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REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
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Transactions of the Korean Society for Noise and Vibration Engineering
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Journal DOI :
The Korean Society for Noise and Vibration Engineering
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Volume & Issues
Volume 15, Issue 12 - Dec 2005
Volume 15, Issue 11 - Nov 2005
Volume 15, Issue 10 - Oct 2005
Volume 15, Issue 9 - Sep 2005
Volume 15, Issue 8 - Aug 2005
Volume 15, Issue 7 - Jul 2005
Volume 15, Issue 6 - Jun 2005
Volume 15, Issue 5 - May 2005
Volume 15, Issue 4 - Apr 2005
Volume 15, Issue 3 - Mar 2005
Volume 15, Issue 2 - Feb 2005
Volume 15, Issue 1 - Jan 2005
Selecting the target year
Monitoring of Beam-column Joint Using Optical Fiber Sensors
Kim, Ki-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 3~11
DOI : 10.5050/KSNVN.2005.15.1.003
For monitoring of the civil and building structure, optical fiber sensors are very convenient. The fiber sensors are very small and do not disturb the structural properties. They also have several merits such as electro-magnetic immunity, long signal transmission, good accuracy and multiplexibility in one sensor line. Strain measurement technologies with fiber optic sensors have been investigated as a part of smart structure. In this paper, we investigated the possibilities of fiber optic sensor application to the monitoring of beam-column joints of structures. We expect that the fiber optic sensors replace electrical strain gauges. The commercial electric strain gauges show good stability and dominate the strain measurement market. However, they lack durability and long term stability for continuous monitoring of the structures. In order to apply the strain gauges, we only have to attach them to the surfaces of the structures. In this paper, we investigate the possibility of using fiber optic Bragg grating sensors to joint structure. The sensors show nice response to the structural behavior of the joint.
Dynamic Characteristic Analysis and Position Control for High Density Optical Head Using Bimorph PZT
Park, Tae-Wook ; Park, No-Cheol ; Yang, Hyun-Seok ; Park, Young-Pil ; Kwon, Young-Ki ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 12~19
DOI : 10.5050/KSNVN.2005.15.1.012
This paper proposed a dual actuator using Bimorph PZT for information storage device based on prove array NSOM(near-field scanning optical microscopy). The gap between the media and the optical head should be maintained within the optical tolerance. Therefore, a new actuator having high sensitivity is required. Bimorph PZT, which has fast access time and high sensitivity characteristic, is suitable for this precise actuating system. This paper is focused on derivation of mathematical model of dual Bimorph PZT actuator and control algorithm. Hamilton`s principle was used for mathematical model. The model is verified by FEA(finite element analysis), and compared with experimental results. Different control algorithms were used for two Bimorph PZT actuating same direction and opposite direction. The gap between recording media and optical head was controlled within 20nm in experiment.
Study on Uncertainty Factors of Head Vibration Measurements
Cheung, Wan-Sup ; Kim, Young-Tae ; Ryu, Je-Dam ; Hong, Dong-Pyo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 20~28
DOI : 10.5050/KSNVN.2005.15.1.020
This paper addresses uncertainty issues encountered recently in measuring head vibration using the conventional 6-axis or 9-axis bite-bar model. Those conventional bite-bar models are shown to present insufficient information to evaluate a generalized motion of head vibration. In order to overcome such limit, a new theoretical measurement model that consists of four 3-axis linear accelerometers is suggested. It is shown to enable the measurement of three angular acceleration components and six second-order angular velocity-dependent terms. Those nine angular motion-related ones, in addition to the three linear acceleration terms at the origin, are found to make it possible to evaluate the generalized head vibration for a given position. To examine the feasibility of the proposed method, a newly designed 12-axis bite-bar was developed. Detailed experimental results obtained from the developed 12-axis bite-bar are demonstrated in this paper. They illustrate that the popular 6-axis bite-bar model yield about
relative measurement uncertainty for the pitch component of head vibration,
relative measurement uncertainty for the roll and yaw components of head vibration, respectively. Furthermore, this paper proposes other uncertainty factors to be considered in the future.
Pull-in Behavior Analysis in Optical Disk Drive Using Phase Plane and Evaluations for Effecting Parameters of it
Choi, Jin-Young ; Park, Tae-Wook ; Yang, Hyunseok ; Park, No-Cheol ; Park, Young-Pil ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 29~38
DOI : 10.5050/KSNVN.2005.15.1.029
The track pull-in behavior analysis in an optical disk drive (ODD) using plane phase and the evaluations for effecting parameters of it are discussed. Track pull-in, track capture procedure to do track following control, is a key factor to increase data transfer rate. First, the relative velocity between the beam spot of an optical pick-up and the target track of an optical disk is analyzed during the track pull-in procedure. In this process, it is showed that the track error signal has nonlinear characteristics which are depending on the time. Second, Runge-Kutta method to solve the nonlinear equation is applied to find the track pull-in behavior, and some optimal parameters to get stable and fast pull-in condition are obtained. Then, the phase plane analysis for track pull-in procedure is presented. Finally, some comments for the simulated results are discussed briefly.
Experimental Study on the Whirling, Tilting and Flying Motion of the FDB Spindle System of a 3.5` HDD
Oh, S.H. ; Lee, S.H. ; Jang, G.H. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 39~45
DOI : 10.5050/KSNVN.2005.15.1.039
This research develops an experimental method to measure the motion of a FDB spindle system with a 3.5` disk by using three capacitance probes fixed on the xyz-micrometers, and it shows that a FDB spindle system has the whirling, flying and tilting motion. It also shows that the whirling, flying and tilting motion converge very quickly to the steady state at the same time when the rotor reaches the steady-state speed. However, they are quite large even at the steady state when they are compared with the 10nm flying height of a magnetic head. For the FDB spindle system used in this experiment, the whirl radius and the peak-to-peak variation of flying height and tilting angle at the steady-state speed of 7,200rpm are 0.675m, 30nm and
, respectively, so that the radial motion of the FDB spindle system exceeds a track pitch of a 3.5` HDD with 90,000 TPI.
Application of Perturbation Method to the Dynamic Analysis of Free-free Beam
Kwak, Moon-K ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 46~52
DOI : 10.5050/KSNVN.2005.15.1.046
This paper is concerned with the application of perturbation method to the dynamic analysis of free-free beam. In general, the rigid-body motions and elastic vibrations are analyzed separately. However, the rigid-body motions cause vibrations and elastic vibrations also affect rigid-body motions in turn, which indicates that the rigid-body motions and elastic vibrations are coupled in nature. The resulting equations of motion are hybrid and nonlinear. We can discretize the equations of motion by means of admissible functions but still we have to cope with nonlinear equations. In this paper, we propose the use of perturbation method to the coupled equations of motion. The resulting equations consist of zero-order equations of motion which depict the rigid-body motions and first-order equations of motion which depict the perturbed rigid-body motions and elastic vibrations. Numerical results show the efficacy of the proposed method.
Application of Lamb Waves and Probabilistic Neural Networks for Health Monitoring of Joint Steel Structures
Park, Seung-Hee ; Lee, Jong-Jae ; Yun, Chung-Bang ; Roh, Yongrae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 53~62
DOI : 10.5050/KSNVN.2005.15.1.053
This study presents the NDE (non-destructive evaluation) technique for detecting the loosened bolts on joint steel structures on the basis of TOF (time of flight) and amplitudes of Lamb waves. Probabilistic neural network (PNN) technique which is an effective tool for pattern classification problem was applied to the damage estimation using PZT induced Lamb waves. Two kinds of damages were introduced by dominant damages (DD) which mean loosened bolts within the Lamb waves beam width and minor damages (MD) which mean loosened bolts out of the Lamb waves beam width. They were investigated for the establishment of the optimal decision boundaries which divide each damage class`s region including the intact class. In this study, the applicability of the probabilistic neural networks was identified through the test results for the damage cases within and out of wave beam path. It has been found that the present methods are very efficient and reasonable in predicting the loosened bolts on the joint steel structures probabilistically.
Structural Vibration Analysis for a Composite Smart UAV Considering Dynamic Hub-loads of the Tilt-rotor
Kim, Dong-Hyun ; Jung, Se-Un ; Koo, Kyo-Nam ; Kim, Sung-Jun ; Kim, Sung-Chan ; Lee, Ju-Young ; Choi, Ik-Hyeon ; Lee, Jung-Jin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 63~71
DOI : 10.5050/KSNVN.2005.15.1.063
In this study, structural vibration analyses of a composite smart unmanned aerial vehicle (UAV) have been conducted considering dynamic hub-loads of tilt-rotor. Practical computational structural dynamics technique based on the finite element method is applied using MSC/NASTRAN. The present smart UAV(TR-S2) structural model is constructed as full 3D configurations with both the helicopter flight mode and the airplane flight mode. Modal based transient response and frequency response analyses are used to efficiently investigate vibration characteristics of structure and installed electronic equipments. It is typically shown that the helicopter flight mode with the 90-deg tilting angle is the most critical case for the induced vibration of installed electronic equipments in the front.
Squeal Noise Analysis and Reduction of Drum Brake Using Component Mode Synthesis
Kim, Jin-Ho ; Bae, Byung-Ju ; Lee, Shi-Bok ; Kim, Tae-Jong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 72~80
DOI : 10.5050/KSNVN.2005.15.1.072
Recent studies have dealt with brake squeal in terms of the coupled vibration of brake component parts. In this paper, we assemble the mode models derived from FE analysis of the individual components of the drum brake system into the system model by considering the friction interaction of the lining and drum at the interface. The validity of the component models are backed up by the experimental confirmation work. By scrutinizing the real parts of the complex eigen-values of the system, the unstable modes, which may be strong candidate sources of squeal noise, are identified. Mode participation factors are calculated to examine the modal coupling mechanism. The model predictions for the unstable frequencies pointed well the actual squeal noise frequencies measured through field test. Sensitivity analysis is also performed to identify parametric dependency trend of the unstable modes, which would indicate the direction for the squeal noise reduction design. Finally, reduction of the squeal noise tendency through shape modification is tried.
Damage Detection in a Plate Using an Orientation-adjustable Magnetostrictive Transducer
Cho, Seung-Hyun ; Lee, Ju-Seung ; Sun, Kyung-Ho ; Kim, Yoon-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 81~86
DOI : 10.5050/KSNVN.2005.15.1.081
In this work, we propose a new ultrasonic damage inspection method in plate structures. The proposed method employs an OPMT(orientation-adjustable patch-type magnetostrictive transducer) in order to make the ultrasonic waves directed to a specific target point. For experiments, virtual grid points were set up at every 50 mm in an aluminum plate and two OPMTs were used for inspection. If there exists a crack in a plate, the reflected Lamb wave from the crack is measured in addition to the direct waves from the transmitting transducer to the receiving transducer.
Finite Element Analysis of a Coupled Hydrodynamic Journal and Thrust Bearing in a Computer Hard Disk Drive
Kim, Hakwoon ; Lee, Sanghoon ; Jang, Gunhee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 87~95
DOI : 10.5050/KSNVN.2005.15.1.087
This paper proposes a method to calculate the characteristics of a coupled hydrodynamic journal and thrust bearing of a HDD spindle motor. The governing equations for the journal and thrust bearings are the two dimensional Reynolds equations in
planes, respectively. Finite element method is appropriately applied to analyze the coupled journal and thrust bearing by satisfying the continuity of mass and pressure at the interface between the journal and thrust bearings. The pressure in a coupled bearing is calculated by applying the Reynolds boundary condition and compared with that by using the Half-Sommerfeld boundary condition. The static characteristics are obtained by integrating the pressure along the fluid film. The flying height of spindle motor is measured to verify the proposed analytical result. This research shows that the proposed method can describe HDB in a HDD system more accurately and realistically than the separate analysis of a journal or thrust bearing.
Coupled Vibration Analysis of Cylindrical Fluid-storage Tanks with a Baffle
Kim, Young-Wann ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 96~104
DOI : 10.5050/KSNVN.2005.15.1.096
The coupled vibration characteristics for the fluid-structure interaction systems are investigated through the finite element method. The present paper is focused on vibration characteristics of the cylindrical fluid-storage tank with a baffle. The tank is partially filled with an inviscid and irrotational fluid having a free surface. A baffle is assumed here to have the shape of a thin annular plate and a conical shell, attached to the cylindrical tank and positioned below the fluid surface. The liquid domain is limited by a rigid flat bottom. As the effect of free surface waves is taken into account in the analysis, the bulging and sloshing modes are studied. To demonstrate the validity of present results, they are compared with the published ones. The effect of positions and inner-to-outer radius ratio of annular baffle and setting angles of conical baffle on coupled vibration characteristics is investigated.
Active Vibration Control of Smart Structure Using Pulse Width Modulation
Kwak, Moon K. ; Kim, Ki-Young ; Bang, Se-Yoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 105~111
DOI : 10.5050/KSNVN.2005.15.1.105
This paper is concerned with the active vibration control of smart structure using actuator signal made of pulse width modulation. The pulse width modulation has been used in motor control, where the amount of energy fed into the motor is controlled by the pulse width instead of applied voltage. The advantage of using the pulse width modulation is that analog signal can be replaced by the digital signal so that we can reduce system costs and power consumption. The effect of pulse width modulation on the vibration response was investigated in this study and the valid transformation rule was found. Then, the pulse width modulation was realized using a microprocessor and electronic circuit. The active vibration suppression was carried out by combining the positive position feedback controller and the pulse width modulation. The experimental result shows that we can replace an expensive amplifier with a pulse width modulation system thus reducing the system cost. The result also shows that the active vibration control can be achieved by the pulse width modulation technique.
Investigation of Efficiency of Starting Iteration Vectors for Calculating Natural Modes
Kim, Byoung-Wan ; Kyoung, Jo-Hyun ; Hong, Sa-Young ; Cho, Seok-Kyu ; Lee, In-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 15, issue 1, 2005, Pages 112~117
DOI : 10.5050/KSNVN.2005.15.1.112
Two modified versions of subspace iteration method using accelerated starting vectors are proposed to efficiently calculate free vibration modes of structures. Proposed methods employ accelerated Lanczos vectors as starting iteration vectors in order to accelerate the convergence of the subspace iteration method. Proposed methods are divided into two forms according to the number of starting vectors. The first method composes 2p starting vectors when the number of required modes is p and the second method uses 1.5p starting vectors. To investigate the efficiency of proposed methods, two numerical examples are presented.