• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.117-120
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• 2007

The floor slabs of building structures are often subjected to the periodic force which is induced by vibrating machines or human activity(walking, jumping, running etc). These periodic forces cause excessive oscillation. In order to examine the dynamic characteristics of floor slabs, the dynamic characteristics test is accomplished. Generally, the Impact Hammer and Dynamic Exciter test is used to dynamic characteristics test. But the Impact Hammer test is not suitable to apply in building slabs. In this paper, It compared the performance of the Exciter and Impact Hammer test for dynamic characteristics analysis of floor slabs.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2007.11a
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• pp.287-290
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• 2007

In this study, the effect of temporal variation of IACC on subjective response to heavy-weight floor impact noise generated by impact ball was investigated. Subjective evaluation was conducted to investigate the effect of temporal variation of IACC on perception of heavy-weight floor impact noise using paired comparison test. The results showed that the effects of SPL and temporal variation of IACC on the annoyance of heavy-weight impact noises were independent and the contribution of SPL was much larger than that of temporal variation of IACC. It was also found that the effect of IACC is larger than temporal variation of IACC comparing to previous study.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2006.11a
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• pp.356-360
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• 2006

Recently, for the purpose of improving the isolation performance of impact noise, many resilient materials have been installed in a residential building. As one of the reduction method for improving the performance of light-weight impact noise, this study is focused on the load condition of floating layer over resilient material. We studied the correlation between the mass or load of the floating layer and the reduction of light-weight impact noise by experiments in reverberation chamber for testing the impact noise. The results show that the reduction of impact noise is improved by increasing the mass per unit area of floating layer until about $140kg/m^2$. But the reduction is not obvious by adding extra mass on the floating layer.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2002.11b
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• pp.468-473
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• 2002

The purpose of this study was to present the possible use of a new standard impactor, the rubber ball(so called, impact ball), and to assess its evaluation method as for heavy-weight impact in multi-story residential buildings, Several experiments were carried out to investigate the effect of the impact on noise propagation in reinforced concrete buildings. Then, the noise from the impact ball was psychoacoustically evaluated. The correlation between the L-value evaluation methods and auditory responses was also investigated. Results show that the ball noise is quite similar to the jumping noise. The noise level of ball is even higher than the bang machine noise, although it has much lower impact force. It was also found that L-indexing seems to bge inappropriate for evaluation of ball noise.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2001.05a
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• pp.59-64
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• 2001

Recently, among those general contractors and construction material production companies in korea, this concept is lively obtained to reduce the floor impact sound. This attempt is continuously tried for developing the floor impact isolation material. However the assesment of the isolation performance is often ignored and even there seems no differences in comparison with the general the isolation performance of the floor impact. This is often occurred for their only respect with the material of the floor impact isolation performance. Therefore, this study analysed the expected problems for site application of currently applied the isolation material and its capacity which as the floor impact reducing material, and presented several major assesment items and checklist which should be inspected in advance of their development or site application.

• 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.

• Journal of KSNVE
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• v.8 no.3
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• pp.513-523
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• 1998

Impact response of a vibro-impact system and its contact mechanism was studied. The vibro-impact system is composed of a small secondary system is constrained to move along a slot of fixed length in a large primary system. The contact mechanism is characterized by its coefficient of restitution. Numerical simulation analysis has been used to determine the time-history and the impact statistics of the primary and secondary systems. Input excitation of the primary system was random, and the responses obtained were the velocities of the primary and secondary system, the closing velocity in time axis and the duration time between impacts. The validity of the numerical simulation method was checked by comparing the results with those obtained by other researchers analytically. It is shown that the results obtained by the nemerical simulation analysis showed a good agreement with those for the analytical method.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2004.05a
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• pp.137-142
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• 2004

The aim of this study is to investigate the characteristics and quantity of the noise reduction by floor coverings. The characteristics on the reduction of the lightweight impact sound level by floor coverings is as follows. The insulation level attained by floor coverings tends to be smaller in actual buildings than in public laboratories. The reduction of the impact sound level to the tape is similar to the method of adhesives. For this reason, the reduction of impact sound level by floor coverings in public laboratories can be utilized to tape. And the reduction of impact sound level by floor coverings is not influenced by the size of specimen except the specific frequency.

• Proceedings of the Korean Society for Noise and Vibration Engineering Conference
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• 2010.05a
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• pp.689-689
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• 2010

Since the apartment was built by Korea National Housing Cooperation in 1961, the amount of its supply has been increased greatly, especially from the late 70's. Recently there are many ongoing studies regarding sustainable construction apartment in Korea, one of the research is developing sustainable apartment that has longer life cycle. Also according as life's quality of residents is upgrading, complain for impact noise and plumbing system noise from upstair or downstair are increasing more and more. To solve this complains, government established impact noise standard as lightweight impact noise of 58dB, heavyweight impact noise of 50dB and presented standard floor system or recognition floor system to satisfy this impact noise standard. So in this study, the aim is to develop dry ondol access floor system for sustainable apartment which have pleasant and quiet life environment.

• Transactions of the Korean Society for Noise and Vibration Engineering
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• v.26 no.4
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• pp.483-491
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• 2016

Precision of theoretical group velocity of waves in shell structures was discussed for the purpose of source localization of loose parts impact in pressure vessels of nuclear power plants. Estimating exact location of loose parts impact inside a reactor or a steam generator is very important in safety management of a NPP. Evaluation of correct propagation velocity of impact signals in pressure vessels, most of which are shell structures, is essential in impact source localization. Theoretical group velocities of impact signals in a plate and a shell were calculated by wave equations and compared to the velocities measured experimentally in a plate specimen and a scale model of a nuclear reactor. The wave equation applicable to source localization algorithm in shell structures was chosen by the study.