• 화약ㆍ발파
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• 제9권3호
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• pp.3-9
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• 1991

On Influence of ground Vibration occured when smoky-chimney is demolished. The Shock Energy by falling down of smoky-ehimney(60m height ) demolition spread mainly to the breaking reinforced concrete and to ground Vibration.

• 대한화약발파공학회:학술대회논문집
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• 대한화약발파공학회 2006년도 추계학술발표회 논문집
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• pp.119-140
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• 2006

발파를 통한 암반 굴착작업은 폭약의 폭발 시 발생하는 충격압과 가스압을 이용하여 암석을 파괴하며, 폭원으로 부터 3차원적으로 전파되어온 충격압에 의한 충격파는 발파에 의한 에너지의 $0.5{\sim}20%$가 탄성파의 형태로 균열대 외부의 지반속으로 전파되면서 공기매체를 타고 전달되는 것이 발파소음이다. 발파소음은 공기의 진동에 의한 음파 가운데 가청범위 ($20{\sim}20000Hz$)의 주파수를 갖는 충격성 소음으로 인체 감응에 의해 영향이 제기되는 것으로, 정신적 고통에 의한 민원발생으로 공사정지, 발파규모 축소 등으로 발파작업에 지장을 주고 있다. 본 연구는 터널발파작업에 따른 발파소음 저감을 위해 현장마다 설치하고 있는 방음시설의 설치시기와 설치방법 그리고 재질에 대하여 현장시공 사례를 통하여 고찰하였다.

• 한국안전학회지
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• 제24권5호
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• pp.6-12
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• 2009

This study performed an experiment for the danger of an electric shock in the human body, which is directly touched or approached to the exposure of buried metals in a leak caused by certain ground faults at a buried cable in street lamp. In the results of the experiment, the dangerous of electric shocks due to the earth specific resistance and wet and submersion of the earth surface represents a high level as the human body is directly touched to the buried metal at a leak point. In addition, it can be seen that the safety of the human body is influenced by the earth specific resistance, separated distance from buried metals, and shape of buried metals at around the leak point.

• 한국안전학회지
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• 제23권6호
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• pp.44-50
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• 2008

This paper presents study on the electric potential distribution when have a short in street lamp. In order to measure electric potential testing ground is built in. A experiment is conducted to simulate dry and submerged situation of street lamp. The street lamp is leaked by artificial means. And electric potential is measured in grounded street lamp and street lamp alone. The results show that touch voltage of grounded street lamp is possible more high than street lamp alone. And the electric shock hazard is high because high electric potential is distributed near submerged street lamp. Also if street lamp is submerged ground is not useful to decrease electric shock hazard.

• 한국군사과학기술학회지
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• 제24권1호
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• pp.70-78
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• 2021

Naval surface ships and submarines could be exposed to non-contact underwater explosion(UNDEX) environment. Equipment installed on the ships and submarines could be damaged by shock load generated by UNDEX environment. Therefore, shock survivability of equipment generally evaluated by shock tests. Ground based shock test machine such as Light weight shock test machine(LVSM) is developed to simulate shock load caused by UNDEX environment. In this study, linear dynamic model of LVSM is proposed and evaluated to improve shock test design procedure. Parameters of the model are decided by optimizing time domain response compared to zero payload experiment. Proposed model is verified by comparing simulation results and test results of maximum payload experiment. Finally, shock test design using the model is described for various test equipment weight.

• 환경영향평가
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• 제20권5호
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• pp.641-649
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• 2011

The ground vibration has effect on the human body and the nearby structure. However, it was very difficult to estimate the damage of structure caused by the vibration. Especially, ground vibration must be estimated on the bottom of structure because it was made up of several mediums. In this study, it was considered about the shock vibration on medium characteristics as calculating the peak particle velocity and analysing the vibration waveform. The results are as follows : Firstly, the correlation coefficient of PPV(Peak Particle Velocity) and SD(Scaled Distance) was very high at the vertical component, which was represented to 0.991 in general ground medium and each 0.989, 0.961, 0.925 in concrete medium. And also, the vibration waveform at the vertical component was very good in all mediums. Secondly, the vibration waveform at the longitudinal component was represented to a great amplitude and phase difference in all mediums. It was considered that the vibration waveform occurred the damping when particle velocity by shock vibration was propagated through other medium. Thirdly, the vibration waveform in concrete medium was represented to variation of amplitude in the order of RC medium, NC=H medium, NC=S medium at the vertical component. It was considered that the particle velocity propagated fast when a medium have a big strength and density.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 추계학술대회논문집
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• pp.734-735
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• 2008

Shock absorber for rotorcraft landing gear should absorb landing impact during landing and isolate vibration to fuselage during taxiing. Double stage oleo-pneumatic shock absorber is known to have better performances than single stage oleo-pneumatic shock absorber. This paper deals with the z-direction translational acceleration at mass center, roil and pitch angular acceleration of fuselage for single and double stage oleo-pneumatic shock absorber at nose landing gear when a 6DOF rigid model is taxiing on the pound.

• 한국안전학회지
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• 제32권2호
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• pp.21-26
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• 2017

According to the data of Korea Occupational Safety and Health Agency, electric shock accidents during recent 11 years exceeded more than 60% in architecture/other and construction work, the countermeasures for safety are required in the harsh environment of a construction site where moving electric machines and equipments are widely used. The establishment of countermeasure for insulation degradation and defect is required, in consideration of increasing trend for accidents caused by defective insulation among low voltage electrical installation each year. The aim of this study is to propose the policy about portable electrical tool standards and/or worker's safety standards for preventing electric shock accidents on safety workings, and is to develop the technology and the safety device to prevent electric shock for accident prevention reduction through experiments. It obtained the followings through this study; statistical data analysis of late about 10 years of electric shock-related industrial accidents analysis and portable electric tools; safety device development of 'device for testing continuous grounding and power shut-down' to prevent electric shock from portable electric tools. Furthermore, developed results and proposal in this study will help to prevent the electric shock accidents from portable electric tools and will be expected the utilization of policy formulation, educational data and field supplement of the safety device, and etc.

• 전기의세계
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• 제29권5호
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• pp.303-311
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• 1980

The hazards of electrical shock are well known, but the conventional ground fault circuit breakers did not provide the statis factory safety for human body. Thus this paper considers the standards of performance that they must meet, and describes the new tripping mechanism the operations and the improvements. The experiment at new G.F.C.I. indicates maximum tripping time 25msec minimum sensitive leakage current 25mA and maximum nonaperation leakage current 15mA.

• 대한기계학회논문집A
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• 제21권8호
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• pp.1250-1258
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• 1997

This paper reports on the development of a new foot for a quadrupedal jointed-leg type walking robot. The foot has 2 toes, one at the front and the other at the rear side, for stable landing on uneven ground by point contact. The toes can move up and down independantly, guided by double-wishbone shaped parallel links which enable the lower leg to rotate with respect to a remote center on the ground surface. The motion of each toe is damped by a hydropneumatic shock absorber integrated in the foot in order to absorb the dynamic landing shock. Furthermore, the new foot can reduce the maximum hip joint drive torque by shortening the moment arm length between the hip joint and the landing force vector on the ground. Intensive experiments were carried out in this study by using a one-leg walking model to investigate the soft landing performance of the foot which could be hardly offered by conventional robot feet such as a flat plate with a gimbal type ankle joint. And it was confirmed that the hip joint torque of the leg walking on the flat surface could be reduced remarkably by using the new foot.