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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 23, Issue 12 - Dec 2013
Volume 23, Issue 11 - Nov 2013
Volume 23, Issue 10 - Oct 2013
Volume 23, Issue 9 - Sep 2013
Volume 23, Issue 8 - Aug 2013
Volume 23, Issue 7 - Jul 2013
Volume 23, Issue 6 - Jun 2013
Volume 23, Issue 5 - May 2013
Volume 23, Issue 4 - Apr 2013
Volume 23, Issue 3 - Mar 2013
Volume 23, Issue 2 - Feb 2013
Volume 23, Issue 1 - Jan 2013
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Rear Drum Brake Grunt(stick-slip) Noise Improvement on Braking During Nose-dive & Return Condition
Hong, Ilmin ; Jang, Myunghoon ; Kim, Sunho ; Choi, Hongseok ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 781~788
DOI : 10.5050/KSNVE.2013.23.9.781
Grunt(stick-slip) noise happens between rear lining and drum on braking condition while vehicle is returning to steady position after nose-dive. The study presents a new testing and analysis methods for improving brake grunt noise on vehicle. Grunt noise is called a kind of stick slip noise with below 1 kHz frequency that is caused by the surfaces alternating between sticking to each other and sliding over each other with a corresponding change in friction force. This noise is typically come from that the static friction coefficient of surfaces is much higher than the kinetic friction coefficient. For the identification of the excitation mechanism and improvement of grunt noise, it is necessary to study variable parameters of rear drum brake systems on vehicle and to implement CAE analysis with stick slip model of drum brake. The aim of this study has been to find solution parameters throughout test result on vehicle and dynamo test. As a result of this study, it is generated from stick slip between rear lining and rear drum and it can be solved to reduce contact angle of lining with asymmetric and is effected not only brake drum strength but also rear brake size and brake factor.
A Technique for Measuring Vibration Displacement Using Camera Image
Son, Ki-Sung ; Jeon, Hyeong-Seop ; Park, Jin-Ho ; Park, Jong Won ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 789~796
DOI : 10.5050/KSNVE.2013.23.9.789
Vibration measurements using image processing have been studied by many researchers as it can remotely measure vibration displacements at multiple points simultaneously. It is difficult, however, to obtain accurate displacement from the measured image signals because the resolution of image data is dependent on camera performance and normally lower than that of vibration transducer directly measured. This paper suggests the enhanced technique for vibration displacement measurement by applying the expected value of edge probability distribution to the varying pixel points in the image. The method can both increase the resolution limit of camera image and decrease the measurement errors. The working performance of the proposed technique is verified applying to the vibration measurement of a rotating machine.
Vibration and Stability of Composite Cylindrical Shells Subjected to Electromagnetic and Thermal Fields
Park, Sang-Yun ; Kang, Sunghwan ; Seo, Jung Seok ; Song, Ohseop ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 797~805
DOI : 10.5050/KSNVE.2013.23.9.797
In this paper vibration and stability analysis of laminated composite shells based on the first order shear deformation theory(FSDT) for two different boundary conditions(clamped-clamped, simply supported) are performed. Structural model of cross-ply symmetric laminated composite cylindrical shells subjected to a combination of magnetic and thermal fields is developed via Hamilton's variational principle. These coupled equations of motion are based on the electromagnetic equations(Faraday, Ampere, Ohm, and Lorenz equations)and thermal equations which are involved in constitutive equations. Extended Galerkin method is adopted to obtain the discretized equations of motion. Variations of dynamic characteristics of composite shells with applied magnetic field, temperature gradient, laminate thickness-ratio and radius ratio for two boundary conditions are investigated and pertinent conclusions are derived.
A Study on Main Engine X-mode Vibration Phenomenon due to 2nd Node Torsional Vibration of the Marine Propulsion System
Lee, Donchool ; Kim, Junseong ; Kim, Jinhee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 806~813
DOI : 10.5050/KSNVE.2013.23.9.806
For the past years, higher power rating 2 stroke super long stroke diesel engines having more than 8 cylinders and larger cylinder bore are installed mainly on very large containerships to save on fuel consumption. However, these engines are prone to X-mode vibration due to 2nd node torsional vibration or the X-type moment, particularly because of the increase in total length and height. Recently, cases of excessive X-mode vibration often occurred on engine's major components. This vibration is manifested also as secondary vibration causing failure in engine-mount large structures. This study investigated the excitations caused by the 2nd node propulsion shafting torsional vibration that influence X-mode vibration of the main engine and practical countermeasures are proposed. An 8RT-flex82T 8 cylinder engine and 11S90ME-C 11 cylinder engine for a container ship was used as research model.
Fault Diagnosis of a Rotating Blade using HMM/ANN Hybrid Model
Kim, Jong Su ; Yoo, Hong Hee ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 814~822
DOI : 10.5050/KSNVE.2013.23.9.814
For the fault diagnosis of a mechanical system, pattern recognition methods have being used frequently in recent research. Hidden Markov model(HMM) and artificial neural network(ANN) are typical examples of pattern recognition methods employed for the fault diagnosis of a mechanical system. In this paper, a hybrid method that combines HMM and ANN for the fault diagnosis of a mechanical system is introduced. A rotating blade which is used for a wind turbine is employed for the fault diagnosis. Using the HMM/ANN hybrid model along with the numerical model of the rotating blade, the location and depth of a crack as well as its presence are identified. Also the effect of signal to noise ratio, crack location and crack size on the success rate of the identification is investigated.
A Study on the Development of a Noise Reduction Device Installed at the Top of Noise Barrier for the 400 km/h Class High-speed Railroad
Yoon, Je-Won ; Kim, Young-Chan ; Jang, Kang-Seok ; Hong, Byung-Kook ; Eum, Ki-Young ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 823~830
DOI : 10.5050/KSNVE.2013.23.9.823
The purpose of this study is to develop a noise reduction device installed at the top of noise barrier for further decreasing of noise level of 400 km/h class high-speed railroad. For this, the frequency spectrum of 400 km/h class high-speed railroad was analyzed through the field noise test, and the tuning frequency was determined to design a noise reduction device. The noise reduction device was designed to have noise reduction performance of at least 3 dB(A) using the prediction method(2D BEM) and through the laboratory test with the prototype. Finally, the outdoor test showed that this device could decrease noise level of 400 km/h class high-speed railroad even more than 3 dB(A).
Exposure Characteristics to Noise Among Tunnel Construction Workers
Kim, Kab Bae ; Jang, Jae-Kil ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 831~840
DOI : 10.5050/KSNVE.2013.23.9.831
The noise levels of workers in tunnel sites are likely to be high because tunneling work places are confined space. However, research on the noise exposure levels of tunneling workers have not been performed intensively due to restricted accessibility to tunnel construction sites. The aim of this study is to evaluate the noise exposure levels for workers engaged in tunneling work sites. Noise dosimeters were used for monitoring workers' noise exposure level in 5 tunneling work sites in accordance with the Notification of the Ministry of Labor. Among 5 tunneling work sites, 4 of them used NATM tunneling method and 1 work site used shield TBM tunneling method. The average noise exposure levels of NATM tunneling workers was 81.1 dB(A) and 15.4 % of the workers' noise level were exposed more than 90 dB(A) which is the exposure limit value. In Shield TBM tunneling method, 4.3 % of the workers were exposed more than 90 dB(A) of noise level, the average noise exposure levels of TBM tunneling workers was 84.1 dB(A).
Noise Generation Characteristic for Tunnel Construction Equipments
Jang, Jae-Kil ; Kim, Kab Bae ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 841~849
DOI : 10.5050/KSNVE.2013.23.9.841
Workers engaged in construction works have been exposed to high levels of noise during their work in tunnels. Noise is one of the major health hazards for employees working in construction sites. The aim of this study is to evaluate the noise levels generating from tunneling equipments such as jumbo drills, backhoes, payloaders, shotcrete machines and service cars. Explosion and turbo fan noises were also monitored. A high precision sound level meter was introduced for measuring LAeq, LAFmax, LAFmin and LCpeak noises in 5 tunneling work sites that were located in Seoul, Kyunggi-do and Kangwon-do areas with NATM and shield methods. The highest noise was recorded by explosion(151.9 dB LCpeak) followed by jumbo drills of higher than 110 dB(A) LAeq. Backhoe normally generated 90~110 dB(A) LAeq while breaking work of rock showed additional around 5~15 dB(A). Noise exposure levels for payloader and shotcrete machine scored more than 90 dB(A) which might be a source of noise-induced hearing loss. Additional research in revealing noise levels from construction equipments operating in tunneling works may enhance the protection of workers who exposed to noise primarily at the sites.
Torsional Stress Prediction of Turbine Rotor Train Using Stress Model
Lee, Hyuk-Soon ; Yoo, Seong-Yeon ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 850~856
DOI : 10.5050/KSNVE.2013.23.9.850
Torsional interaction between electrical network phenomena and turbine-generator shaft cause torsional stress on turbine-generator shaft and torsional fatigue fracture on vulnerable component, but the prediction of the torsional stress is difficult because the torsional stress is occurred instantly and randomly. Therefore continuous monitoring of the torsional stress on turbine-generator shaft is necessary to predict the torsional fatigue, but installing the sensors on the surface of the shaft directly to monitor the stress is impossible practically. In this study torsional vibration was measured using magnetic sensor at a point of turbine-generator rotor kit, the torsional stress of whole train of rotor kit was calculated using rotor kit's stress model and the calculated results were verified in comparison with the measured results using strain gauge at several point of turbine-generator rotor kit. It is expected that these experiment results will be used effectively to calculate the torsional stress of whole train of turbine-generator rotor in power plants.
Development of High Temperature Resistant Sound Absorbing Materials Using Meta-aramid Fiber
Kim, Keun-Young ; Seo, Won-Jin ; Jung, Ki-Youn ; Seo, Jong-Beom ; Cho, In-Goo ;
Transactions of the Korean Society for Noise and Vibration Engineering, volume 23, issue 9, 2013, Pages 857~862
DOI : 10.5050/KSNVE.2013.23.9.857
Recently, the importance of GDI and diesel engine noise reduction is required, so newly designed components very close to noise sources are added in order to maximize the sound absorbing performances. In this study, the high temperature resistant part made with meta-Aramid nonwoven, which was applicable for high temperature applications of about
or more, such as engines and exhaust systems, was developed. And three-dimensional shaped component was successfully fabricated, and it was observed high temperature resistance of
, lightweight properties and the noise was decreased by 1.0 dB with 70 g of product.