• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.222-226
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• 1997

The reproducibility of measured level is a prior condition for the reliable assessment of the sound insulation performance. To review the reproducibility of impact sound level, 20 floors were selected in highrise apartment house, and then impact sound levels of two kinds of typical floors were measured with 10 times in each receiving point. The impact sound insulation class values were derived with a standard tapping machine and bang machine. Inspection of the result showed that smaller scale of the room caused to lower the reproducibility and that the higher values of standard deviation in lower frequency caused to deteriorate the reliability of assesment. Thus to enhance the reproducibility of the impact sound insulation class, greater allowable deviation of measured level is required in lower frequency than in higher one.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2005년도 추계학술대회논문집
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• pp.714-714
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• 2005

This paper presents the modeling and impact analysis for a rotating cantilever beam having a concentrated mass. The concentrated mass takes an impact force during the rotating motion and the transient response of the beam induced by the impact is calculated by applying the Rayleigh-Ritz assumed mode method. The stiffness variation effect caused by the rotating motion is considered in this modeling. The effects of the concentrated mass size, impact position and the angular velocity of the beam on the transient responses are investigated through numerical studies.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2001년도 추계학술대회논문집 II
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• pp.945-950
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• 2001

Floor impact noise has been evaluated by investigating the temporal and spectral characteristics of the noise. The noises generated by different impactors were analyzed to find out whether there is any correlation with the factors of ACF /IACF (Autocorrelation Function/Inter-aural Cross-correlation Function) [1] and Zwicker parameters [2]. Experiments were undertaken to compare the objective and subjective parameters of the floor impact noises generated by a bang/tapping machine, a rubber ball [3], and a walker. As a result, it was found that $\phi$ (0) and IACC extracted from ACF/IACF, and Loudness, Unbiased Annoyance from Zwicker parameters showed high correlation with subjective evaluations of loudness concerning floor impact noises. In addition, it was revealed that jumping is similar to the ball.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2004년도 추계학술대회논문집
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• pp.976-979
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• 2004

The KS of 'Laboratory Measurement of Impact Sound Insulation of Floors' is not established yet. To establish this KS, present conditions of domestic laboratory test facilities for measuring impact sound insulation of floors in laboratory and current researches were reviewed As a result the outline of 'Laboratory Measurement of Impact Sound Insulation of Floors' is suggested.

• Structural Engineering and Mechanics
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• 제68권1호
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• pp.95-101
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• 2018

The low rate of penetration and short lifetime of drilling bit served as the most common problems encountered in hard formation drilling, thus leading to severe restriction of drilling efficiency in oil and gas reservoir. This study developed a new local impact drilling method to enhance hard formation drilling efficiency. The limitation length formulas of radial/lateral cracks under static indentation and dynamic impact are derived based on the experimental research of Marshall D.B considering the mud column pressure and confining pressure. The local impact rock breaking simulation model is conducted to investigate its ROP raising effect. The results demonstrate that the length of radial/lateral cracks will increase as the decrease of mud pressure and confining pressure, and the local impact can result in a damage zone round the impact crater which helps the rock cutting, thus leading to the ROP increase. The numerical results also demonstrate the advantages of local impact method for raising ROP and the vibration reduction of bit in hard formation drilling. This study has shown that the local impact method can help raising the ROP and vibration reduction of bit, and it may be applied in drilling engineering.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2003년도 추계학술대회논문집
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• pp.917-917
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• 2003

The auditory experiments based on the subjective annoyance responses were undertaken for the establishment of the adverb modifiers of the heavy-weight impact noises. The standard heavy weight impact noise, impact ball noise and adult walking noise were recorded by dummy head at a newly-built apartment and were presented to the subjects by headphones. The levels of the three impact noises were varied from 30 to 60㏈(A) and the subjects matched one of the adverb modifiers to each level of the noise sources. As a result, seven scale modifiers were established and the intervals between the modifiers were found as equal. In addition, it was found that the lower annoyance noise limits for the heavyweight impact, impact ball and walking were 40-45㏈ (L$\sub$I, Fmax. AW), which is 6㏈ lower than in the previous study. The background noise level was as low as 21㏈(A) in the test booth, therefore, the testing conditions need to be concerned for evaluation of floor impact noise.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2014년도 추계학술대회 논문집
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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.

• 한국음향학회지
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• 제26권6호
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• pp.235-242
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• 2007

공동주택의 바닥충격음 측정 및 평가는 주로 입주 전에 이루어지고 있으나 실제 충격음 발생은 입주 후 커튼과 가구와 같은 중량물이 설치되어 있는 조건이므로 입주 전 후 음원세대(음원실)와 수음세대(수음실)의 상황은 다르다고 할 수 있다. 본 연구에서는 음원실에 가구 등과 같은 하중 설치에 따른 중량충격음 변화정도를 파악하기 위하여 바닥충격음 시험동과 현장에서 활하중($200kg/m^2$) 설치 전 후의 음원실 바닥슬래브 하부 진동가속도레벨 및 수음실 충격음레벨 변화를 측정하였다. 측정결과 하중설치를 통하여 진동가속도레벨 및 충격음레벨이 다소 저감되었으나 큰 영향은 받지 않는 것으로 나타났으며, 슬래브의 공진주파수도 변화하지 않았다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 추계학술대회논문집; 한국과학기술회관; 6 Nov. 1997
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• pp.339-344
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• 1997

Samsung Ltd. has developed a new-type cab mount for specific use on construct ion machinery subjected to strong vibration and multi-directional impact force. These all make it possible to achieve an excellent damping effect over a wide frequency range against large amplitude vibration as well as excellent insulation against small-amplitude vibration. This new mount make lower vibration and noise levels while increasing riding comfort at the same time. Characteristics of Cab mount were optimized through computer simulation, advanced bench testing, ODS testing, and a real equipment offroad testing.

• 화약ㆍ발파
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• 제28권1호
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• pp.1-10
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• 2010

채광을 위한 발파작업 시 발파진동 및 비석에 의한 광주의 피로현상에 의해 주변에 위치한 광주의 변형 및 파괴가 발생될 수 있으며, 이로 인해 채굴공동의 붕락현상이 발생되기도 한다. 본 연구는 대규모 갱내 채굴공동의 효율적인 안정성 유지를 위해, 갱도 굴착에 따른 발파 작업 시 비산과의 충돌에 의한 광주의 역학적 특성을 파악하기 위한 것으로써 발파로 인한 광주와 비석의 충돌 시 광주 주변의 지반진동을 비교하였다. 이에 비석의 파쇄입도분석을 실시하였으며, 경험식에 의한 충격진동과 실제 데이터의 회귀분석에 의한 지반진동을 비교하였다. 또한 이것을 수치해석에 의해 분석된 결과와도 비교하였다.