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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 20, Issue 12 - Dec 2010
Volume 20, Issue 11 - Nov 2010
Volume 20, Issue 10 - Oct 2010
Volume 20, Issue 9 - Sep 2010
Volume 20, Issue 8 - Aug 2010
Volume 20, Issue 7 - Jul 2010
Volume 20, Issue 6 - Jun 2010
Volume 20, Issue 5 - May 2010
Volume 20, Issue 4 - Apr 2010
Volume 20, Issue 3 - Mar 2010
Volume 20, Issue 2 - Feb 2010
Volume 20, Issue 1 - Jan 2010
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Finite Element Analysis of a Particle Manipulation System Using Ultrasonic Standing Wave
Cho, Seung-Hyun ; Park, Jae-Ha ; Ahn, Bong-Young ; Kim, Ki-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 3~9
DOI : 10.5050/KSNVE.2010.20.1.003
Micro particles in fluid can be manipulated by using ultrasonic standing wave since the ultrasound makes particles move by means of its acoustic radiation force. This work concerns the micro particle manipulation system using ultrasonic standing wave which consists of a microchannel, a reflector, and an ultrasonic transduer. In the present system, the effects of the structural elements should be carefully considered to comprehend the system and find the optimal operational condition. In this investigation, finite element analysis was employed to analyze the system. Some interesting characteristics on the reflector thickness, the channel width, and the operational frequency were observed. Several experimental results were compared with the analytic results. Consequently, this work solidifies the importance of those system parameters and reveals the possibility of various applications of the particle manipulation using ultrasonic standing wave.
Vibration Analysis of Rotating Blades with the Cross Section Taper Considering the Pre-twist Angle and the Setting Angle
Lee, Jun-Hee ; Yoo, Hong-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 10~21
DOI : 10.5050/KSNVE.2010.20.1.010
Equations of chordwise and flapwise bending motions for the vibration analysis of rotating pre-twisted blades having tapered cross section and setting angle are derived by using hybrid deformation variable modeling. The two motions are couples to each other due to the pre-twisted angle of the beam cross section. The derived equations are transformed into dimensionless forms in which dimensionless parameters are identified. The effects of the dimensionless parameters on the modal characteristics of rotating pre-twisted blades having tapered cross section and orientation angle are investigated. The eigenvalue loci veering phenomena are also investigated and discussed in this work.
Design of Friction Dampers for Seismic Response Control of a SDOF Building
Min, Kyung-Won ; Seong, Ji-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 22~28
DOI : 10.5050/KSNVE.2010.20.1.022
Approximate analysis for a building installed with a friction damper is performed to get insight of its dynamic behavior. Energy balance equation is used to have a closed analytical form solution of dynamic magnification factor(DMF). It is found out that DMF is dependent on friction force ratio and resonance frequency. Approximation of DMF and equivalent damping ratio of a friction damper is proposed with such assumption that the building with a friction damper shows harmonic steady-state response and narrow banded response behavior near resonance frequency. Linear transfer function from input external force to output building displacement is suggested from the simplified DMF equation. Root mean square of a building displacement is derived under earthquake-like random excitation. Finally, design procedure of a friction damper is proposed by finding friction force corresponding to target control ratio. Numerical analysis is carried out to verify the proposed design procedure.
Vibration Analysis for the L-1 Stage Bladed-disk of a LP Steam Turbine
Lee, Doo-Young ; Bae, Yong-Chae ; Kim, Hee-Soo ; Lee, Yook-Ryun ; Kim, Doo-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 29~35
DOI : 10.5050/KSNVE.2010.20.1.029
This paper studies causes of the L-1 blade damage of a low pressure turbine, which was found during the scheduled maintenance, in 500 MW fossil power plants. Many failures of turbine blades are caused by the coupling of aerodynamic forcing with bladed-disk vibration characteristics. In this study the coupled vibration characteristics of the L-1 turbine bladed-disk in a fossil power plant is shown for the purpose of identifying the root cause of the damage and confirming equipment integrity. First, analytic and experimental modal analysis for the bladed-disk at zero rpm as well as a single blade were performed and analyzed in order to verify the finite element model, and then steady stresses, natural frequencies and corresponding mode shapes, dynamic stresses were calculated for the bladed-disk under operation. Centrifugal force and steady steam force were considered in calculation of steady and dynamic stress. The proximity of modes to sources of excitation was assessed by means of an interference diagram to examine resonances. In addition, fatigue analysis was done for the dangerous modes of operation by a local strain approach. It is expected that these dynamic characteristics will be used effectively to identify the root causes of blade failures and to perform prompt maintenance.
Dynamic Analysis of the Small-size Gas Turbine Engine Rotor Using Commercial S/W and Its Limitations
Chung, Hyuk-Jin ; Lee, Chong-Won ; Hong, Seong-Wook ; Yoo, Tae-Gyu ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 36~44
DOI : 10.5050/KSNVE.2010.20.1.036
The accurate prediction of dynamic characteristics of high speed rotors, such as gas turbines, is important to avoid the possibility of operating the machinery near the critical speeds or unstable speed regions. However, the dynamic analysis methods and softwares for gas turbines have been developed in the process of producing many gas turbines by manufacturers and most of them have seldom been disclosed to the public. Recently, commercial FEM softwares, such as SAMCEF, ANSYS and NASTRAN, started supporting some rotordynamics analysis modules based on 3-D finite elements. In this paper, the dynamic analysis method using commercial S/W, especially ANSYS, is attempted for the small-size gas turbine engine rotor, and the analysis capability and limitations of its rotordyamics module are evaluated for further improvement of the module. As the preliminary procedure, the rotordyamic analysis capability of ANSYS was tested and evaluated with the reference models of the well-known dynamics. The limitations in application of the rotordynamics module were then identified. Under the current capability and limitations of ANSYS, it is shown that Lee diagram, a new frequency-speed diagram enhanced with the concept of
in rotating machinery, can be indirectly obtained from FRFs computed from harmonic response analysis of ANSYS. Finally, it is demonstrated based on the modeling and analysis method developed in the process of the S/W verification that the conventional Campbell diagram, Lee diagram, mode shapes and critical speeds of the small-size gas turbine engine rotor can be computed using the ANSYS rotordynamics module.
Analysis of the Vibration Transmitting Characteristics of the Insulation-foam for Reducing Refrigerant-induced Noise of a Refrigerator
Han, Hyung-Suk ; Kim, Min-Sung ; Jeong, Weui-Bong ; Seo, Min-Young ; Lee, Soo-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 45~50
DOI : 10.5050/KSNVE.2010.20.1.045
In the refrigerator, the two-phase refrigerant-induced noise of the capillary tube in an evaporator-inlet pipe has been a great concern. The capillary tube is usually covered with insulation-foam packed in the space between inner and outer cabinets without any vibration isolation. Therefore, the refrigerant-induced vibration of the capillary tube can be easily transferred to the outer cabinet, which may increase the radiated noise. In this paper, the characteristics of transferred vibration through the insulation-foam are investigated experimentally by using the refrigerantsupplying equipment. The frequency characteristics, such as dynamic Young's modulus and loss factor, of the insulation-foam are also discussed.
Control Performance Evaluation of MR Fan Clutch for Automotive : Experimental Investigation
Kim, Eun-Seok ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 51~57
DOI : 10.5050/KSNVE.2010.20.1.051
This paper presents temperature control of engine cooling system using a controllable magnetorheological(MR) fan clutch. An appropriate size of MR fan clutch is devised and modeled on the basis of Bingham model. Subsequently, an optimization to determine design parameters such as width of housing is undertaken by choosing the reciprocal of the controllable torque as an objective function. Under consideration of spatial limitation, design parameters are optimally determined using finite element analysis. A sliding mode controller is then designed to control the angular velocity of the MR fan clutch using experimentally determined parameters. The designed controller is experimentally implemented and control performances of the MR fan clutch system are evaluated.
Design and Control of MR Military Suspension System Considering Friction Force
Ha, Sung-Hoon ; Choi, Seung-Bok ; Rhee, Eun-Jun ; Kang, Pil-Soon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 58~65
DOI : 10.5050/KSNVE.2010.20.1.058
This paper presents dynamic modeling and control analysis of a military vehicle suspension featuring MR valve structure. Firstly, the dynamic model of the suspension system which is included gas spring, MR valve and gas chamber is established with respect to the disturbance. Secondly, the friction model of the suspension system is derived by considering experiment result of the MR suspension system. And then, response characteristics of the damping force with respect to the magnetic field and friction force with the proposed friction model are provided to show the feasibility of practical application. In addition, control performance of the proposed MR suspension system is evaluated with quarter vehicle.
Sound Metric for the Impact Sound of a Car
Park, Sang-Won ; Kim, Ho-Wuk ; Na, Eun-Woo ; Lee, Sang-Kwon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 66~73
DOI : 10.5050/KSNVE.2010.20.1.066
Vehicles experience the impact due to harsh road conditions. Contact with a barrier on a road induces vehicles to vibrate, which brings about an impact sound. The attenuation of the impact sound is an important issue since passengers may complain about the impact noise. However, the perfect removal of impact noise is not possible as most of impact noise is caused by external conditions. It is thus necessary to make vehicles to possess more desirable sound quality characteristic of impact sound. More research is needed on objective attributes of impact sound; it is not a simple matter since impact noise is transient in nature and has a high level of sound at an instantaneous moment. A new objective attribute of impact noise is designed by using wavelet transform. Wavelet transform is appropriate for the analysis of transient signals such as impact noise. The usefulness of new objective attribute, which is a sound metric, is examined by comparison with the mean subjective rating for real impact noise of passenger cars. The new sound metric has better correlation with the mean subjective rating than already existing sound metrics
Vibro-acoustic Analysis of Adjoined Two Rooms Using 3-D Power Flow Finite Element Method
Kim, Sung-Hee ; Hong, Suk-Yoon ; Kil, Hyun-Gwon ; Song, Jee-Hun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 74~82
DOI : 10.5050/KSNVE.2010.20.1.074
Power flow analysis(PFA) methods have shown many advantages in noise predictions and vibration analysis in medium-to-high frequency ranges. Applying the finite element technique to PFA has produced power flow finite element method(PFFEM) that can be effectively used for analysis of vibration of complicated structures. PFADS(power flow analysis design system) based on PFFEM as the vibration analysis program has been developed for vibration predictions and analysis of coupled structural systems. In this paper, to improve the function of vibro-acoustic coupled analysis in PFADS, the PFFEM has been extended for analysis of the interior noise problems in the vibro-acoustic fully coupled systems. The vibro-acoustic fully coupled PFFEM formulation based on energy coupled relations is extended to structural system model by using appropriate modifications to structural-structural, structural-acoustic and acoustic-acoustic joint matrices. It has been applied to prediction of the interior noise in two room model coupled with panels, and the PFFEM results are compared to those of statistical energy analysis(SEA).
Analyses of the Cost function for the Reductions of the Dynamic Response and the Vibrational Intensity of a Discrete System and Its Elastic Supporting Beam
Kim, Gi-Man ; Choi, Seong-Dae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 83~91
DOI : 10.5050/KSNVE.2010.20.1.083
In this paper, the feasibility of the cost function having two control factors were discussed in compared to two others which has one different control factor respectively. As of the control factors, the dynamic response of a discrete system and the vibrational intensity at the reference point which is the connecting point of a discrete system to a flexible beam were controlled actively by the control force obtained from the minimization of the cost function. The method of feedforward control was employed for the control strategy. The reduction levels of the dynamic response of a discrete system and the vibrational intensity at a reference point, and also the input power induced by the control force were evaluated numerically in cases of the three different cost functions. In comparison with the results obtained from the cost functions of one control factor, which is the dynamic response or the vibrational intensity, in most cases of the cost function of two control factors the better or similar results were obtained. As a conclusion, it is surely noted that both the dynamic response and the vibrational intensity of the vibrating system be controlled up to the expected level by using the single cost function having two control factors.
Design Parameter Study on the Isolation Performance of the HSLDS Magnetic Vibration Isolator
Shin, Ki-Hong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 92~97
DOI : 10.5050/KSNVE.2010.20.1.092
In general, the softer the stiffness of a linear vibration isolator the better the performance of isolation can be achieved. However, the stiffness of the isolator cannot be made too soft because it needs a sufficient stiffness to hold the load. This is the most critical limitation of a linear vibration isolator. Recently, a HSLDS(high-static-low-dynamic-stiffness) magnetic vibration isolator was proposed to overcome this fundamental limitation. The suggested isolator utilizes two pairs of attracting magnets that introduces negative stiffness. Previously, this new type of vibration isolator was merely introduced and showed a possibility of practical use. In this paper, detailed dynamics of the HSLDS magnetic isolator are studied using computer simulations. Then, the isolation performance is examined for various design parameters to aid the practical use.
Analysis on the Squeal Noise of Wheel Brake System for Tilting Train
Cha, Jung-Kwon ; Park, Yeong-Il ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 20, issue 1, 2010, Pages 98~105
DOI : 10.5050/KSNVE.2010.20.1.098
Squeal, a kind of self-excited vibration, is generated by the friction between the disc and the friction materials. It occurs at the ending stage of the braking process, and radiates and audible frequency range of 1 kHz to 10 kHz. Squeal is generated from unstability because of the coupling between the translation and rotation of the system. This instability is caused by the follower force and follower force is normal component of the friction force. In this paper modal analysis of wheel brake system was performed in order to predict the squeal phenomenon. It was shown that the prediction of system instability is possible by FEM. A finite element model of that brake system was made. Some parts of a real brake was selected and modeled. Modal analysis method performs analyses of each brake system component. Experimental modal analysis was performed for each brake components and experimental results were compared with analytical results from FEM. To predict the dynamic unstability of a whole system, the complex eigenvalue analysis for assembly modeling of components confirmed by modal analysis is performed. The finite element models of the disk brake assembly have been constructed, and the squeal noise problems have been solved by complex eigenvalue analysis. The complex eigenvalue analysis results compared with real train test.