• 한국안전학회지
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• 제28권5호
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• pp.1-4
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• 2013

The main objective was to design and develop a prototype robot system for assessing slip resistance. The developed robot system will be able to be used for stochastic nature of friction in the whole workplace. The second objective was to evaluate its operating condition in the laboratory, using a dreg sled type slipmeter(BOT-3000) as reference device. It was found that COF(Coefficient of Friction) measured with robot system was similar to that of BOT-3000 when sliding velocity was reached at 0.2m/s. The robot system might be the more promising one than any traditional measurement devices. A further evolution of prototype devices, as well as the development of test methods for that's various applications, is to be started in forthcoming studies.

• 산업기술연구
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• 제26권A호
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• pp.47-54
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• 2006

To improve passenger safety, seat belt systems with pre-tensioner that tightens seat belt webbing using explosive just before collision are widely used these days. Even though seatbelt must not unlatched without passengers' operation. explosive power of pre-tensioner can cause unlocking of a buckle. To prevent the unlocking, an anti-g mass that blocks displacement of the release button has been attached to the buckle. In this study, the dynamics and statics of locking mechanism associated with operation of anti-g buckle has been theoretically investigated, and important design variables that affect the operation of anti-g buckle have been identified. Through the total seat belt system's dynamic simulation using force and displacement inputs obtained from seat belt sled test, design of the proposed anti-g buckle has been validated.

• 한국자동차공학회논문집
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• 제8권3호
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• pp.139-150
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• 2000

Although a number of neck injuries are generated, the data which quantify the kinematic response of the human head and cervical spine in low-speed rear-end automobile collisions is very limited. On this problem, just few in vitro experimental research or some experimental research using dummy on neck injury by rear-end collision was conducted, thus systematic research is requested on full scale injury mechanism. An occupant model for the response of the occupant subject to rear-end collision using commercial dynamics package DADS was developed. Developed model shows more close agreement with the experimental data compared with the MADYMO simulation results for the cases of ${\delta}V=16$ kph in sled test. For the case of ${\delta}V=8$ kph and 33.5 kph with production seat, model also shows its reliable response compared with experimental results using Hybrid III and Hybird III with RID.

• 한국자동차공학회논문집
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• 제11권4호
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• pp.79-85
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• 2003

The child restraint system is blown to be excellent to reduce child occupant injury in frontal collisions. The effects of the child restraint system are experimently investigated according to FMVSS 213. A sled simulator is utilized with varying restraint types such as 2point, 3point seat belts, forward-facing types and booster types of child restraint systems. The head and chest injuries for various cases are evaluated based on industrial standards. Also, the maximum displacements of the head and the knees are measured by film analysis. Using the results of the test, the effects of the child restraint system is discussed and reduction of child occupant injury is pursued.

• 대한의용생체공학회:의공학회지
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• 제20권1호
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• pp.21-27
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• 1999

최근 들어 많은 관심에 대상이 되고 있는 동차 사고시 어린이 승객의 부상현상을 해석하기 위하여 범용 동력학 패키지인 DADS를 이용하여 3세 어린이 모델을 개발하였다. 모델은 모두 14개의 요소들과 12개의 조인트로 구성 시켰으며 부스터를 장착한 시트에 3점식 벨트를 체결한 형태로 개발되었으며 썰매를 이용한 전방 충돌 시뮬레이션 결과 기존의 더미를 이용한 실험 결과와 일치하는 응답 특성을 얻을 수 있었다.

• Composites Research
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• 제36권4호
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• pp.253-258
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• 2023

교통수단의 발전은 이동이 불편한 장애인들의 이동권 보장을 실현하였지만 차량사고시 발생할 수 있는 장애인 탑승객의 안전 향상은 일반 승객좌석에 비해 낮다고 할 수 있다. 특히 갑자기 발생할 수 있는 후방 추돌 사고의 경우 장애인 탑승객의 머리와 목 부상에 취약한 것이 현실이다. 이에 본 연구에서는 휠체어 운송 차량의 후방 추돌 시 차량내 장애인 탑승객의 머리와 목 상해지수 개선을 위해 headrest를 관상면으로 3등분한 multi-layer headrest foam이 제안되었다. 간이 모델을 통한 저속 후방 추돌 해석을 통해 foam의 다양한 압축 특성을 부여하기 위한 stress scale factor의 범위가 선정되었으며, 해당 범위를 parameter로 지정하여 GA최적화가 수행되었다. 최적화결과를 통해 layer의 압축 특성에 따른 HIC와 NIC간의 상간관계 분석이 이뤄졌으며, HIC는 Front layer, NIC는 Mid layer의 압축 특성에 가장 민감하게 반응하였고 Rear layer의 압축 특성은 가장 낮게 나타났다. Validation model에 일반headrest와 최적화된 multi-layer headrest를 각각 배치하여 저속 후방 추돌 sled test 해석을 수행하였으며, 일반headrest대비 multi-layer headrest에서의 HIC와 NIC가 낮게 도출되었다. multi-layer headrest에서의 압축 거동 역시 명확하게 나타나 multi-layer headrest가 일반headrest대비 머리와 목의 상해지수 개선에 효과적인 것이 검증되었다.

• 한국안전학회지
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• 제28권6호
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• pp.73-78
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• 2013

The purpose of this study was to evaluate three kinds of slipmeters (BOT, BPT, English XL) used on-site floor with ASTM F2508 which is comprised of four different standard surfaces(polished granite, glazed porcelain, vinyl composite tile ;VCT, and ceramic tile). ASTM F2508 has two criteria that decide which slipmeter is appropriate or not. The evaluated slipmeters were dreg sled, articulated sturt, and pendulum strike type. The test results revealed that two kinds of slipmeters(BOT, BPT) successfully ranked all four standard surfaces and differentiated among standard surfaces with varying degrees of slipperiness. Nevertheless, the measured value with BOT on the VCT, which was reported as slippery floor in previous study, was higher than its threshold(0.6). Although some slipmeter satisfy two criteria of ASTM F2508, they can underestimate the slip potential. So, another criteria is needed so as to reduce this problem. English XL couldn't properly measure slipperiness under the two kind of floors(glazed porcelain, VCT). So the slider of English XL was modified in order to meet two criteria of ASTM F2508.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2007년도 춘계학술대회A
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• pp.1009-1014
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• 2007

To improve passenger safety, seatbelt systems with pre-tensioner that tightens seatbelt webbing using explosives just before collision are widely adopted. Even though seatbelt must not be unlatched without passenger's operation, release of a buckle due to explosion of pre-tensioner takes place in some situations resulting in serious injury to passengers. To prevent the unintended unlocking, a pendulum like part called anti-g mass is attached to the buckle to block displacement of release button. In this study, the unlocking conditions of anti-g buckle when pre-tensioner explodes has been theoretically investigated. Through multibody model of the seatbelt system incorporating every detailed part of the buckle, dynamic analysis of the seatbelt system with pre-tensioner has been performed including the driver's body model that interacts with seatbelt system. The simulations results has been validated through actual sled test with driver dummy and the seatbelt system.

• 한국안전학회지
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• 제27권5호
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• pp.179-184
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• 2012

This study was performed to find out the measurement criteria of slip resistance from analysis of human gait and slips. Many kinds of slip resistance testers were developed based on mechanical friction testers. But, there are, as yet, no unambiguous slip resistance measurement methodologies and generally accepted safety criteria or safety thresholds for estimating slipping hazard exposures. Also, there are variety of measuring conditions between those testers. The measurement criteria should be tested within the range of human slipping conditions observed in biomechanical studies. It's results should clearly consider whether the devices reflect the human slipping conditions. In this study a dragsled type friction tester, which was constructed in accordance with ISO 15133 basically, was used. Test conditions were set in order to determine the range of measurement criteria. It is shown that drag velocity should be more than 1 m/s, acceleration be more than 10 $m/s^2$, contact time be less than 0.1sec, and contact pressure be within 350~400 kPa.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2008년도 춘계학술대회논문집
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• pp.622-625
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• 2008

SIL-based optical disk drive will be promising candidate of next-generation storage devices. However, a near-field optical disk drive requires the robustness to external shock because of extremely small gap between SIL and media. Especially, high-level shock damages permanently to SIL and it makes difficulties in general application. To study the likelihood of failure, the shock analysis must be performed over all others. This research explores the dynamic characteristics of rotating disk through FEM which is compared to analytical solution and experimental modal analysis. We also develop the finite element model of an optical disk drive, which includes rubber mounts, sled base, rotating disk and pickup assembly, and simulate the shock response.