• 한국지진공학회:학술대회논문집
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• 한국지진공학회 2002년도 추계 학술발표회 논문집
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• pp.371-378
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• 2002

The design concepts using vibration reduction techniques, or structural control, have been proposed recently to protect infrastructure against earthquakes. The magnetorheological(MR) fluid damper is one of the most promising new devices for structural vibration reduction because of its mechanical simplicity, high dynamic range, low power requirement, large force capacity and robustness. In this study, the seismic performance of MR devices are compared with that of NZ systems as an attempt to provide some data for improving seismic design techniques applied to structures. For nonlinear time domain analysis of a base isolation system, a six-story building model is considered as a numerical example. The ground acceleration data of El Centre 1940, Mexico City 1985 and Kobe 1995 earthquakes are used as seismic excitations. The results show that MR damper systems for outperform NZ systems in wide-ranging seismic excitations with respect to intensity and period characteristics.

• 한국소음진동공학회논문집
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• 제17권6호
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• pp.484-490
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• 2007

A reciprocating compressor used in domestic refrigerators can be subjected to many different forms of shock. These shocks are usually experienced during transporting the products from a manufacturer to customers. The hermetic structure of this kind of compressor makes it difficult to conduct drop tests for identifying the failure mechanism and their drop behaviors. The drop/impact simulation for a reciprocating compressor has been carried out with the explicit code LS-DYNA and its validation has been experimentally verified. Simulation results are in good agreement with those of drop test. The present method of drop/impact simulation provides an efficient and powerful solution to improve the design quality and reduce the design period.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.247-251
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• 2001

Nowadays, base isolation systems such as lead-rubber bearing, elastomer bearing and sliding bearing have been installed to the various structures to prevent the disaster from seismic. The performance of base isolation system have been well proved by model-scale experiments and numerical analysis. However. the seismic response data measured at real large base-isolated structures is still insufficient. This paper presents a seismic monitoring system, acquiring real-time acceleration signals up to 32 channels, displaying time history and spectrum of the signals, storing the acquired data at a PC hard disk, and replaying the saved data. Moreover, the system can be operated without any limitation for monitoring period by automatic management of stored data file. The developed system has been installed at a real base-isolated building using lead-rubber bearings and we expect its seismic response data with ground motion signal can be well licquired in case of earthquake occurrence.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 I
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• pp.219-224
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• 2001

An accurate tip position control of a single-link flexible manipulator subjected to torque disturbance is achieved by utilizing so called sliding mode controller with disturbance estimation (SMCDE). After formulating the governing equation of motion in the state 1pace representation, a stable sliding surface is designed via the LQR method. The SMCDE is then synthesized by integrating equivalent sliding mode controller with the disturbance estimator which is featured by an integrated average value of the imposed disturbance over a certain sampling period. The regulating tip motion of the flexible manipulator is evaluated by employing the proposed SMCDE.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.193-196
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• 2014

Experimantal evaluation of an energy storage device with high rotational speed to store regenerative energy which might be generated during the braking period of the trains is presented. The proposed ESS is small scale model and has 5kW output power, high rotational speed. In general railway trains generate regenerative energy for 10-20 sec when the train brakes and also high traction energy is needed for very short moment (10 sec) when the train increases the traction force. Considering such characteristics of the railway system energy storage device for the railway should have very fast response property. Among the various energy storage devices flywheel energy storage system has the fastest response property, which means that flywheel ESS is the most suitable for the railway system.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.60-65
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• 2003

In this study, for estimating responses of a controlled structure and determining the maximum control force of velocity-dependent damping devices, three estimation models such as Fourier envelope convex model, probability model, and Newmark design spectrum are used. For this purpose, a procedure proposed by Gupta (1990) for estimating spectral velocity using pseudo-spectral velocity which is given by the estimation models is used and modified to consider the effects of increased damping ratio by the damping device. Time history results indicate that Newmark design spectrum gives the best estimation of maximum control force for over all period structures.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2013년도 추계학술대회 논문집
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• pp.854-855
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• 2013

As an unique acoustic characteristic of a Korean bell. beat phenomenon is a periodic repetition of strong and weak sounds. Beat sounds good when it is clear and it has a proper period, however, it is not easy to satisfy these two conditions simultaneously. In this study, we propose a beat tuning method to satisfy these two conditions, by using an equivalent bell model. First, we construct an equivalent bell which has the same beat property with the 1st beat of a real bell and we investigate the change of mode pair by finite element analysis, when thickness of the bell is locally decreased at $22.5^{\circ}$ from the striking point. From the analysis result, minimum thickness reduction amount is determined to make a clear and strong beat.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.647-653
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• 2009

Taguchi parameter design is an approach to reducing performance variation of quality characteristic value in products and processes. Taguchi has used SN (Signal to Noise) ratio to achieve the appropriate set of operating conditions where variability around target is low in the Taguchi parameter design. This paper describes the prediction technique of vehicle performance using parameter analysis to reduce man hour and test development period as well as to achieve stable NVH performance. Design engineer could efficiently decide the design variable using parameter analysis database in early design stage. These improvements can reduce the time needed to develop better vehicles.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.84-87
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• 2005

This study is aimed to compare the insertion losses of periodically folded barriers which have same folded width, depth and period of arrangement but different direction of arrangement. One is vortical to the roadside and another is parallel. The pressure levels and the insertion losses at the receiving points behind finite length barriers are measured in an anechoic room by scale model test. The measured insertion losses are compared with calculated insertion losses by 3D BEM models.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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• pp.138-140
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• 2014

The image quality of the color laser printer is highly related with the motion quality of actuators. However, the high precision system requires high production costs in general. The proposed design method in this paper improves image quality without increasing production costs. Using the synchronization method, time gap between exposure and transfer in organic photo conductive (OPC) drum and the period of driving gear revolution are synchronized. The proposed method is verified by computer simulations and experiment, and showed by printed images.