• Journal of the Korean Wood Science and Technology
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• v.30 no.3
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• pp.75-84
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• 2002

In order to find out impact insulation properties, various types of current radiant floor heating systems and light-framed floors that are used in light-framed residential buildings were evaluated for two types of impact sources at the same time. Sound Pressure Level (SPL) was different from each impact sources for those spectrum patterns and peaks. In case of light-framed floor framework, the excitation position and the assumed effective vibrating area have effects on sound pressure level but it is not considerable, and Normalized SPL was reduced for each frequency by increasing the bending rigidity of joist. The mortar layer in the radiant heating system had relatively high density and high impedance, therefore, it distributed much of the impact power when it was excited, and reduced the Normalized SPL considerably. Nevertheless, Increasing a thickness of mortar layer had little influence on SPL. Ceiling components reduced the sound pressure level about 5~25 dB for each frequency. Namely, it had excellent sound insulation properties in a range from 200 to 4,000 Hz frequency for both heavy and lightweight impact sources. Also, there was a somewhat regular sound insulation pattern for each center frequency. The resilient channel reduced the SPL about 2~11 dB, irrelevant to impact source. Consequently, current radiant floor heating systems which were established in light-framed residential buildings have quite good impact sound insulation properties for both impact sources.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.12 no.8
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• pp.573-580
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• 2002

Generally the ceiling frame of apartment house is made of wood. But the wood frame has several problems due to the natural properties such as distortion by shrink, low fire resistance and material loss in the construction field. And it has some defections in sound insulation performance. Therefore it is necessary to develop a new method that can be used as a ceiling frame. This study aims to analyze and to compare the sound insulation characteristics against the floor impact sound between wood ceiling frame and M-bar frame which is made of steel. The results of this study are like these. M-bar frame is more effective than wood ceiling frame in sound insulation. And sound absorbing or sound insulation materials which can be Put on gypsum board are helpful to improve floor impact sound insulation performance.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2005.11a
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• pp.946-949
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• 2005

In this paper, influence factors on dynamic properties of floor impact noise insulation materials are suggested. For this purpose measurements on the dynamic stiffness and the loss factor of resilient materials are carried out by Korea standard (KS F 2868) according to the change of density, thickness, design pattern, and composition of materials. As a result the values of dynamic stiffness was decreased at high density and thick thickness, and that of loss factor was increased at low density. For dynamic properties, the pattern of lattice and waffle type material is better than that of plat type, and the mixed composition of materials is better than the composition of double layer materials at same thickness.

• Elastomers and Composites
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• v.49 no.2
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• pp.95-102
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• 2014

The noise between floors of apartment has been hot issue nowadays. In order to improve the noise insulation performance, we proposed the antivibration rubber system which can be applied to the floor system for sound insulation. Among various types of elastomer, butyl rubber showed the good aging characteristic, low rebound resilience and high damping factor. Thus, the butyl rubber was selected as a basic rubber for antivibration rubber system. The effects of type and loading amounts of carbon black on antivibration properties of butyl rubber were studied. The increase of surface area and the content of carbon black resulted in high bound rubber fraction, high mechanical property, low rebound resilience, and high damping factor of butyl rubber. Based on the results of this study, the new antivibration rubber was prepared and applied to the floor system for sound insulation. The impact sounds of floor system proposed in this study were 40 dB and 43 dB in cases of light weight and heavy weight impact sound, respectively.

• Elastomers and Composites
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• v.35 no.2
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• pp.138-148
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• 2000

In order to investigate the possibility of EPDM micro cellular pad (MCP) as an impact sound insulation product, we studied static/dynamic properties and vibration transfer characteristics of EPDM MCP depending on shape, thickness, degrees of foaming by using material test system (MTS) and lab scale mock-up test apparatus. Static/dynamic rigidity is increased when shape is simple. thickness and degrees of foaming low. We could see that dynamic stiffness is proportional to the transmissibility of EPDM MCP. When dynamic stiffness is increased, characteristic peak at transmissibility curve moves high frequency range or snows increase of maximum value of transmissibility. For lab scale mock-up test and finite element method, EPDM MCP shows low vibration velocity and superior mode shape to just concrete plus slab structure. We could confirm that possibility of EPDM MCP as a impact sound insulation product is high.

• 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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• 2005.11a
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• pp.942-945
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• 2005

The purpose of this study is to suggest a fundamental data for change of dynamic properties according to the loading time of resilient materials. 18 kinds of resilient materials included 4 representative types were measured at the load time of 24hours and 2hours by the method of Korea standard (KS F 2868) measuring the dynamic stiffness and the loss factor of materials under floating floors. As a result, the dynamic stiffness was increased rapidly in case of expandable polystyrene and rubber materials according to the load time, especially before 2 hours. The loss factor was represented that rubber materials with high elasticity are high, and expandable polystyrene, polyester, poly ethylene materials with low elasticity are low.

• Advanced Composite Materials
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• v.17 no.1
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• pp.25-40
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• 2008

The research and development in soundproof materials for preventing noise have attracted great attention due to their social impact. Noise insulation materials are especially important in the field of soundproofing. Since the insulation ability of most materials follows a mass rule, the heavy weight materials like concrete, lead and steel board are mainly used in the current noise insulation materials. To overcome some weak points in these materials, fiber reinforced composite materials with lightweight and other high performance characteristics are now being used. In this paper, innovative insulation sheet materials with carbon and/or glass fabrics and nano-silica hybrid PU resin are developed. The parameters related to sound performance, such as materials and fabric texture in base fabric, hybrid method of resin, size of silica particle and so on, are investigated. At the same time, the wave analysis code (PZFlex) is used to simulate some of experimental results. As a result, it is found that both bundle density and fabric texture in the base fabrics play an important role on the soundproof performance. Compared with the effect of base fabrics, the transmission loss in sheet materials increased more than 10 dB even though the thickness of the sample was only about 0.7 mm. The results show different values of transmission loss factor when the diameters of silica particles in coating materials changed. It is understood that the effect of the soundproof performance is different due to the change of hybrid method and the size of silica particles. Fillers occupying appropriate positions and with optimum size may achieve a better effect in soundproof performance. The effect of the particle content on the soundproof performance is confirmed, but there is a limit for the addition of the fillers. The optimization of silica content for the improvement of the sound insulation effect is important. It is observed that nano-particles will have better effect on the high soundproof performance. The sound insulation effect has been understood through a comparison between the experimental and analytical results. It is confirmed that the time-domain finite wave analysis (PZFlex) is effective for the prediction and design of soundproof performance materials. Both experimental and analytical results indicate that the developed materials have advantages in lightweight, flexibility, other mechanical properties and excellent soundproof performance.

• Proceedings of the Korea Concrete Institute Conference
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• 2003.11a
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• pp.497-500
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• 2003

The propose of this study is to discover the extrusion lightweight concrete panel mixing by admixture. The standard of water ratio 50% and weight substitution 0%, 10% by Fly-ash. When the products are manufactured, it is used to maintain its form weight substitution and addition among the viscosity agent each Silica-fume and Hydroxy propyl methyl cellulose. The study is basic properties and performances of extrusion lightweight concrete panels. Testing methods was specific gravity, water absorption, resistance to impact, thermal conductivity, and sound insulation.

• Journal of the Korea Institute of Building Construction
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• v.19 no.2
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• pp.105-112
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• 2019

Fine aggregate made of ferronickel slag(FNS) is similar to natural fine aggregates and is used in concrete structures both domestically and abroad, but its applications and research areas are limited. In this research, in order to expand the availability of FNS and improve the performance of cement mortar products, the applicability of FNS on dry mortar for floor was examined. Experimental results show that FNS improves flow of cement mortar because it has low absorption rate, spherical shape, and glassy surface. Also, the high stiffness of the FNS aggregate itself is considered to contribute to the improvement of cement mortar quality such as crack reduction by improving the compressive strength and shrinkage reducing. In addition, when FNS fine aggregate is applied, it was possible to secure the impact sound insulation performance equal to or higher than that of mortar using natural fine aggregate.