• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.05a
• /
• pp.766-771
• /
• 2005

To compare blasting vibration at blasting construction field in urban area, the vibration level (dB(V)) and vibration velocity (cm/sec) on the ground and the structure of buildings due to the differences of the measuring sites from the blasting source is investigated and the difference between the measured vertical vibration level and the calculated vibration level by using vibration velocity PVS and the correlation between vibration velocity and vibration level and is studied in the thesis.

• Journal of The Korean Digital Architecture Interior Association
• /
• v.4 no.2
• /
• pp.52-59
• /
• 2004

The interest about noise and vibration which occurs in buildings is increasing by a living level elevation recently. Particularly, the vibration which occurs from the elevator cage of the building is possibility of damage to the users of the building continuously. So, the purpose of this study is to suggest of measuring results to the vibration that occurs from the elevator cage and propose the countermeasure of it.

• Journal of the Korean Society of Safety
• /
• v.16 no.4
• /
• pp.200-207
• /
• 2001

The transmission of harmonic vibratory power form a vibrating rigid body into a supporting plate through passive and active isolators is investigated theoretically and experimentally. The theoretical model allows for the transmission of vertical and horizontal harmonic forces and moments about all three coordinate sun. The experiment is to use vibration actuators attached to the intermediate mass of the two-stage mount to minimize the rotational and translational vibration of the intermediate mass. The performance is done by measuring the vibration at the error sensors due to the primary vibration source and measuring the transfer functions from the control sources to the error sensors. Results show that over a frequence range from 1 to 100Hz, transmission into the supporting plate can be reduced substantially by employing in parallel with existing passive isolators, active isolators adjusted to provide appropriate control force amplitudes.

• Journal of Power System Engineering
• /
• v.13 no.1
• /
• pp.33-38
• /
• 2009

In this study, the nose of cam in the automobile engine was modelled into circular disk to analyze the torsional vibration of the cam shaft. The distance between disks was fixed, but the diameter of disks was changed. The torsional vibration of the cam shaft was studied experimentally by the motion of the modelled disk with changing the disk diameter. And the sizes of the modelled disk were selected not to show the natural frequencies over all the experimental ranges. The torsional vibration meter used in this study has a laser system with non-contact measurement method, which can measure both torsional angular vibration velocity and torsional angular vibration displacement simultaneously. The Experimental analysis shows that the characteristics of the torsional vibration in the horizontal rotating shaft can be considerably affected by the arrangement of the modelled disks.

• Proceedings of the Computational Structural Engineering Institute Conference
• /
• 2002.10a
• /
• pp.362-369
• /
• 2002

This paper mainly propose the new passive vibration control device, named BRV(the bridge reduced vibration), for reducing excessive traffic-induced vibration of bridges and for measuring performance of BRV numerical example was simulated. The purpose of BRV is mainly on reducing vertical acceleration and displacement of bridge. In BRV we can control the stiffness and damping coefficient to accept the performance we want. The result of simulation showed that the vertical acceleration and displacement was effectively diminished. It would be concluded that BRV can be used to improve the serviceability of bridge and fatigue life etc.

• Journal of the Korea Concrete Institute
• /
• v.12 no.3
• /
• pp.77-85
• /
• 2000

Various concretes are used for construction works depending on the types of structure, building element and method of construction. An internal vibration work is one of the important processes for adequately pouring various concrete into a certain form. This study was undertaken to find out the effects of internal vibration on flowability of fresh concrete by concrete flow test under eight conditions of vibration. Presumable equation models also were created to show all vibration effects without regard to kinds of concrete. As the results of this study, the degree of vibration effects were varied according to the properties of concrete. Acceleration amplitude of vibration that applied to fresh concrete was effective value of the properties of vibration in a viewpoint of flowability. Moreover, This research presents the presumed equation models including variables created by acceleration amplitude and measuring value of vibrated concrete flow test. These models are presumable methods of vibration effects regardless of kinds of concrete.

• The Transactions of The Korean Institute of Electrical Engineers
• /
• v.58 no.2
• /
• pp.270-277
• /
• 2009

This paper deals with a vibration and efficiency characteristics of Permanent Magnet Linear Synchronous Motor according to the PM arrangement. The generated force such as the thrust, detent force, normal force and lateral force are compared with analysis values and experimental ones. Furthermore characteristics of vibration and efficiency are estimated by experiments.

• Transactions of the Korean Society for Noise and Vibration Engineering
• /
• v.16 no.1 s.106
• /
• pp.34-39
• /
• 2006

For the evaluation of the normalized impact sound pressure level, the reverberation time of the receiving room should be measured. This paper deals with the effect of the time constant of FFT analyzer and the measuring points on reverberation time. It is found that the time constant should be in the range between 10 ms and 35 ms. While the effect of measuring points on the reverberation time is significant when the bandwidth is narrow it is negligible in the evaluation of the normalized impact sound pressure level.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2000.11a
• /
• pp.425-430
• /
• 2000

This paper describes the effect of the pad stiffness on the noise reduction of impact noise isolation pads of a floor. And also a new semi-experimental method for measuring the impact noise isolation capability of a pad is introduced. The impact noise isolation pads made of wire-mesh, urethane-chip and foam rubber are used for measuring the stiffness, the vibrational insulation performance and the impact noise isolation capability. The correlation between the stiffness and impact noise isolation capability of pads is theoretically reviewed, and confirmed from the experimental results. For measuring the impact noise isolation capability of only an isolation pad, a semi-experimental method proposed in this study is more effective than the reverberation room method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
• /
• 2005.11a
• /
• pp.844-848
• /
• 2005

A method to predict the strain responses from the measurements of displacement responses is considered. The method uses a transformation matrix which is composed of a displacement modal matrix and a strain modal matrix. The method can predict strains at points where displacements are not measured as well as at displacement measuring points. One of the drawbacks of the strain prediction method is that the displacement responses must be measured at many points on a structure simultaneously. This difficulty can be overcome by measuring the FRFs between displacements at a reference point and other point in sequence with a two channel measuring equipment This procedure is based on the assumption that the characteristics of excitation applied to the structure do not vary with time.