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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
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Volume & Issues
Volume 22, Issue 12 - Dec 2012
Volume 22, Issue 11 - Nov 2012
Volume 22, Issue 10 - Oct 2012
Volume 22, Issue 9 - Sep 2012
Volume 22, Issue 8 - Aug 2012
Volume 22, Issue 7 - Jul 2012
Volume 22, Issue 6 - Jun 2012
Volume 22, Issue 5 - May 2012
Volume 22, Issue 4 - Apr 2012
Volume 22, Issue 3 - Mar 2012
Volume 22, Issue 2 - Feb 2012
Volume 22, Issue 1 - Jan 2012
Selecting the target year
Stability Analysis of Axially Moving Simply Supported Pipe Conveying Fluid
Son, In-Soo ; Hur, Kwan-Do ; Lee, Sang-Pill ; Cho, Jeong-Rae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 407~412
DOI : 10.5050/KSNVE.2012.22.5.407
The dynamic instability and natural frequency of an axially moving pipe conveying fluid are investigated. Thus, the effects of fluid velocity and moving speed on the stability of the system are studied. The governing equation of motion of the moving pipe conveying fluid is derived from the extended Hamilton`s principle. The eigenvalues are investigated for the pipe system via the Galerkin method under the simple support boundary. Numerical examples show the effects of the fluid velocity and moving speed on the stability of system. Moreover, the lowest critical moving speeds for the simply supported ends have been presented.
Condition Monitoring of Rotating Machine with a Change in Speed Using Hidden Markov Model
Jang, M. ; Lee, J.M. ; Hwang, Y. ; Cho, Y.J. ; Song, J.B. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 413~421
DOI : 10.5050/KSNVE.2012.22.5.413
In industry, various rotating machinery such as pumps, gas turbines, compressors, electric motors, generators are being used as an important facility. Due to the industrial development, they make high performance(high-speed, high-pressure). As a result, we need more intelligent and reliable machine condition diagnosis techniques. Diagnosis technique using hidden Markov-model is proposed for an accurate and predictable condition diagnosis of various rotating machines and also has overcame the speed limitation of time/frequency method by using compensation of the rotational speed of rotor. In addition, existing artificial intelligence method needs defect state data for fault detection. hidden Markov model can overcome this limitation by using normal state data alone to detect fault of rotational machinery. Vibration analysis of step-up gearbox for wind turbine was applied to the study to ensure the robustness of diagnostic performance about compensation of the rotational speed. To assure the performance of normal state alone method, hidden Markov model was applied to experimental torque measuring gearbox in this study.
The Study of Correlation between Objective Human Response and Subjective Discomfort Evaluation of Idle Vibration on Passenger Vehicle
Lee, Jae-Young ; Jeon, Gyeoung-Jin ; Ahn, Se-Jin ; Jeong, Weui-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 422~428
DOI : 10.5050/KSNVE.2012.22.5.422
Thirteen taxi drivers as the subject in the experiment were exposed to vertical vibration which is controlled on a rigid seat reflecting vibration on passenger vehicle. They were employed not only to get human response of objective measurement but also to make subjective evaluation of the vibration. The subjective evaluation was estimated using the absolute discomfort threshold of the controlled vibration, which was achieved with the three-down one-up method that is widely used in the field of psychophysics. As the result, apparent mass and apparent eccentric mass as objective human response tend to gradually decrease when frequency of the vibration increases. The absolute discomfort threshold was increased in case of increasing the frequency. Concludingly, the subjective discomfort evaluation is highly correlated with the objective human responses at the range of idle vibration on passenger vehicle.
Effect of Acoustic Reflector`s Surface Density on Sound Absorption Characteristics and Stage Acoustics
Kim, Young-Sun ; Jeong, Jeong-Ho ; Jeon, Jin-Yong ; Kim, Myeong-Seok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 429~436
DOI : 10.5050/KSNVE.2012.22.5.429
In concert halls and auditoriums, acoustic reflector and stage enclosure is one of the main factors on the room and stage acoustic characteristics. As a stage enclosure and acoustic reflector honey comb based light-weight reflector is widely used, because it is easy to install. However, there was not enough research on the surface density effect on room and stage acoustics. In this study, sound absorption coefficient tests on three kinds of wooden acoustic reflectors with different surface density were conducted. Surface density of acoustic reflector was changed from 11 kg/
to 41 kg/
. For the low frequency excitation, sub-woofer was used with omnidirectional loud-speaker simultaneously. From the experiments, it was found that sound absorption coefficient below 250 Hz band was decrease by the increment of surface density. In order to check the influence of the surface density on room and stage acoustic parameters, room acoustic simulation was conducted with sound absorption coefficients, which were tested in reverberation chamber. By the increment of surface density of acoustic reflector, RT(reverberation time) and EDT(early decay time) were increased. Also, ST(stage support) was improved in low frequency bands.
Force Identification and Sound Prediction of a Reciprocating Compressor for a Refrigerator
Kim, Sang-Tae ; Jeon, Gyeoung-Jin ; Jeong, Weui-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 437~443
DOI : 10.5050/KSNVE.2012.22.5.437
In this paper, the hybrid method to identify the exciting forces and radiated noise generated from the reciprocating compressor was presented. In order to identify the exciting force, both the acceleration data measured at the compressor shell and numerical finite element model for the full set of compressor were used simultaneously. Applying the identified exciting forces to the numerical model, the velocity responses of all nodes at the shell were predicted. Finally the radiated noises from the vibrating shell were predicted by using the direct boundary element acoustic analysis. For precise numerical modeling, the stiffness of rubber mounts and body springs were identified experimentally from the natural frequencies measured by impact testing. The error of over-all sound pressure level between predicted noise and measured noise was about 2.9 dB.
Computation of Serrated Trailing Edge Flow and Noise Using a Hybrid Zonal RANS-LES
Kim, Tae-Hyung ; Lee, Seung-Hoon ; Lee, Soo-Gab ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 444~450
DOI : 10.5050/KSNVE.2012.22.5.444
The evaluation of a zonal RANS-LES approach is documented for the prediction of broadband noise generated by the flow past unmodified and serrated airfoil trailing edges at a high Reynolds number. A multi-domain decomposition is considered, where the acoustic sources are resolved with a LES sub-domain embedded in the RANS domain. A stochastic vortex method is used to generate synthetic turbulent perturbations at the RANS-LES interface. The simulations are performed with a general-purpose unstructured control-volume code FLUENT. The far-field noise is calculated using the aeroacoustic analogy of Ffowcs Williams-Hawkings. The results of the simulation are validated through the full-scaled wind turbine acoustic measurements. It is found that the present approach is adequate for predicting noise radiation of serrated trailing edge flow for low noise rotor system.
Development of a Solenoid Control Technique for the Suppression of Noise and Vibrations of the Brake System of Elevator Traction Machine
Yang, Dong-Ho ; Kim, Ki-Young ; Heo, Seok ; Kwak, Moon-K. ; Lee, Jae-Ha ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 451~458
DOI : 10.5050/KSNVE.2012.22.5.451
This paper is concerned with the suppression of noise and vibrations of the brake system of elevator traction machine by means of a solenoid control technique. The solenoid is used to hold the brake shoe, which is then released by turning the solenoid off. Since the brake shoe hits the brake disk, vibrations and noise occur. We developed the solenoid control technique based on the dynamic behavior of the solenoid. The theoretical model for the solenoid is modeled by using linear magnetic principles. The solenoid model was then combined with the vibration model to simulate the vibrations of brake system. The simulation results show that the additional pulse input to the solenoid can decrease the vibrations. The timing of the applied pulse is determined by observing the current. The experimental results show that both the vibrations and noise can be substantially decreased, which validates the approach developed in this paper.
Optimal Design of a Magnetorheological Haptic Gripper Reflecting Grasping Force and Rolling Moment from Telemanipulator
Nguyen, Quoc-Hung ; Oh, Jong-Seok ; Choi, Seung-Bok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 459~467
DOI : 10.5050/KSNVE.2012.22.5.459
In this work, the configuration of a haptic gripper featuring magnetorheological(MR) brakes is proposed and an optimal design of the MR brakes for the haptic griper is performed considering the required braking torque, the uncontrollable torque(zero-field friction torque) and mass of the brakes. Several configurations of MR brake is proposed such as disc-type, serpentine-type and hybrid-type. After the configurations of the MR brakes are proposed, braking torque of the brakes is analyzed based on Bingham rheological model of the MR fluid. The zero-field friction torque of the MR brakes is also analyzed. An optimization procedure based on finite element analysis integrated with an optimization toolbox is developed for the MR brakes. The purpose of the optimal design is to find optimal geometric dimensions of the MR brake structure that can produce the required braking torque and minimize the mass of the MR brakes. In addition, the uncontrollable torque of the MR brakes is constrained to be much smaller than the required braking torque. Based on the developed optimization procedure, optimal solution of the proposed MR brakes are achieved and the best MR brake is determined. The working performance of the optimized MR brake is then investigated.
Development of Shipboard Large-sized Low-noise Room Unit with Multiple Outlets
Kim, Sang-Ryul ; Kim, Hyun-Sil ; Lee, Sung-Hyun ; Park, Keun-Hyo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 468~473
DOI : 10.5050/KSNVE.2012.22.5.468
In this paper, the acoustic performance of a shipboard large-sized room unit is studied. The room unit is a kind of rectangular absorptive chamber with a partition whose surface absorptive material with fabric skin is attached to. The room unit has one inlet and three outlets. At the inlet, a plane damper is installed to control the flow rate. The acoustic performance of a prototype room unit is measured using a HVAC mock-up. It is shown that its insertion loss is comparable with that of a commercially-used room unit but the developed room unit generates flow noise higher than the other one. The major source of flow noise is analyzed by NADS-R, the noise analysis program for room unit. Cone-shaped dampers are proposed to be used as the damper of a room unit to reduce flow noise. It is shown that the cone-shaped damper decrease flow noise remarkably.
Structural Analysis and Response Measurement Locations of Inner Barrel Assembly Top Plate in APR1400
Ko, Do-Young ; Kim, Kyu-Hyung ; Kim, Sung-Hwan ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 474~479
DOI : 10.5050/KSNVE.2012.22.5.474
A comprehensive vibration assessment program for the advanced power reactor 1400(APR1400) reactor vessel internals is established in accordance with the united states nuclear regulatory commission regulatory guide 1.20 revision 3. This paper is related to instruments and measurement locations based on the vibration and stress response analysis results of the inner barrel assembly top plate in APR1400. The analysis results of the inner barrel assembly top plate in the reactor show that the deterministic stress and deformation due to the reactor coolant pump induced pressure pulsations are larger than the random stress and deformation induced by the flow turbulence. The selection of the instruments and measurement locations at inner barrel assembly top plate in the reactor is essential requirements and very important study process for the vibration and stress measurement program in comprehensive vibration assessment program for APR1400 reactor vessel internals.
Modal Test and Finite Element Model Update of Aircraft with High Aspect Ratio Wings
Kim, Sang-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 22, issue 5, 2012, Pages 480~488
DOI : 10.5050/KSNVE.2012.22.5.480
The aircrafts with high aspect ratio wings made by a composite material have been developed, which enable high energy efficiency and long-term flight by reducing air resistance and structural weight. However, they have difficulties in securing the aeroelastic stability such as the flutter because of their long and flexible wings. The flutter is unstable self-excited-vibration caused by interaction between the structural dynamics and the aerodynamics. It should be verified analytically prior to first flight test that the flutter does not happen in the range of flight mission. Normally, the finite element model is used for the flutter analysis. So it is important to construct the finite element model representing dynamic characteristics similar to those of a real aircraft. Accordingly, in this research, to acquire dynamic characteristics experimentally the modal test of the aircraft with high aspect ratio composite wings was conducted. And then the modal parameters from the finite element analysis(FEA) were compared with those from the modal test. To make analysis results closer to test results, the finite element model was updated by means of the sensitivity analysis on variables and the optimization. Finally, it was proved that the updated finite element model is reliable as compared with the results of the modal test.