• 자동차안전학회지
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• 제9권2호
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• pp.20-25
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• 2017

KNCAP is a program to evaluate the automobile safety, providing consumer vehicle safety assessment results. The safety evaluation tests are Frontal Impact, Offset Frontal Crash, Side Crash, Side Pole Crash, Rear Impact. This is the study of the offset frontal impact safety evaluation. Currently, IIHS is performing a small overlap test. NHTSA plans to implement the oblique moving deformable barrier test. Euro-NCAP plans to implement a mobile frontal impact test. Simulation is used to compare occupant behavior and injury. We have investigated whether the introduction of the test at KNCAP is necessary. The dummy model used in the simulation was the 50th percentile male Hybrid III dummy.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 1997년도 춘계학술대회논문집; 경주코오롱호텔; 22-23 May 1997
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• pp.146-152
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• 1997

This paper deals with a study of striker type impact hammer drill for improving the drilling performance. The study was performed through a numerical simulation of the impact hammer mechanism, an experimental comparison of the numerical simulation results and an optimization of the impact mechanism. The numerical model of the impact hammer drill takes into account the striker motion and the effects of the pressure in the cylinder as well as the friction acting on the striker. The equation of motion is solved with the pressure equation in the cylinder and the friction force. At the moment of impact, an ideal impact model that uses restitutiion codfficient is used to calculate the sudden change of the striker motion. The impact force numerically simulated shows a good agreement with the experimental results and thus, the validity of the numerical model is proven. Based upon the proposed model, an optimization was performed to improve the impact force of the hammer drill. The objective function is to maximize the impact force and the design variables are striker mass, frequency of piston, bit guide mass, cylindrical diameter and dimensions of the mechanism components. Each design variable and some other conditions that are essential to maintain normal operation of the hammer drill are considered as constraints. The optimized result shows remarkable improvement in impact force and an experimental proof was investigated.

• 환경영향평가
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• 제8권3호
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• pp.13-22
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• 1999

Tidal flow and water quality were simulated in this paper to assess environmental impact caused by pier construction projects in Onsan harbor system. The Surfacewater Modeling System (SMS) was applied to the Onsan harbor system, where coastal reclamation and dredging were planned to build the piers. A finite element mesh was constructed and refined to cover the complicated geometry of the Onsan harbor and the proposed reclamation area. The time variable change of tidal height at harbor inlet was given as an input condition to tidal simulation. The water quality simulation was based on the discharge rate of suspended solids at the reclamation area. The simulation results have shown reasonable agreements with real situations in both tidal flow and water quality. According to the proposed plan, tidal flow and water quality were predicted during and after the pier construction. The tidal simulation study showed that there would be no discernible change of tidal current in the harbor except for the dredged area. The water quality simulation, however, predicted that suspended solids would increase significantly near the reclaimed and dredged areas during construction.

• 한국도로학회논문집
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• 제12권4호
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• pp.197-202
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• 2010

차선을 벗어난 승용차가 기초에 강결된 표지판 지주에 충돌할 경우 차량이 받는 충격과 변형은 탑승자의 안전을 위협하게 되므로 분리지주를 쓰는 것이 일반적이다. 국도에서 $1200mm{\times}1200mm$의 단일노선표지에 사용되는 직경 101.6mm, 두께 4.0mm의 강관지주가 기초에 강결되었을 때와 Clip형 분리장치를 갖는 경우에 대한 820kg-50kg-정면 충돌 시 차량과 지주의 거동을 LS-DYNA 시뮬레이션을 통하여 비교 분석하였다. 분리식 지주 충돌 시뮬레이션 결과는 동일한 조건의 충돌실험 결과와 비교하여 신뢰도를 높였다. 강결된 원형지주에 대한 충돌 시뮬레이션 결과 탑승자 안전지수(THIV, PHD)와 차량의 변위가 탑승자의 안전을 위협하는 수준으로 나타났으나 Clip형 분리장치를 갖는 지주에 대한 충돌 시뮬레이션 결과 충돌 시 지주의 분리로 감속도가 현저히 줄어들어 안전한 것으로 확인되었다.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2002년도 춘계학술대회 논문집
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• pp.353-356
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• 2002

In vehicle accidents, the rolling, pitching, and yawing which are produced by collisions affect the motions of vehicle. Therefore, vehicle behavior under impact situation should be analyzed in three-dimension. In this study, three-dimensional vehicle dynamic equations based on impulse-momentum conservation principles under vehicle impact are introduced for simulation. This analysis has been performed by the real vehicle impact data from JARI and RICSAC. This study suggested each system modeling such as suspension, steering, brake and tire as well as the appropriate vehicle behavior simulation model with respect to pre and post impact.

• 한국안전학회지
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• 제16권1호
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• pp.9-17
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• 2001

The purpose of this research is to analyze the impact resposes(impulsive stress and strain etc.) of anisotropic materials subjected to the low-velocity impact. For this purpose, a beam finite element program based on modified higher-order beam theory for anisotropic materials are developed and used to simulate the dynamic behaviors [contact force, displacement of ball and target, strain(stress) response histories] according to the changes of material property, stacking sequence, velocity and dimension etc.. Test materials for simulation are composed of $[0^{\circ}/45^{\circ}/0^{\circ}/-45^{\circ}/0^{\circ}]_{2s} and [90^{\circ}/45^{\circ}/90^{\circ}/-45^{\circ}/90^{\circ}]_{2s}$ stacking sequences. Finally, the results of this simulation are compared with those of wave propagation theory and then the impact responses and wave propagation phenomena are investigated.

• 한국자동차공학회논문집
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• 제15권2호
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• pp.135-142
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• 2007

MADYMO human model with the detail neck was used to investigate the reaction force of neck and neck injury from rear impact directions. In the validation simulation, head acceleration, thorax acceleration and the global kinematics of the head and neck were correlated well with experimental data. Acceleration data from three 15 km/h low speed car rear impact pendulum tests(rear-end, offset, oblique) were used to simulate the model. In the simulation results, the reaction force on the facet joint and discs in the oblique rear impact were higher than rear-end, offset rear impacts. Further research is still needed in order to neck injury analysis about different crash parameters.

• 한국안전학회지
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• 제18권4호
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• pp.1-7
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• 2003

The front-end side members of vehicles(spot welded hat and double hat shaped section members) absorb most of the impact energy in a case of front-end collision. In this paper, specimens with various spot weld pitches have been tested with a high impact velocity of 7.19m/sec(impact energy of 1034J). The axial impact collapse simulation on the sections has been carried out to review the collapse characteristics of these sections, using an explicit finite element code, LS-DYNA3D. Comparing the results with experiments, the simulation has been verified; the energy absorbing capacity is analyzed and an analysis method is suggested to obtain exact collapse loads and deformation collapse modes.

• Journal of Mechanical Science and Technology
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• 제19권7호
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• pp.1424-1431
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• 2005

In this study, head injury by impact force was evaluated by numerical analysis with 3-dimensional finite element (FE) model. Brain deformation by frontal head impact was analyzed to evaluate traumatic brain injury (TBI). The variations of head acceleration and intra-cranial pressure (ICP) during the impact were analyzed. Relative displacement between the skull and the brain due to head impact was investigated from this simulation. In addition, pathological severity was evaluated according to head injury criterion (HIC) from simulation with FE model. The analytic result of brain damage was accorded with that of the cadaver test performed by Nahum et al.(1977) and many medical reports. The main emphasis of this study is that our FE model was valid to simulate the traumatic brain injury by head impact and the variation of the HIC value was evaluated according to various impact conditions using the FE model.

• Structural Engineering and Mechanics
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• 제82권2호
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• pp.233-244
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• 2022

Following a loss of control, the impact against a road barrier in a turn predominates among the most severe motorcyclist accidents. These road restraint devices can be equipped with a motorcycle screen, the function of which is to restrain the rider and minimize the consequences of the impact in terms of the severity of injuries. The performance of these screens is evaluated by the European normative procedure EN1317-8, which specifies the test conditions, based on one or two configurations. In practice, however, these impact conditions are very diverse, difficult to extrapolate from accident analysis and therefore poorly investigated. This study is interested in improving knowledge of these impact conditions in terms of impact speed, impact angle and particularly position of the rider. A finite element model has been developed to simulate the dynamic behavior of the rider from loss of control to impact on the screen. Statistical analysis of the results shows a high variability of the impact conditions, in particular with regard to the direction of turn (to the right or to the left). Some improvements are suggested in order to overcome the limitations inherent in standard procedures.