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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 16, Issue 12 - Dec 2006
Volume 16, Issue 11 - Nov 2006
Volume 16, Issue 10 - Oct 2006
Volume 16, Issue 9 - Sep 2006
Volume 16, Issue 8 - Aug 2006
Volume 16, Issue 7 - Jul 2006
Volume 16, Issue 6 - Jun 2006
Volume 16, Issue 5 - May 2006
Volume 16, Issue 4 - Apr 2006
Volume 16, Issue 3 - Mar 2006
Volume 16, Issue 2 - Feb 2006
Volume 16, Issue 1 - Jan 2006
Selecting the target year
Comparison of Standard Floor Impact Sources with a Human Impact Source
Lee, Pyoung-Jik ; Jeong, Jeong-Ho ; Park, Jun-Hong ; Jeon, Jin-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 789~796
DOI : 10.5050/KSNVN.2006.16.8.789
The characteristics of the four standard floor impact sources (impact ball, bang machine, tapping machine, modified tapping machine) and a human impact source (jumping children) were investigated. First, the mechanical impedance of each source were evaluated. Then, the impact force exposure level of each source were measured. The results showed that fundamental frequency and impedance produced by the impact ball are the most similar to those of the human impact source. The frequency characteristics of the impact ball were most similar to those of jumping children. Consequently, the impact ball more accurately reproduces human impact compared to the other standard impact sources. Therefore, the impact ball should be considered as the reliable impactor in evaluating floor impact noise.
Sound Quality Characteristics of Refrigerator Noise in Real Living Environments
You, Jin ; Chang, Ho-Yeon ; Lee, Chung-Hwa ; Jeong, Jeong-Ho ; Jeon, Jin-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 797~805
DOI : 10.5050/KSNVN.2006.16.8.797
The sound quality characteristics of refrigerator noise in an anechoic chamber and in a real living environment for 30 models of refrigerators were investigated. Subjective evaluation experiments were conducted to determine subjective tolerance level for refrigerator noise. Refrigerator noise was played from a loudspeaker at the position normally occupied by a refrigerator in a real living environment. A nine-point scale was used to measure subjective satisfaction of the sound pressure levels for refrigerator noise. Point 3 on the scale corresponded to a sound pressure level of about 30 dB(A). Seventy percent of the participants were satisfied with this level of refrigerator noise. A semantic differential test was also conducted to evaluate the sound quality of refrigerator noise. From the results of correlation and multiple regression analyses on the psychoacoustical parameters and subjective evaluations of 30 refrigerators, sound quality indices which predict the subjective rating score were proposed.
The Study on Interrelationship Analysis of Domestic Road Using PSD
Kim, Chan-Jung ; Kwon, Seong-Jin ; Lee, Bong-Hyun ; Kim, Hyun-Chul ; Bae, Chul-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 806~813
DOI : 10.5050/KSNVN.2006.16.8.806
An important factor of vibration test using MAST(multi axial simulation table) system is the reliance of input excitation source. Generally the generation of input excitation source is obtained by the measured data on special road in proving ground. The measured data on special road have more exciting energy than the data of real fields, therefore the time and expense for test can be reduced. But the magnitude of input excitation source must be defined by comparison with the excited energy on real field. The object of this paper makes the data base of domestic roads for the definition of input excitation source which is obtained by the measured data on special road in proving ground. These real field data on domestic roads are analyzed by the power spectral density and interrelationship index.
Dynamic Model Establishment of a Nonlinear Structure with Sliding Mode Condition Using the Substructure Synthesis Method
Kim, Dae-Kwan ; Lee, Min-Su ; Ko, Tae-Hwan ; Han, Jae-Hung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 814~821
DOI : 10.5050/KSNVN.2006.16.8.814
A structural coupling method is developed for the dynamic analysis of a nonlinear structure with concentrated nonlinear hinge joints or sliding lines. The component mode synthesis method is extended to couple substructures and the nonlinear models. In order to verify the improved coupling method, a numerical plate model consisting of two substructures and torsional springs, is synthesized by using the proposed method and its modal parameters are compare with analysis data. Then the coupling method is applied to a three-substructure-model with the nonlinearity of sliding lines between the substructures. The coupled structural model is verified from its dynamic analysis. The analysis results show that the improved coupling method is adequate for the structural nonlinear analyses with the nonlinear hinge and sliding mode condition.
Vibration Control of Quarter Vehicle ER Suspension System Using Fuzzy Moving Sliding Mode Controller
Sung, Kum-Gil ; Cho, Jae-Wan ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 822~829
DOI : 10.5050/KSNVN.2006.16.8.822
This paper presents a robust and superior control performance of a quarter-vehicle electrorheological (ER) suspension system. In order to achieve this goal, a moving sliding mode control algorithm is adopted, and its moving strategy is tuned by fuzzy logic. As a first step, ER damper is designed and manufactured for a passenger vehicle suspension system, and its field-dependent damping force is experimentally evaluated. After formulating the governing equation of motion for the quarter-vehicle ER suspension system, a stable sliding surface and moving algorithm based on fuzzy logic are formulated. The fuzzy moving sliding mode controller is then constructed and experimentally implemented. Control performances of the ER suspension system are evaluated in both time and frequency domains.
A Study on the Analysis of Squeal Noise for Brake Design
Kim, Chan-Jung ; Lee, Dong-Won ; Lee, Bong-Hyun ; Na, Byung-Chul ; Kim, Hyun-Chul ; Kwon, Seong-Jin ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 830~839
DOI : 10.5050/KSNVN.2006.16.8.830
The phenomenon of squeal noise in the disk brake system has been, and still is, a. problem for the automotive industry. Extensive research has been carried out in an attempt to understand the mechanism that causes squeal noise and In developing design procedures to reduce squeal noise to make vehicles more comfortable. In this paper, the study on the analysis of squeal noise is performed by using computer aided engineering to design the anti-squeal noise disk brake system. The first part describes the chassis dynamometer and the testing procedure, and second part explains the finite element model and the complex eigenvalue analysis. Finally, it is shown that the proposed squeal noise analysis could be useful to investigate the design parameters that affect the squeal noise characteristics.
Dynamic Modeling and Vibration Control of Smart Hull Structure
Sohn, Jung-Woo ; Kim, Heung-Soo ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 840~847
DOI : 10.5050/KSNVN.2006.16.8.840
Dynamic modelingand active vibration control of smart hull structure using Macro Fiber Composite (MFC) actuators are conducted. Finite element modeling is used to obtain equations of motion and boundary effects of smart hull structure. Modal analysis is carried out to investigate the dynamic characteristics of the smart hull structure, and compared to the results of experimental investigation. Negative velocity feedback control algorithm is employed to investigate active damping of hull structure. It is observed that non-resonant vibration of hull structure is suppressed effectively by the MFC actuators.
An Experimental Investigation of the Aeroelastic Stability of Next-generation Blade for Helicopter
Kim, Joune-Ho ; Kim, Seung-Ho ; Lee, Je-Dong ; Rhee, Wook ; Song, Keun-Woong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 848~856
DOI : 10.5050/KSNVN.2006.16.8.848
This paper describes the aeroelastic stability test of the small-scaled `Next-generation Blade(NRSB)` with NRSH (next-generation hub system) and HCTH hingeless hub system in hover and forward flight conditions. Excitation tests of rotor system installed in GSRTS (general small-scale rotor test system) at KARI (Korea Aerospace Research Institute) were carried out to get lead-lag damping ratio of blades with flexures as hub flexure. MBA(moving block analysis) technique was used for the estimation of lead-lag damping ratio. First, NRSB-1F blades with HCTH hub system, then NRSB- 1F with NRSH hub system were tested. Second, NRSB-2F blades with NRSH hub system were tested. Tests were done on the ground and in the wind tunnel according to the test conditions of hover and forward flight, respectively. Non-rotating natural frequencies, non-rotating damping ratios and rotating natural frequencies were showed similar level for each cases. Estimated damping ratios of NRSB-1F, NRSB-2F with HCTH and NRSH were above 0.5%, and damping ratio increased by collective pitch angle increasement. Furthermore damping ratios of NRSB-2F were higher than damping ratios of NRSB-1F in high Pitch angle. It was confirmed that the blade design for noise reduction would give observable improvement in aeroelastic stability compared to paddle blade and NRSB-1F design.
Sound Characteristics and Performance of Even and Uneven Blade Spacing Helicopter Anti-Torque System
Song, Keun-Woong ; Chung, Ki-Hoon ; Kang, Hee-Jung ; Kim, Seung-Bum ; Lee, Je-Dong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 857~863
DOI : 10.5050/KSNVN.2006.16.8.857
This paper described the performance test and sound characteristics of helicopter `Tail-Fan` anti-torque system. In this research, Korea Aerospace Research Institute(KARI) developed `Tail-Fan` anti-torque system for a helicopter and carried out performance and sound capturing tests of even and uneven tail fans. The performance test is carried out and the noise signals which are generated during the test are saved with microphones at the same time. The performance test`s results meet the design requirements. Tone-corrected perceived noise level is reduced by replacing the even product with the uneven one.
Characteristics of Noise Emission from Wind Turbine According to Methods of Power Regulation
Cheong, Cheol-Ung ; Cheung, Wan-Sup ; Shin, Su-Hyun ; Chun, Se-Jong ; Choi, Yong-Moon ; Jung, Sung-Soo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 864~871
DOI : 10.5050/KSNVN.2006.16.8.864
In the development of electricity generating wind turbines for wind farm application, only two types have survived as the methods of power regulation; stall regulation and full span pitch control. The main purpose of this paper is to experimentally identify the characteristics of noise emission of wind turbines according to the power regulation types. The sound measurement procedures of IEC 61400-11 are applied to field test and evaluation of noise emission from each of 1.5 MW and 660 kW wind turbines (WT) utilizing the stall regulation and the pitch control for the power regulation, respectively. Apparent sound power level, wind speed dependence, third-octave band levels and tonality are evaluated for both of WTs. It is observed that equivalent continuous sound pressure levels (ECSPL) of the stall control type of WT continue to increase with increasing wind speed whereas those of the pitch control type of WT show less correlation with wind speed. These observed characteristics are believed to be due to the different airflow patterns around the blade between the stall regulation and the pitch control types of WT; the airflow on the suction side of blade in the stall types of WT are separated at the high wind speed. It is also found that the 1.5 MW WT using the stall control emits lower sound power than 660 kW one using the pitch control at wind speeds below 8m/s, whereas sound power of the former becomes higher than that of the latter in the wind speed over 8m/s. This wind-speed dependence of sound power leads to the very different noise omission characteristics of WTs depending on the seasons because the average wind speed in summer is lower than 8m/s whereas that in summer is higher. Based on these experimental observations, it is proposed that, in view of environmental noise regulation, the developer of wind farm should give enough considerations to the choice of power regulation of their WTG based on the weather conditions of potential wind farm locations.
Loose-part Mass Estimation Using Time-frequency Analysis
Park, Jin-Ho ; Yoon, Doo-Byung ; Park, Keun-Bae ; Choi, Young-Chul ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 872~878
DOI : 10.5050/KSNVN.2006.16.8.872
Mass estimation was derived as functions of acceleration magnitude and primary frequency. The conventional method of mass estimation used frequency data directly in the frequency domain. The signals that can be obtained sensor contained noise as well as impact signal. Therefore, how well we can detect the frequency data in noise directly determines the quality of mass estimation. To find exact frequency data, we used time-frequency analysis. The time-frequency methods are expected to be more useful than the conventional frequency domain analyses for the mass estimation problem on a plate type structure. Also it has been concluded that the smoothed WVD can give more reliable means than the other methodologies for the mass estimation in a noisy environment.
Torsional Modal Testing of a Non-ferromagnetic Shaft by Magnetostrictive Patch Transducers
Cho, Seung-Hyun ; Han, Soon-Woo ; Park, Chan-Il ; Kim, Yoon-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 879~885
DOI : 10.5050/KSNVN.2006.16.8.879
Torsional vibration is an important vibration mode when shafts, cylinders and pipes are considered. However, the modal testing of torsional vibrations is not an easy task to carry out because of the lack of proper transducers. This work presents a new torsional vibration transducer based on the magnetostrictive principle and its application to torsional modal testing. The transducer is so designed as to generate/measure only torsional vibrations excluding other vibration modes such as longitudinal and bending vibrations. The transducer is composed of ferromagnetic patches bonded to a test structure, permanent magnets, and a solenoid. Though patches and magnets are bonded to a structure, torsional vibrations are generated and measured wirelessly by a solenoid encircling a test structure. The proposed transducer works even at considerably high frequencies, say, tens of kilohertz. Furthermore, the transducer can be manufactured at a low price. To check the performance of the proposed method, the torsional modal testing on a hollow aluminum shaft was conducted. The results, such as eigenfrequencies, obtained by the proposed transducer agreed favorably with theoretical results.
The Origin and Effect of Hot Spot Phenomena on Judder Vibration in Automotive Disk Brake
Cho, Chong-Du ; Kim, Myoung-Gu ; Cho, Ho-Joon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 16, issue 8, 2006, Pages 886~892
DOI : 10.5050/KSNVN.2006.16.8.886
Hot spot phenomenon is caused by non-uniform contact area between brake pad and disk frequent braking. Brake disk deformed by locally concentrated heat increases magnitude of frictional vibration. And this deformation can highly influence the judder vibration. In this experimental study, vibration and hot spot was measured in accordance with rotation of disk and pressure of master cylinder for finding the factors that causes hot spot phenomena. For comparing hot spot aspects with mode shapes of disk, mode shapes were measured by conducting modal test, and analyzed by using finite element analysis. Relation between hot spot phenomenon, and mode shape, pressure of master cylinder and rotation speed of disk respectively, was achieved by hot spot measurement and frequency analysis.