• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.53-58
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• 2001

Floor impact sound has caused many acoustical complaints to the apartment building dwellers. The concrete floating floor construction is one of the most reasonable way to reduce floor impact sound. Recently, many damping materials are used in apartment buildings. In this study, to evaluate floor impact sound insulation performance, field tests were carried at five building floors with damping materials. The test results of impact sound insulation performance for five buildings showed good improvement in light weight impact sound after installation of damping materials, but heavy weight impact sound wasn't improved.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.11a
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• pp.269-274
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• 2004

The aims of this study were to Investigate the floor impact noise isolation performance of floating floor with isolation materials and propose the improvement direction of floor impact noise measurement method and evaluation classes using impact ball. Reduction of light-weight impact sound pressure level can be achieved by the finishing materials, such as vinyl finishing material and wooden flooring with isolation materials. Floor impact noise Isolation material which satisfy the properties of the floor impact noise isolation materials cause resonance in the low frequency band and worsen heavy-weight impact sound pressure level. Heavy-weight impact sound level can be reduced by using noise reduction flooring, ceiling and increase of slab thickness. Strong impact force in low frequency bang below 63Hz of bang machine is not similar to human impact source and causes some problem in evaluating heavy-weight impact noise but heavy-weight impact noise measurement and evolution using impact ball which is very similar to human impact is more reliable than bang machine. Correction value on the background noise and sensitivity of residents should be considered on the floor impact noise evaluation classes.

• Journal of the Society of Naval Architects of Korea
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• v.52 no.1
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• pp.77-87
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• 2015

For a floating offshore plant such as FPSO(Floating, Production, Storage, and Off-loading unit), various equipment should be installed in the restricted space, as compared with an onshore plant. The requirement for an optimal layout method of the plant has been increased in these days. Thus, a layout method of the floating offshore plant was proposed in this study. For this, an optimization problem for layout design was mathematically formulated, and then an optimization algorithm based on the genetic algorithm was implemented with C++ language in order to solve it. Finally, the proposed method was applied to an example of FPSO topsides. As a result, it was shown that the proposed method can be applied to layout design of the floating offshore plant such as FPSO.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.21 no.9
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• pp.805-812
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• 2011

This study investigated the characteristics of heavy-weight floor impact sounds of box-frame type structure using 1:10 scale model. Ten types of floor structures(bare slabs and floating floors) were evaluated in terms of dynamic stiffness and loss factor. Floor vibrations and radiated sounds generated by simulated impact source were also measured. The results showed that the bakelite was appropriate for simulating concrete slab in the 1:10 scale model, and surface velocity and sound pressure level of concrete slab measured from the scale model showed similar tendencies with the results from in-situ in frequency domain. It was also found that dynamic behaviors of layered floor structures in the 1:10 scale model were similar to those in a real scale. Therefore, the use of 1:10 scale model would be useful for evaluating the heavy-weight floor impact sound insulation of layered floor structures when the frequency-dependent dynamic properties of each material are known.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2014.10a
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• pp.203-207
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• 2014

According to the advanced study, Increase of ceiling air space could cause increase of floor impact sound by air-spring effect. So in this research, we studied the increase of floor impact sound caused by ceiling air space in apartment buildings. At first, we evaluated the change of floor impact noise in the condition of with or without ceiling air-space. And then we installed perforated ceiling systems and glass wool at ceiling area. we expected that perforated ceiling systems could prevent air-spring effect in ceiling space. As a result, ceiling air space caused increasement of floor heavy impact noise about 2~4dB. But perforated ceiling & sound-absorbing materials system could give us reduction of heavy floor impact noise about 3dB. So this systems could be a good alternative to obey national regulations, because it can reduce heavy impact noise additional to floating floor systems.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.1145-1148
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• 2007

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material, which has the most to do with the floor impact sound reduction. The resilient materials available in Korea include EPS (Styrofoam), recycled urethane types, EVA (Ethylene Vinylacetate) foam rubber, foam PE (Polyethylene), glass fiber & rock wool, recycled tire, foam polypropylene, compressed polyester, and other synthetic materials. In this study, we tested floor impact sound reduction characteristic to a lot of kinds of resilient material. The result of test showed that the amount of the heavy-weight impact sound reduction appeared by being influenced from this dynamic stiffness of resilient material. The dynamic stiffness looked like between other resilient materials, a similar to the amount of the heavy-weight impact sound reduction was shown.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.18 no.8
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• pp.886-895
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• 2008

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material have a close relation with the floor impact sound reduction. In this study, to examine the relationship between dynamic stiffness and lightweight impact sound level, the dynamic stiffness and floor impact sound level of 51 resilient materials were measured. The impact sound level of each of these resilient materials, whose dynamic stiffness was measured, was measured before and after installation, and the level difference (${\Delta}L$) was analyzed. The result of test showed that the dynamic stiffness of resilient materials decreased, the lightweight impact sound level also decreased, and there was a correlation between the dynamic stiffness and the lightweight impact sound, especially in the low frequency domain.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2008.04a
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• pp.830-834
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• 2008

Resilient materials are generally used for the floating floors to reduce the floor impact sound. Dynamic stiffness of resilient material, which has the most to do with the floor impact sound reduction. The resilient materials available in Korea include EPS (Styrofoam), recycled urethane types, EVA (Ethylene Vinylacetate) foam rubber, foam PE (Polyethylene), glass fiber & rock wool, recycled tire, foam polypropylene, compressed polyester, and other synthetic materials. In this study, we tested floor impact sound reduction characteristic to a lot of kinds of resilient material. The result of test showed that the amount of the Light-weight impact sound reduction appeared by being influenced from this dynamic stiffness of resilient material. As the decreasing dynamic stiffness of resilient material, the impact sound reduction amount is increased, especially in the low frequency domain.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.24 no.6
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• pp.483-492
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• 2014

Uncomfortable feelings of occupants by indoor floor impact noise in a residential building are not accurately represented by the floor impact noise from a standard impact source. It is due to the characteristics of standard impact sources, which are different from the impact forces produced by occupants. It varies significantly by impact source, and it is not easy to be replicated for testing. As a result, the indoor floor impact noise under different acoustic conditions cannot be directly compared. Using frequency response function(FRF), which represents the input-output relationships of a dynamic system, it is possible to examine the characteristics of the system. Especially, FRF can predict the response of a linear dynamic system subjected to various excitation. To determine the relationship between impact force and the corresponding response of dynamic system in residential building, the acceleration response of a concrete slab and the floor impact noise in the living room, produced by bang-machine and rubber-ball excitation, were measured. The test results are compared to the estimates based on FRF and impact force spectrum.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.10a
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• pp.258-260
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• 2010