• 한국소음진동공학회논문집
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• 제22권10호
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• pp.940-948
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• 2012

In Korea, researches on the exposure assessment of the hand-transmitted vibration started from the mid-90, however, they were performed in the limited industries such as auto-assembly plants and the evaluation of the vibration was mostly conducted by ISO 5349(1986). Therefore, it was necessary to assess hand-transmitted vibration levels of workplace such as ship building/repairing industry or mining industry where occupational injuries are largely occurred and to evaluate the vibration levels using revised ISO 5349(2001). The SVAN 948 Four Channels Sound & Vibration Analyser was used for the measurement. The workers using a chain saw were exposed to 1.7~2.8 $m/s^2$ of daily vibration level. Workers using a rock drill in a coal mining were exposed to the highest vibration acceleration among workers and the levels were 7.1~10.8 $m/s^2$. Vibration levels of grinders were different according to the types of grinders. The hand-transmitted vibration of 3 types of grinders were measured and the levels were 3.3~11.1 $m/s^2$. Workers using a impact wrench were exposed to 1.5~1.6 $m/s^2$ of vibration. Out of 20 kinds of machines, only 4 tools provided the information of vibration acceleration on the instructions. In addition, the current condition of workplace to control vibration was not much different from the past because there are no vibration exposure limit.

• 한국산업보건학회지
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• 제6권1호
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• pp.1-16
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• 1996

This study was conducted at an automobile assembly line located in Kyonggi-do, Korea from January 16 to February 28, 1995. The purposes of this study were to assess worker exposures to hand-arm vibration and the performance of gloves for reduction of vibration. The exposure to vibration was measured using to the ISO 5349(1986) method. Vibration acceleration and frequency spectra for each tool were determined on-line replicating actual working conditions and analyzed together with exposure time for evaluating individual worker exposure. Eight pneumatic hand tools, 60 workers exposured to hand-arm vibration, and three pairs of gloves were involved in this study. Results are summarized as follows. 1. Dominant frequencies of vibration for all tools(n=8) measured in this study ranged from 250 Hz to 800 Hz. 2. There was no significant correleration between dominant frequencies and free running speed (p>0.05). 3. Total predicted exposure times of using impact, hammer type did not exceed 40 minutes, but metal finish task, using grinder and sander exceeded 40 minutes. Total exposure time affected significantly the frequency-weighted, 4 hr equivalent acceleration. 4. Predicted prevalence and observed exposure period data were compared in workers(n=60), according to ISO 5349. In this results, 23(50.0 %) and 24(48.07 %) persons exceeded the mean latency periods for vibration-induced white finger(VWF) at 10 % (n=46) and 50 % (n=52) standards, respectively. On the basis of ISO equation, mean latent periods for VWF were 3.23, 4.72 years at 10 %, 50 % standards, respectively. 5. Reduction of vibration by gloves was evaluated. Since impact pneumatic tools produced low frequency vibrations, conventional gloves did not provide any protection. Gloves A and C amplify somewhat the signal at frequency below 400 Hz; the attenuation increases progressively by frequency to reach 18 dB ($7.94{\times}10^{-6}m/s^2$) at 1,000 Hz, slightly worsening Glove B did not provide any protection and made the situation slightly worse. However, since they make the hands warm, the occurrence of vibration-induced white fingers may be reduced.

• Journal of Biosystems Engineering
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• 제33권4호
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• pp.224-229
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• 2008

This study was aimed to minimize the impact force and vibration transmitted to the transporting materials from the trailer and wheel shaft by installing the leaf spring suspension device at the space between the wheel shaft and frame of power tiller trailer. The developed trailer equipped with leaf spring suspension device was compared to the existing trailer without suspension device, in order to identify the vibration absorption effect of the leaf spring. The results of this study could be summarized as follows; (1) The length and the maximum bending amount of the leaf spring were designed as 1,000 mm and 42 mm, respectively, considering the possible space for installing at below the trailer. When 4 leaf springs were installed on both wheel shafts, the allowable maximum load was identified as 9,418 N. (2) The average vibration accelerations for the frequency less than 20 Hz, where the severe transporting loss could be represented, were $0.017\;m/s^2$ and $0.133\;m/s^2$ for the developed and the existing trailer, respectively, showing the vibration absorption effect of about 87%. And the average vibration accelerations on the driver's seat for the frequency less than 20 Hz were $0.01\;m/s^2$ and $0.20\;m/s^2$ for the developed and the existing trailer, respectively, which showed the similar vibration absorption effect. (3) The change of the average vibration accelerations for the frequency from 20 Hz to 80 Hz showed the similar tendency with the result for the frequency less than 20 Hz, but the effect for developed trailer was reduced slightly. And the effect of vibration absorption for the above 80 Hz was reduced highly. However, by installing the leaf spring suspension device at the trailer, the low frequency below 40 Hz, which could affect on transporting loss severely, could be reduced highly. (4) The maximum vibration acceleration for the frequency less than 20 Hz were $0.027\;m/s^2$ and $1.267\;m/s^2$ for the developed and the existing trailer, respectively. And the change of maximum acceleration between 20 Hz and 120 Hz was showed similar tendency with the result for the frequency less than 20 Hz, but the width of change was reduced highly.

• 터널과지하공간
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• 제16권2호
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• pp.179-188
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• 2006

발파작업시 발생하는 진동 소음은 주변에 존재하는 보안물건에 손상을 입힐 수 있다. 또한, 사람 및 가축에게 정신적으로 피해를 줄 수 있다. 그래서 피해가 예상되는 보안물건의 특성을 고려하여 허용 진동 소음 기준을 설정하여 관리하고 있다. 특히, 어패류는 수중에서 생활하기 때문에 지표면에서 사육되는 동물보다 더욱 진동에 대하여 민감하게 작용하는 것으로 알려져 있다. 본 논문의 현장에서는 발파지점으로부터 약 840m정도 떨어진 지점에 대규모 장어 양식장(이하 양만장)이 존재하고 있다. 그래서, 현장 발파작업시 진동 소음으로 인한 피해가 우려된다. 본 논문에서는 발파 작업을 수행하기 전 설계단계에서 실규모 시험발파를 수행하여 양만장의 발파진동 소음을 측정하였다. 그 결과 발파소음은 설정한 허용기준 이내로 나타났다. 그러나 발파진동이 허용기준을 초과하였다. 따라서, 발파진동에 대해서는 기존의 경험적 방법을 통해 영향검토를 수행하였다. 그리고 새로운 3차원 수치해석방법을 통해검증하였다. 이 검토과정을 간략히 서술하였다. 그리고 양만장과 같이 발파진동 소음에 민감한 보안물건 주변 발파설계시의 발파진동 영향검토 방법을 제안하였다. 또한 발파진동 소음제어 설계방법을 소개하고자 한다.

• 한국지반환경공학회 논문집
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• 제16권12호
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• pp.5-12
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• 2015

발파소음은 충격음이기 때문에 인체에 갑작스런 충격을 주며, 발파진동과 같은 경우에는 지반을 따라 진동이 이동하여 인근 주변의 노화된 건물, 가축과 인체에도 큰 피해를 끼칠 수 있다. 본 연구에서는 광산 굴착 시 발생하는 발파영향이 인근지역에 미치는 영향에 대하여 분석하였다. 연구대상 지역의 지반현황을 파악하기 위해 지질조사, 현장시험과 실내시험 등의 지반조사를 수행하였다. 발파진동소음에 대해서는 국내 외 적용사례와 각 기관별 허용기준을 비교하여 현장조건에 가장 적합한 기준을 설정하였다. 발파영향을 검토하기 위해 발파진동 추정 식은 현장에서 시험발파를 수행하여 측정된 발파진동 값을 활용하였다. 발파진동 추정 식을 활용한 영향원의 검토는 발파지점을 보안물건(농장, 민가 등)으로부터 최단거리로 정하여 보안물건에 미치는 영향을 검토하였다. 또한 3차원 수치해석을 수행하여 발파진동 영향검토를 수행하였다. 3차원 수치해석은 동적 발파하중에 대한 구조물의 거동을 해석하기 위해 시간이력해석을 수행하였으며, 3방향에 대한 발파진동 값을 구하였다. 시험발파에 따른 발파진동 추정 식을 이용한 발파진동 영향원 검토 결과와 발파영향에 대한 3차원 수치해석 값을 비교 분석한 결과, 유사한 결과 수치를 확인하였다.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2009년도 추계학술대회 논문집
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• pp.643-646
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• 2009

This study was conducted to simulate the influence of vibration associated with cycling on the body. In this simulation the human model that the riding on a bicycle which have suspension and non-suspension front forks was used. And to arouse impact two kind of bump, 50mm height of radical raised spot and 150mm height of slow raised spot, were used. The vertical displacement of head, the vertical acceleration of head and the torque of neck joint were analysed. The results say that the function of shock absorbing was grater when passing though a 50mm height of radical raised spot then a 150mm height of slow raised spot.

• 한국건축시공학회:학술대회논문집
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• 한국건축시공학회 2015년도 추계 학술논문 발표대회
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• pp.177-178
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• 2015

Various vibration caused by construction vehicles and equipment movement, rock blasting, and crushing obstacle occurs inevitably in construction sites. In this study, we measured the impact of vibration by blasting rock at construction sites, rock crushing, concrete crushing. The measuring instrument was installed in adjacent buildings and observed that blasting vibration differs depending on the charge weight, blasting distance, and the measuring position. The observation was maintained by allowable peak particle velocity standard according to each standards and references.

• 교육녹색환경연구
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• 제9권3호
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• pp.34-40
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• 2010

In this study, vibration characteristics of reinforced concrete slab in large span educational facilities were evaluated. A 21.75m X 14.4m full scale reinforced concrete slab specimen was constructed with pre-flex hybrid beams. Vibrations were generated by three different methods such as free falling method of a 6kg sand bag, a 70kg person walking method and impact method by impulse hammer. Vibrations were generated more than 3 times at single location. Vibration characteristic data were collected by SA390 signal analyzer machine at 5 different locations.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2007년도 추계학술대회논문집
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• pp.1459-1462
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• 2007

In this study, vibration characteristics of concrete slab were investigated through FEM analysis. Four different floor plans with the floor area of $100{\sim}130m^2$ were chosen to be analyzed. Boundary conditions of two dimensional finite element models were determined based on the modal test results. Results showed that mode shapes were formed somewhat different according to the floor plan and the contribution of 1st mode on the floor vibration is generally the highest. Through the transient analysis, it was also found that floor plan, expecially connection of the living room with the kitchen, affected the vibration acceleration levels.

• Structural Engineering and Mechanics
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• 제4권3호
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• pp.209-226
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• 1996

One of the major divisions in the mathematical modelling of a tubular structure is to include the effect of the transverse shear stress and rotary inertia in vibration of members. During the past three decades, problems of vibration of tubular structures have been considered by some authors, and special attention has been devoted to the Timoshenko theory. There have been considerable efforts, also, to apply the method of spectral analysis to vibration of a structure with rectangular section beams. The purpose of this paper is to compare the results of the spectrally formulated finite element analyses for the Timoshenko theory with those derived from the conventional finite element method for a tubular structure. The spectrally formulated finite element starts at the same starting point as the conventional finite element formulation. However, it works in the frequency domain. Using a computer program, the proposed formulation has been extended to derive the dynamic response of a tubular structure under an impact load.