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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 19, Issue 12 - Dec 2009
Volume 19, Issue 11 - Nov 2009
Volume 19, Issue 10 - Oct 2009
Volume 19, Issue 9 - Sep 2009
Volume 19, Issue 8 - Aug 2009
Volume 19, Issue 7 - Jul 2009
Volume 19, Issue 6 - Jun 2009
Volume 19, Issue 5 - May 2009
Volume 19, Issue 4 - Apr 2009
Volume 19, Issue 3 - Mar 2009
Volume 19, Issue 2 - Feb 2009
Volume 19, Issue 1 - Jan 2009
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Modeling of Military Vehicle Suspension System Featuring Disc Spring and MR Valve
Ha, Sung-Hoon ; Choi, Seung-Bok ; Rhee, Eun-Jun ; Kang, Pil-Soon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 979~986
DOI : 10.5050/KSNVN.2009.19.10.979
This paper presents a dynamic modeling of a military vehicle suspension featuring disc spring and MR valve. Firstly, the dynamic model of the disc spring is established with respect to the load and pressure. The nonlinear behavior of the spring is incorporated with the model. Secondly, the dynamic model of the MR valve is derived by considering the pressure drop due to the viscosity and yield stress of MR fluid. The governing characteristics of the proposed suspension system are then investigated by presenting the field-dependent pressure drop of the MR valve and spring force of the gas spring.
Beam Analysis of Underwater Conformal Array by Using Cylindrical Acoustic Holography
Kwon, Hyu-Sang ; Park, Seong-Chol ; Seo, Hee-Seon ; Shin, Gu-Kyun ; Joh, Ghee-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 987~995
DOI : 10.5050/KSNVN.2009.19.10.987
As an experimental technique to analyze the far-field characteristics of underwater cylindrical array sensors, cylindrical acoustic holography is studied. Inside an laboratory water tank, far-field directivity patterns as well as near-field source images are reconstructed from the measured hologram by hydrophone array. Approximate equation for far-field directivity estimation is derived based on stationary phase method. The simulation and experiment show well usefulness of the proposed method in application of underwater array sensors.
Experimental Study of Wet-Brake Squeal Noise in a Forklift
Kim, Tae-Jong ; Jeong, Weui-Bong ; Kim, Moon-Saeng ; Kim, Young-Hyun ; Joo, Won-Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 996~1002
DOI : 10.5050/KSNVN.2009.19.10.996
Elimination of squeal noise occurred during brake application is an important task for the improvement of comforts in an industrial forklift. In this paper, a test rig was developed which was possible for testing of brake noise and an experimental measurement on squeal noise was performed. The causes of the brake noise are identified by experimenting how the factors such as automatic transmission fluid and rpm of drive axle affect the squeal. In order to identify the squeal characteristics, the signal analyses for noise are performed by using frequency spectrums. Also, brake test using a forklift was carried out to confirm the reliability of test results by using a test rig comparing with the occurrence of squeal noise. Experimental results showed that the tendencies of occurrence of squeal noise are well agreed at two test methods by using the test rig and forklift.
Improvement of Torque Characteristics of a Rotatory Two-phase Transverse Flux Machine Optimizing the Shape of Rotor Pole
Ahn, Hee-Tae ; Jang, Gun-Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1003~1011
DOI : 10.5050/KSNVN.2009.19.10.1003
Transverse flux machine(TFM) has been developed to drive a machine of large input power at low-speed. However, it has complicated structure and large torque ripple due to its inherent structure. In this paper the characteristics of torque of a rotatory two-phase TFM are analyzed by using the 3-dimensional finite element method and optimal design. This research shows that one of the effective design variables is the skew angle of permanent magnet. The skew angles of permanent magnet are optimized by using a genetic algorithm. It also shows that the proposed optimal skew magnet not only increases average torque but also decreases torque ripple of a rotatory two-phase TFM.
Reduction of Refrigerant-induced Noise of the Refrigerator by Modification of the Evaporator Inlet Pipe
Kim, Min-Seong ; Han, Hyung-Suk ; Kim, Tae-Hun ; Jeong, Wei-Bong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1012~1020
DOI : 10.5050/KSNVN.2009.19.10.1012
This research is focused on the experimental study of the noise induced by two-phase refrigerant flow in the evaporator. The two-phase flow in the evaporator has various flow patterns. The effects of two-phase flow pattern's characteristics on the noise of the evaporator are investigated experimentally. The experimental data shows that the generated noise is mainly related to the layout of the pipe and the certain two-phase flow patterns such as the churn and slug flow. Based on these results, we removed the unnecessary vertical pipe and changed the pipe diameter of the evaporator - inlet into small one in order to avoid the intermittent flow condition. The noise level of newly-designed inlet-pipe of the evaporator was measured experimentally by refrigerant-supplying equipment and compared with that of conventional one.
Estimation of Damping Matrices for Dynamic Systems
Lee, Gun-Myung ; Kim, Kyung-Ju ; Ju, Young-Ho ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1021~1027
DOI : 10.5050/KSNVN.2009.19.10.1021
Finite element models of dynamic systems can be updated in two stages. In the first stage, mass and stiffness matrices are updated neglecting damping. In the second stage, a damping matrix is estimated with the mass and stiffness matrices fixed. Methods to estimate a damping matrix for this purpose are proposed in this paper. For a system with proportional damping, a damping matrix is estimated using the modal parameters extracted from the measured responses and the modal matrix calculated from the mass and stiffness matrices from the first stage. For a system with non-proportional damping, a damping matrix is estimated from the impedance matrix which is the inverse of the FRF matrix. Only one low or one column of the FRF matrix is measured, and the remaining FRFs are synthesized to obtain a full FRF matrix. This procedure to obtain a full FRF matrix saves time and effort to measure FRFs.
Structure Excitation by Using Beating
Choi, Young-Chul ; Park, Jin-Ho ; Yoon, Doo-Byoung ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1028~1033
DOI : 10.5050/KSNVN.2009.19.10.1028
To detect faults and monitor thinning on a pipe, many people use ultra sonic sensors that are operated in high frequency range. Because there are many modes in high frequency range, it is difficult to find faults and monitor pipe thinning on a structure. If we deal with signals in a low frequency range which include only A0 wave and S0 wave, the information of monitoring and diagnosis can be easily obtained. In this paper, the technique for exciting low frequency range using ultra sonic sensors is proposed. The main idea of the proposed method comes from the beat phenomenon. The beat frequency is equal to the absolute value of the difference in frequency of the two waves. If the beat frequency is tuned by two ultra waves, we can excite A0 mode and S0 mode of structures. To verify the proposed method, we have performed a steel plate and pipe experiments. Experimental results show that two ultra sonic sensors can well excite low frequency range.
Dynamic Modeling and Analysis of a Friction Damper in Drum-type Washing Machine with a Magic Formula Model
Park, Jin-Hong ; Lee, Jeong-Han ; Yoo, Wan-Suk ; Nho, Gyung-Hun ; Chung, Bo-Sun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1034~1042
DOI : 10.5050/KSNVN.2009.19.10.1034
In this paper, the magic formula model was applied for a friction damper in a drum-type washing machine. To describe characteristics of the hysteretic damping force, Physical tests were first carried out to get experimental results using an MTS machine. Then, parameters for the magic formula model were determined from the experimental curves. The ADAMS and MATLAB programs were used for the multibody modeling of the damper and process for parameter identification. The model of drum-type washing machine was applied for a dynamic model of friction damper, in which the accuracy of the proposed damper model was verified.
Tendon Design for Master-slave Manipulator in Consideration of Constrained Force Reflection Control Structure
Kang, Min-Sig ; Yoon, Woo-Hyun ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1043~1052
DOI : 10.5050/KSNVN.2009.19.10.1043
In this work, a master-slave manipulator system which will be used for handling objects contaminated by radioactivity has been addressed. The links of manipulators are driven independently by individual motors installed on the base and the driving torque is transmitted through pre-tensioned tendons. Since the measurable variables are the positions and rates of master/slave motors, only a constrained specific bilateral control structure is available. In the consideration of the flexibility of the tendon and constrained control structure, we derived a necessity for tendon design to prevent uncontrollable vibration mode through a modal analysis. Based on a reduced rigid body model, a control design was suggested and tendons were selected. The feasibility of the proposed analysis and tendon design were verified along with some simulation results.
Numerical Study of Sound Generation Mechanism by a Blast Wave
Bin, Jong-Hoon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1053~1061
DOI : 10.5050/KSNVN.2009.19.10.1053
The goal of this paper is to investigate the generation characteristics of the main impulsive noise sources generated by the supersonic flow discharging from a muzzle. For this, this paper investigates two fundamental mechanisms to sound generation in shocked flows: shock motion and shock deformation. Shock motion is modeled numerically by examining the interaction of a sound wave with a shock. The numerical approach is validated by comparison with results obtained by linear theory for a small disturbance case. Shock deformations are modeled numerically by examining the interaction of a vortex ring with a blast wave. A numerical approach of a dispersion-relation-preserving(DRP) scheme is used to investigate the sound generation and propagation by their interactions in near-field.
Analysis and Evaluation of Impact Sound Insulation of Concrete Floor Structures in Response to Characteristics of Heavy-weight Impact Sources
Yoo, Seung-Yup ; Yeon, Jun-Oh ; Jeon, Jin-Yong ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1062~1068
DOI : 10.5050/KSNVN.2009.19.10.1062
In this study, the impact force levels of bang machine and impact ball were measured, then the heavy-weight impact sounds generated by the bang machine and impact ball were investigated. It was found that the heavy-weight impact sources generated through modal excitation, and the impact force of the impact ball was similar to that of real impact source. The heavy-weight impact sounds were also measured in the real apartments with different slab thickness and floor structures. The results showed that the floor impact sound levels in terms of
, generated by impact ball sounds were reduced by using the resilient isolators. The frequency characteristics of heavy-weight impact sounds at 125 and 250 Hz were consistent with the characteristics of impact force spectrum. However, the difference between the impact sounds and the impact forces were found at 63 and 500 Hz due to the resonance of the floor structure and flanking noise, respectively.
Eigenvalue Analysis of Arbitrarily Shaped, Concave Membranes With a Deep Groove Using a Sub-domain Method
Kang, S.W. ; Yoon, J.I. ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1069~1074
DOI : 10.5050/KSNVN.2009.19.10.1069
A sub-domain method for free vibration analysis of arbitrarily shaped, concave membranes with a deep groove is proposed in the paper. The proposed method divides the concave membrane of interest into two convex regions. The vibration displacement(approximate solution) of each convex region is assumed by linearly superposing plane waves generated at edges of the region. A sub-system matrix for each convex region is extracted by applying a provisional boundary condition to the approximate solution. Finally, a system matrix, which of the determinant gives eigenvalues of the concave membrane, is made by considering the fixed boundary condition(displacement zero condition) at edges and the compatibility condition(the condition of continuity in displacement and slope) at the interface between the two regions. Case studies show that the proposed method is valid and accurate when the eigenvalues by the proposed are compared to those by NDIF method, FEM, or the exact method.
Excess Noise Map for Environmental Standard and Assessment of Noise with Using GIS Data
Ko, Joon-Hee ; Lee, Byung-Chan ; Lim, Jae-Serk ; Park, Su-Jin ; Chang, Seo-Il ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1075~1082
DOI : 10.5050/KSNVN.2009.19.10.1075
Using GIS data of C-si as basic data when making noise map of road traffic, we estimated exactly the noise excess areas and consequently suggested the population and the area exposed to road traffic noise accurately. We made 3D noise map to assess regional distribution of noise quantitatively. The noise map consists of noise prediction model based on data base such as traffic volume and speed changes for estimating quantitatively the noise and 3D urban space model which includes locations of noise sources, 3D buildings, topography and roads. We made noise standard map according to land use conditions and compared this map to road traffic noise map, and consequently made excess noise map. Using excess noise map, we assessed areas which exceed environmental noise level standards and noise guidelines quantitatively and effectively through GIS spatial analysis, and consequently more accurate noise exposed area and noise exposed population could be estimated. To show buildings' outer walls noise exposure, we analyzed 3D urban noise distributions using 3D-analysis of GIS.
Analysis of Transportation Vibration for Truck-Mounted Special Equipments via FEM and Experiments
Song, Oh-Seop ; Lee, Hak-Yeol ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1083~1091
DOI : 10.5050/KSNVN.2009.19.10.1083
Modern military equipments are tend to be mounted on a movable truck for their survivability and operation performance. Special units and electronic equipments installed on the truck experience the vibration caused by road roughness during their transport. The level of the transportation vibration is affected by both road conditions and vehicle speeds. In this paper, various experiments on the vibration characteristics of the equipment are carried out via road tests. Transportation vibration is also investigated by numerical analysis using FEM, and natural frequencies and random responses of the launcher are obtained. The PSD and RMS values of acceleration of the equipment are predicted and compared with test results.
Linear Stability Analysis of a Rotating Disc Brake for Squeal Noise
Kang, Jae-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 19, issue 10, 2009, Pages 1092~1098
DOI : 10.5050/KSNVN.2009.19.10.1092
The squeal propensity of an automotive disc brake system is studied in the theoretical and computational manner. The rotating disc is in contact with two stationary pads and the nonlinear friction is engaged on the contact surface. The friction-coupled equations of motion are derived in the finite element(FE) of the actual brake disc and pad. From the general definition of friction force, the rotation and in-plane mode effects can be included properly in the brake squeal model. The eigenvalue sensitivity analysis and the mode shape visualization at squeal frequencies are also conducted for the detailed investigation. It is found that the squeal propensity is strongly influenced by rotation effect and the in-plane mode can be involved in squeal generation.