis between experimental results and simulation results obtained by simulation model with PSCAD/EMTDC. The developed hardware simulator and simulation model could be effectively used for analyzing the dynamic interaction, which has various phenomena depending on the wind variation and the network state of interconnected power system.

• 한국소음진동공학회논문집
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• 제17권11호
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• pp.1093-1101
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• 2007

This study presents the design improvement process for door module. Its objective evades the resonance generated at module plate due to the operation of window regulator motor. For this study, the design improvement process is composed of experimental methods having three steps. First step is modal analysis at door assembly status for acquisition of dynamic characteristics which are modal frequency and damping. Second step is a vibration experiment to get the test mode considered an efficiency of window regulator motor. Last step is a vibration measurement by the form of $6{\times}6$ array on module plate. A vibration measurement of $6{\times}6$ array form can be got to three analysis results which are a transfer path of vibration using cross correlation function, a vibration map using OA level and a contribution by frequency band using coherent output power spectrum on module plate. These results are applied to SDM(structural dynamic modification) for design improvement to get around the resonance on module plate by the excitation of window regulator motor.

• 한국추진공학회지
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• 제15권1호
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• pp.45-54
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• 2011

액체로켓엔진 시스템에 대한 동특성 예측 프로그램을 작성하였다. 이 프로그램을 통해 얻은 펌프 시동 시 압력 및 유량 변화 결과를 수류시험장치를 구축하여 실험적으로 검증하였다. 수류시험장치는 실제 개방형 액체로켓엔진 추진제 공급 계통에서 구성품의 형태와 배치위치, 가스발생기와 주연소실로 분기되는 유량비를 기준으로 모사되었다. 동특성 예측 프로그램의 작성을 위해 구성품별 동특성 모델링을 수행하고 엔진 시스템을 기준으로 각 모델링을 순차적으로 통합하였다. 예측 프로그램에 구성품의 동특성 파라미터를 측정 반영하였고 천이 작동 상태에서 엔진 시스템 내의 작동 파라미터 변화 결과를 실험적으로 측정하고 비교 분석하였다.

• International Journal of Naval Architecture and Ocean Engineering
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• 제8권5호
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• pp.511-518
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• 2016

The dynamic positioning system (DPS) maintains an offshore vessel's position and heading under various environmental conditions by using its own thrust. DPS is regarded as one of the most important systems in offshore vessels. So, efficient operation and maintenance of the DPS are important issues. To monitor the DPS, it is necessary to define an appropriate key performance indicator (KPI) that can express the condition of the DPS from the perspective of operational efficiency and maintenance. In this study, a new KPI for the DPS is proposed considering the efficiency of the machinery and controller, the energy efficiency, and the environmental conditions in which the DPS is operated. The KPI is defined as a function of control deviation, energy consumption, and environmental load. A normalization factor is used to normalize the effect of environmental load on the KPI. The KPI value is calculated from DPS simulation and model test data. The possibility of applying the KPI to monitoring of DPS condition is discussed by comparing the values. The result indicates the feasibility of the new KPI.

• 한국소음진동공학회논문집
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• 제16권4호
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• pp.329-338
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• 2006

The resilient mounts of a diesel engine installed onboard a ship should be designed for both static and dynamic loads. If possible, the resonance frequencies of the six rigid body modes of the installation and the flexible modes of the engine support structure should not lie within the engine operation range. In this paper a design criterion is proposed to evaluate an isolation system which involves the summation of dynamic forces transmitted through the resilient mounts and elastic potential energy index stored in the mounts. A case study is also presented in which a diesel engine generator, which had an elastic foundation and was mounted in a 5500 TEU container vessel, was studied both theoretically and experimentally. The theoretical analysis of the test model was performed by using a single mass 6 degree of freedom system. Actual measurements of mechanical vibration of the engine and its foundation onboard were carried out, which showed the importance of including the flexibility of the engine support structure in the mode.

• 한국전기전자재료학회논문지
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• 제22권10호
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• pp.864-869
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• 2009

The measurement of contact wire uplift in electric railways is one of the most important test parameters to accepting the maximum permitted speed of new electric vehicles and pantographs. The contact wire uplift can be measured over short periods when the pantograph passes monitoring stations. In this paper, a high-speed image measurement system and its image processing method are being developed to evaluate dynamic uplift of overhead contact wires caused by pantograph contact forces of Korea Tilting Train eXpress (TTX) and Korea Train eXpress (KTX). The image measurement system was implemented utilizing a high-speed CMOS (Complementary Metal Oxide Semiconductor) camera and gigabit ethernet LAN. Unlike previous systems, the uplift measurement system using high speed camera is installed on the side of the rail, making maintenance convenient. On-field verification of the uplift measurement system for overhead contact wire using high speed camera was conducted by measuring uplift of the TTX followed by operation speeds at the Honam conventional line and high-speed railway line. The proposed high-speed image measurement system to evaluate dynamic uplift of overhead contact wires shows promising on-field applications for high speed trains such as KTX and TTX.

• 한국소음진동공학회논문집
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• 제13권6호
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• pp.474-483
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• 2003

In this study, the dynamic characteristics of a catenary system and pantograph supplying electrical power to high-speed trains are investigated. One of the most important issues accompanied by increasing the speed of high-speed rail is stabilization of current collection. To stabilize current collection, it is necessary the contact force between the catenary and the pantograph to be kept continuous without loss of contact. The analytical model of a catenary and a pantograph is constructed to simulate the behavior of an actual system. The analysis of the catenary based on the Finite Element Method (FEM) is performed to develop a catenary model suitable for high speed operation. The reliability of the models is verified by the comparison of the excitation test with Fast Fourier Transform (FFT) data of the actual system. The static deflection of the catenary, stiffness variation in contact lines, dynamic response of the catenary undergoing constant moving load, contact force, and each state of the pantograph model were calculated. It is confirmed that a catenary and pantograph model are necessary for studying the dynamic behavior of the pantograph system.

• 한국군사과학기술학회지
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• 제25권1호
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• pp.1-8
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• 2022

Electronic equipment mounted on military vehicles is exposed to external shocks and vibrations. This causes problems in tactical operation and also causes cost loss in equipment maintenance. Therefore, to optimize the test standards for military vehicles with vibration, dynamic characteristics should be analyzed and standardized through actual driving tests. In this paper, the internal structure of 2.5tons military vehicle is designed in the form of a drawer and lathe, and the dynamic characteristics are identified by experiment, and the design is proposed.