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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
Journal Basic Information
Journal DOI :
The Korean Society for Noise and Vibration Engineering
Editor in Chief :
Volume & Issues
Volume 18, Issue 12 - Dec 2008
Volume 18, Issue 11 - Nov 2008
Volume 18, Issue 10 - Oct 2008
Volume 18, Issue 9 - Sep 2008
Volume 18, Issue 8 - Aug 2008
Volume 18, Issue 7 - Jul 2008
Volume 18, Issue 6 - Jun 2008
Volume 18, Issue 5 - May 2008
Volume 18, Issue 4 - Apr 2008
Volume 18, Issue 3 - Mar 2008
Volume 18, Issue 2 - Feb 2008
Volume 18, Issue 1 - Jan 2008
Selecting the target year
Identification on Principle of Acoustic Wave Propagation Characteristics in a Gas Pipe
Kim, Min-Soo ; Lee, Sang-Kwon ; Jang, Sang-Yup ; Koh, Jae-Pil ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 797~804
DOI : 10.5050/KSNVN.2008.18.8.797
In the gas supply pipe, the gas leakage caused by the impact of the construct equipment is serious problem. The identification of the impact position is an important issue and an engineering work. For the basic research of this problem, the principle studies for the acoustic wave propagation in a gas pipe are proceeded in this paper. This principal work is based on the identification of the cut-off frequency associated with major modes of the gas pipe theoretically and experimentally The cut-off frequency is confirmed by STFT and cross-correlation function is used to identify the leakage position.
Interior Noise Reduction of Wheel Loader Using Transfer Path Analysis and Panel Contribution Analysis
Kim, Bo-Yong ; Shin, Chang-Woo ; Jeong, Won-Tae ; Park, Sung-Yong ; Jang, Han-Kee ; Kim, Seong-Jae ; Kang, Yeong-June ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 805~815
DOI : 10.5050/KSNVN.2008.18.8.805
Transfer path analysis(TPA) and panel contribution analysis(PCA) have been used widely to reduce interior noise of mechanical systems. TPA enables us to decompose interior noise into air-borne and structure-borne noises and estimate the path contribution of noise sources. PCA is also used to identify the noise contribution of each sub-panel in vibro-acoustic systems. In this paper, TPA and PCA are applied to wheel loader, one of the heavy construction equipments. Firstly, TPA for air-borne noise is conducted to estimate the contribution of air-borne sources using pressure transfer function. Thereafter, TPA for structure -borne noise is employed to verify the results of air-borne source quantification through the synthesis of two results. Secondly, PCA is performed by both TPA using pressure transfer function between panels inside the cabin and boundry element method(BEM) for the cabin of wheel loader with various boundary conditions. As a results, it was found that TPA conducted by experiments and PCA accomplished by both experiments and BEM are very effective methods in analyzing the path and contribution of the noises for reducing an interior noise level in the wheel loader system.
A Study on the Improvement of Radiated Noise in SCR Muffler of Commercial Vehicle
Lee, Dong-Won ; Kim, Wan-Su ; Bae, Chul-Yong ; Kim, Chan-Jung ; Kwon, Sung-Jin ; Lee, Bong-Hyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 816~822
DOI : 10.5050/KSNVN.2008.18.8.816
This study presents the design modification for SCR muffler of a commercial vehicle. Its main objective is the reduction of radiated noise at SCR muffler. For this study, the research of five steps were achieved by experimental and CAE analysis. First step is the measurement of radiated noise using impact-acoustic test. Second step is the source identification using experimental modal analysis. The cause of radiated noise source is confirmed by the resonance of end plates at SCR muffler. Third step confirms the possibility of resonance avoidance using SDM analysis applied the mass control. Fourth step is the suggestion of design modification which is the change of mode shape by CAE analysis. Last step is the verification of design modification using SYSNOISE analysis. Finally, the prototype product applied the countermeasure of resonance evasion was manufactured and the reduction of radiated noise at SCR muffler was confirmed by pass-by noise test.
Factors for Speech Signal Time Delay Estimation
Kwon, Byoung-Ho ; Park, Young-Jin ; Park, Youn-Sik ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 823~831
DOI : 10.5050/KSNVN.2008.18.8.823
Since it needs the light computational load and small database, sound source localization method using time delay of arrival(TDOA method) is applied at many research fields such as a robot auditory system, teleconferencing and so on. Researches for time delay estimation, which is the most important thing of TDOA method, had been studied broadly. However studies about factors for time delay estimation are insufficient, especially in case of real environment application. In 1997, Brandstein and Silverman announced that performance of time delay estimation deteriorates as reverberant time of room increases. Even though reverberant time of room is same, performance of estimation is different as the specific part of signals. In order to know that reason, we studied and analyzed the factors for time delay estimation using speech signal and room impulse response. In result, we can know that performance of time delay estimation is changed by different R/D ratio and signal characteristics in spite of same reverberant time. Also, we define the performance index(PI) to show a similar tendency to R/D ratio, and propose the method to improve the performance of time delay estimation with PI.
Modal Analysis and Vibration Control of Smart Hull Structure
Sohn, Jung-Woo ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 832~840
DOI : 10.5050/KSNVN.2008.18.8.832
Dynamic characteristics of smart hull structure are investigated and active vibration control performance is evaluated. Dynamic model of smart hull structure with surface bonded macro-fiber composite(MFC) actuators is established by analytical method. Equations of motion of the host hull structure are derived based on Donnell-Mushtari equilibrium equations for a thin cylindrical shell. A general model for the interaction between hull structure and MFC actuator is included in the dynamic model. Modal analysis is then conducted and mode shapes and corresponding natural frequencies are investigated. After constructing of the optimal control algorithm, active vibration control performance of the proposed system is evaluated. It has been shown that structural vibration can be reduced effectively with proper control input.
Development of Experimental Dummy and Measurements of Head-related Transfer Functions(HRTF) for Averaged Korean Head Shape
Lee, Doo-Ho ; Ahn, Tae-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 841~848
DOI : 10.5050/KSNVN.2008.18.8.841
Based on the averaged Korean head shapes that are the results of digital Korean project by KISTI and Catholic university, experimental apparatus of head dummies of Korean male and female are developed in order to measure head-related transfer functions(HRTF) by using a reverse engineering and rapid prototyping techniques. For the Korean dummies, HRTFs are measured using the substitution method ever 12kHz frequency bands. At every azimuth angle
HRTFs are measured for elevation angles
. The measured HRTFs are compared with those of KEMAR(knowles electronic manikin for acoustic research) dummy head, which shows
kHz frequency band.
Measurement of Shear Contact Characteristics on Mechanical Joints
Lee, Chul-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 849~855
DOI : 10.5050/KSNVN.2008.18.8.849
An experimental method based on contact resonance is developed to extract the contact parameters of mechanical joints under various clamped conditions. Mechanical joint parameters of shear contact stiffness and damping were extracted for different physical joint parameters such as surface finish of the mating surfaces, the presence of lubrication, the effect of the clamping pressure, and shear load. It was found that the shear contact stiffness values decreased with increasing clamping load and increased with increasing shear loading. Contact damping ratio values were almost constant with clamping load, but decreased with increasing shear load. Moreover, rough surfaces exhibited the highest shear stiffness and contact damping compared to smooth surfaces.
Control Performance of Friction Dampers Using Flexural Behavior of RC Shear Wall System
Chung, Hee-San ; Moon, Byoung-Wook ; Park, Ji-Hun ; Lee, Sung-Kyung ; Min, Kyung-Won ; Byeon, Ji-Seok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 856~863
DOI : 10.5050/KSNVN.2008.18.8.856
High-rise apartments of shear wall system are governed by flexural behavior like a cantilever beam. Installation of the damper-brace system in a structure governed by flexural behavior is not suitable. Because of relatively high lateral stiffness of the shear wall, a load is not concentrate on the brace and the brace cannot perform a role as a damping device. In this paper, a friction damper applying flexibility of shear wall is proposed in order to reduce the deformation of a structure. To evaluate performance of the proposed friction damper, nonlinear time history analysis is executed by SeismoStruct analysis program and MVLEM(multi vertical linear element model) be used for simulating flexural behavior of the shear wall. It is found that control performance of the proposed friction damper is superior to one of a coupled wall with rigid beam. In conclusion, this study verified that the optimal control performance of the proposed friction damper is equal to 45 % of the maximum shear force inducing in middle-floor beam with rigid beam.
The Study on the Vibrational Characteristics of Korean Tilting Train Hanvit200
Kim, Nam-Po ; Kim, Jung-Seok ; Park, Tae-Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 864~871
DOI : 10.5050/KSNVN.2008.18.8.864
The tilting trains can run on curve track about 30% faster than conventional train without affecting passenger comfort. As the tilting trains offer the optimum means of providing faster and more comfortable rail service with minimum of environmental disturbance and capital investment, it is widely adopted for commercial operation all over the world. Over several years, the Korea Railroad Research Institute(KRRI) and Ministry of Construction and Transportation(MOCT) have been developing 200 km/h Korean tilting train, Hanvit200. Hanvit200 adopts the pendulum type tilting mechanism and hybrid car body structure, mainly CFRP combined with steel. In this paper the vibrational characteristics of Hanvit200 was investigated through Eigen vector analysis, modal test and main line running test.
Development of MEMS Accelerometer-based Smart Sensor for Machine Condition Monitoring
Son, Jong-Duk ; Shim, Min-Chan ; Yang, Bo-Suk ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 872~878
DOI : 10.5050/KSNVN.2008.18.8.872
Many industrial operations require continuous or nearly-continuous operation of machines, interruption of which can result in significant cost loss. The condition monitoring of these machines has received considerable attentions in recent years. Rapid developments in semiconductor, computing, and communication with a remote site have led to a new generation of sensor called "smart" sensors which are capable of wireless communication with a remote site. The purpose of this research is to develop a new type of smart sensor for on-line condition monitoring. This system is addressed to detect conditions that may lead to equipment failure when it is running. Moreover it will reduce condition monitoring expense using low cost MEMS accelerometer. This system is capable for signal preprocessing task and analog to digital converter which is controlled by CPU. This sensor communicates with a remote site PC using TCP/IP protocols. The developed sensor executes performance tests for data acquisition accuracy estimations.
A Rotordynamic Analysis of a Industrial Centrifuge for Vibration Reduction
Kim, Byung-Ok ; Lee, An-Sung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 879~885
DOI : 10.5050/KSNVN.2008.18.8.879
A rotordynamic analysis was performed with a decant-type centrifuge, which is a kind of industrial centrifuge. The system is composed of screw rotor, bowl rotor, driving motors, gear box, and support rolling element bearings. These rotors have a rated speed of 4300 rpm, and were modeled utilizing a rotordynamic FE method for analysis, which was verified through 3-D FE analysis. Design goals are to achieve wide separation margins of lateral critical speeds, and favorable unbalance responses of the rotor in the operating range. Then, a complex analysis rotordynamic analysis of the system was carried out to evaluate its forward synchronous critical speeds and mode shapes, whirl natural frequencies, and unbalance responses under various balance grade. As a result of analysis, the rotordynamic analysis performed by separating a screw rotor and bowl rotor may cause an error in predicting critical speed of entire system. Therefore, the rotordynamic analysis of a coupled rotor combining a screw and bowl rotor must be performed in order to more accurately estimate dynamic characteristics of the decanter-type centrifuge as presented in this paper. Also, rolling element bearings with suitable stiffness should be selected to keep enough separation margin. In addition, in establishing balance grade of a screw and bowl rotor, ISO G2.5 balance grade is more recommended than ISO G6.3, in particular balancing correction of a screw rotor based on ISO G2.5 grade is strongly recommended.
Correlation Between Dynamic Stiffness of Resilient Materials and Lightweight Floor Impact Sound Reduction Level
Kim, Kyoung-Woo ; Jeong, Gab-Cheol ; Sohn, Jang-Yeul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 18, issue 8, 2008, Pages 886~895
DOI : 10.5050/KSNVN.2008.18.8.886
Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material have a close relation with the floor impact sound reduction. In this study, to examine the relationship between dynamic stiffness and lightweight impact sound level, the dynamic stiffness and floor impact sound level of 51 resilient materials were measured. The impact sound level of each of these resilient materials, whose dynamic stiffness was measured, was measured before and after installation, and the level difference (
) was analyzed. The result of test showed that the dynamic stiffness of resilient materials decreased, the lightweight impact sound level also decreased, and there was a correlation between the dynamic stiffness and the lightweight impact sound, especially in the low frequency domain.