• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.20 no.10
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• pp.968-975
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• 2010

The high interest for the ground vibrations which is caused by the train service is risen. When the trains are passed, a serious force is applied to ground and the caused vibration is propagated to the area of the building by the ground and rocks. This vibration comes to feel in the residents with the direct vibration, it is radiated in sound. The caused vibration and radiated sound affect the human's life, and this vibration brings about the operation interruption of the equipment which is sensitive to the vibration, or will bring about the structural damage of the building. In this study, the effect of the vibrations caused by the passing trains on the railway station and buildings is investigated by vibration measurement. Indoor and outdoor measurement is carried out by each trains.

• Journal of the Korean Society for Precision Engineering
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• v.21 no.10
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• pp.102-108
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• 2004

In this paper, we studied a vibration problem that is critical and common to most precision measurement systems. For micro mechanical part measurements, results obtained from the vision-based precision measurement system may contain errors due to the vibration. In order to defeat this generic problem, for the current study, a PC based image processing technique was used first, to assess the effect of the vibration to the precision measurement and second, to develop an in-situ calibration algorithm that automatically compensate the measurement results in real time. We used a set of stereoscopic CCD cameras to acquire the images for the dimensional measurement and the reference measurement. The mapping function was obtained through the in-situ calibration to compensate the measurement results and the statistical analysis for the actual results is provided in the paper. Based on the current statistical study, it is expected to obtain high precision results for the micro measurement systems.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.15 no.4 s.97
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• pp.404-411
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• 2005

To increase accurateness and reliability of the evaluation of power tool vibration transmitted to an operator, it is necessary to measure the grip and feed forces during the measurement of hand-transmitted vibration. In the study a system was invented to measure the vibration and the grip and/or feed force, which consists of a measurement handle and a PC with a data acquisition system and the corresponding software. Strain gauges and an accelerometer were mounted on the handle surface for the simultaneous measurement of the forces and the vibration. The program in the system makes it possible to monitor the grip and feed force during the tool operation so that the operator keeps the applying forces within the pre-determined range. Investigating the vibration total values, frequency-weighted root-mean-square accelerations at the handle, obtained in repetition for each power tool with control of the grip and feed force showed more consistency than those measured without force control. By using the system the experimenter can reduce random error of the measured vibration.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.689-694
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• 2004

To increase accurateness and reliability of the evaluation of power tool vibration transmitted to an operator, it is necessary to measure grip and feed forces during the measurement of hand-transmitted vibration. In the study a system was invented to measure the vibration and the grip and/or feed force, which consists of a measurement handle and a PC with data acquisition system and the software. Strain gauges and an accelerometer were mounted on the handle for the simultaneous measurement of the forces and the vibration. The program in the system makes it possible to monitor the grip and feed force during the tool operation so that the operator keeps the applying forces within the pre-determined range. Investigating the vibration total values, frequency-weighted root mean square accelerations at the handle, obtained at various conditions with control of the grip and feed force showed more consistency than those measured without force control. By using the system the experimenter can reduce uncertainty of the measured vibration.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.22 no.4
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• pp.377-382
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• 2012

This paper presents a proof-of-concept study on the evaluation of torsional vibration isolation performance through in-situ output torque measurement by using a non-contacting magneto-elastic torque transducer installed in the vehicle driveline system. The de-trending processing is first conducted to extract the torsional vibration from the measured driveline output torque. In order to estimate the transmissibility, primary performance indicator of a vibration isolator, the magnitude of transmitted torsional vibration with different frequencies is compared. From the conservative estimation results, the torsional damper built in a lock-up clutch of a torque converter is identified to be a vibration isolator. The evaluation results show that the fluid damping by torque converter outperforms the vibration isolation function of a torsional damper, and the isolation performance needs to be enhanced.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2012.04a
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• pp.382-387
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• 2012

This paper presents a proof-of-concept study on the evaluation of torsional vibration isolation performance through in-situ output torque measurement by using a non-contacting magneto-elastic torque transducer installed in the vehicle driveline system. The de-trending processing is first conducted to extract the torsional vibration from the measured driveline output torque. In order to estimate the transmissibility, primary performance indicator of a vibration isolator, the magnitude of transmitted torsional vibration with different frequencies is compared. From the conservative estimation results, the torsional damper built in a lock-up clutch of a torque converter is identified to be a vibration isolator. The evaluation results show that the fluid damping by torque converter outperforms the vibration isolation function of a torsional damper, and the isolation performance needs to be enhanced.

• Journal of the Ergonomics Society of Korea
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• v.18 no.3
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• pp.179-186
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• 1999

This article aims to provide information necessary for the measurement and analysis of human vibration, especially hand-arm vibration. The major health problems associated with the use of powered hand tools are the signs and symptoms of peripheral vascular and peripheral neural disorders of the fingers and hands. To prevent these problems, it is the first and the most important to measure the amount of the vibration transmitted to the upper extremities, and analyze its characteristics against the exposure limits such as ISO standards. In our country, however, very few studies have been done on the hand-arm vibration. One of the possible reasons might be lack of knowledge for the measurement and analysis schemes. The information introduced in this article would hopefully be of help for the upcoming studies.

• Nuclear Engineering and Technology
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• v.45 no.2
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• pp.249-256
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• 2013

In accordance with the US Nuclear Regulatory Commission (US NRC), Regulatory Guide 1.20, the reactor vessel internals comprehensive vibration assessment program (RVI CVAP) has been developed for an Advanced Power Reactor 1400 (APR1400). The purpose of the RVI CVAP is to verify the structural integrity of the reactor internals to flow-induced loads prior to commercial operation. The APR1400 RVI CVAP consists of four programs (analysis, measurement, inspection, and assessment). Thoughtful preparation is essential to the measurement program, because data acquisition must be performed only once. The optimized design of a vibration and stress measurement system for the RVI CVAP is essential to verify the integrity of the APR1400 RVI. We successfully designed a vibration and stress measurement system for the APR1400 RVI CVAP based on the design materials, the hydraulic and structural analysis results, and performance tests of transducers in an extreme environment. The measurement system designed in this paper will be utilized for the APR1400 RVI CVAP as part of the first construction project in Korea.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.05a
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• pp.466-469
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• 2002

The vibration measurement of the AC motor, the most typically used vibration source, is essential to evaluate the causes of unexpected excessive vibration in many mechanical systems. The motor contributes to excite the resonance of the mechanical systems, and in turn tilt amplified vibration of the mechanical parts cause the motor to vibrate severely. Without the vibration evaluation on the motor itself, it is time consuming to solve the vibration problems. This paper deals the vibration measurement method for the AC motor itself.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2013.04a
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• pp.589-595
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• 2013

A reactor vessel internals comprehensive vibration assessment program(RVI CVAP) of an advanced power reactor 1400(APR1400) is being verified on the integrity of RVI for the design life of the plant by performing the non-prototype category-2 type on the US Nuclear Regulatory Commission Guide(NRC RG) 1.20, for which consists of a vibration and stress analysis program, a limited vibration measurement program, an inspection program, and the correlation of these programs. The aim of this paper is to describe the plan for the vibration measurement, test and acceptance criteria portion, and documentation and results of the APR1400 RVI CVAP. We will conduct the limited vibration measurement program of the APR1400 RVI CVAP according to the measurement plan and the vibration measurement testing in this paper.