• 한국소음진동공학회논문집
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• 제15권5호
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• pp.527-535
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• 2005

This paper explains a general coupling system in terms of the system parameters. impedance of a cavity or mobility of a structure. To easily access the mechanism of the structural-acoustic coupled system, a simple expression is derived. A general coupled equation is also derived of a general coupled problem constituted a flexible structure and an opening boundary in terms of vector and matrix notation, and is analyzed the coupling phenomena using the understanding acquired simple coupled system. The paper shows that the general coupled equation is expanded version of the simple coupled equation by some limiting checks. The paper also shows that the degree of coupling is proportioned to a stiffness of the acoustic system and a modal coupling coefficient, but is in inverse proportion to a mass of the structural system and the difference of the excitation frequency and resonant frequency of the acoustic or structural system.

• 한국소음진동공학회논문집
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• 제13권11호
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• pp.882-889
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• 2003

This paper presents the method for structure borne noise analysis of a flexible body in multibody system. The proposed method is the superposition method using the flexible multibody dynamic analysis and the finite element one. This method is executed in 3 steps. In the 1st step, time dependent quantities such as dynamic loads, modal coordinates and gross body motion of the flexible body are calculated through a flexible multibody dynamic analysis. And frequency response functions of those time dependent quantities are computed through Fourier transforms. In the 2nd step, acoustic pressure coefficients are obtained through structure-acoustic coupling analyses by the finite element method. In the final step, frequency responses of acoustic pressure at the acoustic nodes are recovered through linear superposition of frequency response functions with acoustic pressure coefficients. The accuracy of the proposed method is verified in the numerical example of a simple car model.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 춘계학술대회 논문집
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• pp.443-446
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• 2014

Recently the demand for natural gas as clean and safe energy due to concerns about global warming and interests in green ship is increasing. The dual fuel(DF) engine, one of environmentally friendly engines, is preferred for general merchant ships and power plants as well as LNG carriers. This is for the reasons of having higher efficiency and lower nitrogen and sulfur oxides emissions by operating on LNG fuel with a small amount of light fuel oil. In this study, the engine body vibration characteristics of 12V50DF in a generator set with engine-resilient-mounted, generator-rigid-mounted and flexible-coupling configuration are investigated through theoretical analysis and comprehensive vibration measurement. This analysis showed the dynamic behavior of engine excitation forces and seismic waves. And the suitable countermeasures for reducing vibration and safe operation are proposed.

• 한국정보디스플레이학회:학술대회논문집
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• 한국정보디스플레이학회 2008년도 International Meeting on Information Display
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• pp.75-77
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• 2008

Flexible electronics devices such as plastic display, thin film battery, membrane switch, organic memory for smart card applications will be presented. The performance and power consumption of various display technologies will be compared for OTP requirement in smart cards. Wireless power transmission by RF coupling through an antenna provides a potential power solution to smart cards. Finally, the general trend of smart card future developments will be discussed.

• 한국공작기계학회:학술대회논문집
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• 한국공작기계학회 2000년도 추계학술대회논문집 - 한국공작기계학회
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• pp.140-143
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• 2000

Motion control system using motor generally consists of 2 inertio system, motor inertio and load inertio linked with flexible coupling. In the case of direct drive motor control, the effect of coupling inertio decrease the precision performance. The study is about semiclosed control scheme of the system and experimental setup. To compensate the effect of coupling inertio, semiclosed control system by disturbance observer is employed. The simulation result is shown.

• 대한기계학회논문집A
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• 제21권6호
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• pp.896-906
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• 1997

The effect of duplicate flexible disks on the vibrational modes of a flexible rotor system is investigated by using an anlytical method based on the assumed modes method. The rotor model to be analyzed consists of duplicate disks on a flexible shaft. In modeling the system, centrifugal stiffening and disk flexibility effects are taken into account. To demonstrate the effectiveness of the method, a hard disk drive spindle system commonly used in personal computers and a simple flexible rotor system with two disks are selected as examples. In particular, the dynamic coupling between the vibrational modes of the shaft and the duplicate disks is investigated with the shaft rotational speed varied.

• 폴리머
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• 제33권6호
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• pp.525-529
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• 2009

우수한 성능의 2층 연성동박적층판(이하 FCCL)을 제조하기 위해서는 동박과 폴리이미드 사이에서 높은 접착력이 요구된다. 이를 위해 이종 재료로 인한 두 계면 사이의 접착력을 향상시키기 위해서는 일반적으로 기능성 실란커플링제가 사용된다. 본 연구에서는 압연동박과 폴리이미드 사이의 접착력 향상과 이미드화를 위한 고온의 열처리 조건에서도 안정한 새로운 형태의 실란커플링제를 합성하였다. 또한, 합성된 실란커플링제를 압연동박에 처리하였을 때, 표면처리제의 농도에 따른 표면변화를 관찰하였으며, 이로 인해 발생되는 접착력 변화를 확인하기 위해서 2층 FCCL을 제조하여 $90^{\circ}$ peel test를 통해 관찰하였다. 그리고, 두 종류의 폴리이미드를 이용한 FCCL에서 실란 커플링제가 접착력에 미치는 영향을 확인하였다.

• 폴리머
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• 제35권4호
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• pp.302-307
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• 2011

실란 커플링제의 가수분해를 통한 실란올의 형성과 올리고머 구조형성을 하는 중합반응은 2-FCCL의 표면처리 과정에서 계면 사이의 접착력에 영향을 준다. 본 연구에서는 설란 커플링제의 가수분해반응 속도를 비교하고 표면처리 후 동박의 표면 에너지로 인한 접착특정의 변화를 확인하였다. 특히 이성분계 살란 커플링제는 가수분해 반응속도 조절이 기능하며, 동박과 폴리이미드 사이에서 접착 프로모터로서 확실한 접착력 향상을 보였다. 압연동박 표면에 처리한 이성분계 실란 커플링제의 함량 변화에 띠라 접착력의 향상 정도가 다르게 나타났으며 반응속도 조절과 표면 에너지 평가를 통한 접착 특성을 분석해 접착력을 최대화시켰다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 춘계학술대회논문집E
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• pp.185-190
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• 2001

Rotating disks are used in various machines such as floppy disks, hard disk, turbines and circular sawblades. The problems of vibrations of rotating disks are important in improving these machines. Many investigators have dealt with these problem. Specially, vibrations of a rotating flexible disk taking into account the effect of air is difficult problem in simulation. The governing equation of a rotating flexible disk coupled to the surrounding fluid is investigated by a simple mathematical model. And several important parameters concerned with the stability of a rotating flexible disk are defined. Coupling strength between air and rotating flexible disk is proportional to square of disk radius directly and square root of the all of bending rigidity, disk density and thickness inversely. Lift-to-damping coefficient has relation to the onset of disk flutter.

• International Journal of Naval Architecture and Ocean Engineering
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• 제12권1호
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• pp.376-386
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• 2020

The aim of this study was to develop a new efficient strategy that uses the Vector form Intrinsic Finite-element (VFIFE) method to conduct the static and dynamic analyses of marine pipes. Nonlinear problems, such as large displacement, small strain, and contact and collision, can be analyzed using a unified calculation process in the VFIFE method according to the fundamental theories of point value description, path element, and reverse motion. This method enables analysis without the need to integrate the stiffness matrix of the structure, because only motion equations of particles established according to Newton's second law are required. These characteristics of the VFIFE facilitate the modeling and computation efficiencies in analyzing the nonlinear dynamic problem of flexible pipe with large deflections. In this study, a three-dimensional (3-D) dynamical model based on 3-D beam element was established according to the VFIFE method. The deep-sea flexible pipe was described by a set of spatial mass particles linked by 3-D beam element. The motion and configuration of the pipe are determined by these spatial particles. Based on this model, a simulation procedure to predict the 3-D dynamical behavior of flexible pipe was developed and verified. It was found that the spatial configuration and static internal force of the mining pipe can be obtained by calculating the stationary state of pipe motion. Using this simulation procedure, an analysis was conducted on the static and dynamic behaviors of the flexible mining pipe based on a 1000-m sea trial system. The results of the analysis proved that the VFIFE method can be efficiently applied to the static and dynamic analyses of marine pipes.