• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 1995.10a
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• pp.249-253
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• 1995

본 연구에서는 잠재적 응용성이 큰 ER유체와 압전필름을 액튜에이터로 하는 하이브리드형 지능구조물을 제안한 후 능동 진동제어를 실시하였다. 먼저 중공(hollow)의 샌드위치 형태 복합재료(glass/epoxy)보에 ER유체와 압전필름을 각각 삽입과 접착을 하여 하이브리드형 지능구조물을 제작하였다. 그리고 각 매체의 액튜에이팅 특성을 고려하여, ER유체 액튜에이터(ERFA)는 전장부하 함수로 도출되는 구조물의 주파수응답을 특징으로 하였고, 압전필름 액튜에이터(PFA)는 신경 슬라이딩 모드 제어기 (neuro sliding mode controller : NSC)를 적용하였다. 이 두 액튜에이터가 동시에 작동하는 능동 진동제어계를 실험적으로 구현한 후 과도응답과 강제 응답에 대한 진동제어 성능을 단일 액튜에이터 작동시와 비교 고찰하여 제시된 하이브리드 액튜에이팅의 효과를 입증하였다.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2000.06a
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• pp.1823-1828
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• 2000

Power transformers, air-intakes, stacks in a combined thermal power plant are the main noise sources. Power transformer noise among them has being get a target of public complaint due to 480Hz component of its pure tone. The source is mainly magnetostrictive vibration of the transformer core. The first countermeasures was installing sound barrier on the front of transformer. However, 500Hz, center of the frequency is not reduced. This paper includes the measurements of noise level at the near resident apartment, the identification of noise transfer and the countermeasures for noise sources. Cavity resonance type of noise reduction devices was installed on enclosuring wall of transformers. As a result, the noise level from transformer is reduced about 3dB.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.461-466
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• 2012

Customers want to have more convenient and comfortable vehicle. Motor-on-caliper EPB(Electrical Parking Brake) System is one of the new systems for customer's convenience. It is applied for Midsize vehicle for reducing weight/price compared to cable puller type EPB. In this paper we studied sound quality improvement of motor-on-caliper EPB system. We developed the sound quality index and suggested the interior sound quality target value. To meet the target value cascading target was also suggested. EPB motor vibration level & sound radiation level, vibro-acoustic transfer function level from EPB to interior was defined. To find out effective way of sound quality improvement and find cascading target, TPA(Transfer Path Analysis) was carried out.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.907-910
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• 2012

Since the inner barrel assembly of the Advanced Power Reactor 1400 reactor vessel is a new design feature introduced instead of CEA(control element assembly) shroud assembly, the inner barrel assembly can be a significant object of structural integrity assessment. This paper covers the structural responses of top plate, which is a component of the inner barrel assembly, against the deterministic hydraulic load induced by pump pulsation and the random hydraulic load induced by turbulence of coolant. The top plate responds to the deterministic hydraulic load more than to the random hydraulic load and shows enough structural integrity. The results of this paper will be important basis for the selection of instruments and measurement location.

• Proceedings of the KSME Conference
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• 2003.11a
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• pp.1268-1273
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• 2003

This paper presents a case history of piping failures on power plant. The root cause of the failure was defined to set the optimal countermeasures. The failure comes from transient vibration and the 1st stress increased at the hydraulic oil supply system of control valves for high pressure steam turbine.

• Proceedings of the KIPE Conference
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• 1998.07a
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• pp.58-62
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• 1998

In the industrial motor drive systems, a torsional vibration is often generated because of the elastic elements in torque transmission. One of general methods for the system is H$\infty$ controller to suppress the torsional vibration and reject the torque disturbance. vibration and reject the torque disturbance. Moreover, the two-degrees-of-freedom controller, which includes the H$\infty$ controller, is designed in order to improve the command following property. In this paper, we propose a new H$\infty$ controller with partial state feedback. This method having simple structure satisfies with the fast command following property and the attenuation of disturbances and vibrations simultaneously, just like the complicated TDOF H$\infty$ controller

• Explosives and Blasting
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• v.27 no.1
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• pp.53-61
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• 2009

R.O.K's explosive manufacturing source was first black powder (B.P) introduced into Korea Dynasty from China. In 1890, black powder was first used for mining blasting in Masan. Nowadays, a vibration control blasting method using the emulsion explosive has been applid to explosive demolition of building structure, subway and road construction sites. In December, 2006, Korean Government and professional society (KSEE) established the blasting guidelines of Modern Vibration Controlled Blasting Method (MVCBM) which is an unprecedented in the world.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.17 no.12
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• pp.1170-1178
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• 2007

Repeated hardware tests and tuning, investing cost and time, are usually required to assure a satisfactory performance of the suspension seat. In this study, an EILS(ECU-in-the-loop) method was proposed to develop a controller for a semi-active suspension seat with a MR(magneto-rheological) damper. EILS system was developed using a real-time seat dynamics model communicating with ECU hardwares under a closed loop environment utilizing Matlab/Simulink and xPC $TargetBox^{TM}$. A sky-hook based control algorithm with optimized damping coefficients was verified to reduce the energy consumption and to improve the vibration response performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.337-342
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• 2011

This paper presents the performance of a full vehicle MR suspension system at different tire pressure. The pressure of tire is related to tire stiffness, which is significantly affects the performance of suspension system. Therefore, in this research, the effectiveness of tire pressure on full vehicle MR suspension is evaluated. As a first step, the characteristic of tire with respect to pressure is experimentally tested and modeled. After that, the governing equation of MR damper and full vehicle MR suspension system are derived. The skyhook controller is implemented and the vibration control performance of full vehicle MR suspension is evaluated via simulation with respect to the tire pressure.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2011.10a
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• pp.343-348
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• 2011

This paper presents ride comfort characteristics of a quarter-vehicle magneto-rheological (MR) suspension system with respect to different tire pressure. As a first step, controllable MR damper is designed and modeled based on both the optimized damping force levels and mechanical dimensions required for a commercial full-size passenger vehicle. Then, a quarter-vehicle suspension system consisting of sprung mass, spring, tire and the MR damper is constructed. After deriving the equations of the motion for the proposed quarter-vehicle MR suspension system, vertical tire stiffness with respect to different tire pressure is experimentally identified. The skyhook controller is then implemented for the realization of the quarter-vehicle MR suspension system. Finally, the ride comfort analysis with respect to different tire pressure is undertaken in time domain. In addition, a comparative result between controlled and uncontrolled is provided by presenting vertical RMS displacement.