• 한국생산제조학회지
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• 제18권5호
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• pp.477-482
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• 2009

This study analyzes the result with dynamic simulation about deformation according to time when a car impacts bollard. These results are shown as followings. The maximum deformation is shown at the lower part of front grass in case of the impact of front or passenger seat but this deformation is shown at the lower part of rear bumper in case of double impact. The maximum equivalent stress is shown at the upper part by the side grass of driver seat at the elapsed time of 0.00075 second after impact in case of the impact of front or passenger seat but this deformation is shown at the front bonnet at the elapsed time of 0.004 second after the additional impact in case of double impact. The maximum total deformation or equivalent stress is shown nearly same in case of the impact of front or passenger seat. But the value of this deformation or equivalent stress in case of the impact of front or passenger seat is shown with 2 times or more than 17% respectively as this value in case of double impact.

• 한국자동차공학회논문집
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• 제11권6호
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• pp.205-212
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• 2003

This paper may provide a basic design data for the safer car seat mechanism and the quality of the material used by finding out the passenger's dynamic behavior when protected by seat belt during collision. A computer simulation with finite element method is used to accomplish this objective. At first, a detailed geometric model of the seat is constructed using CAD program. The formation of a finite element from a geometric data of the seat is carried out using Hyper-Mesh that is the commercial software for mesh generation and post processing. In addition to seat modeling, the finite element model of seat belt and dummy is formed using the same software. Rear impact analysis is accomplished using Pam-Crash with crash pulse. The part of the recliner and right frame is under big stress in rear crash analysis because the acceleration force is exerted on the back of the seat by dummy. The stress condition of the part of the bracket is checked as well because it is considered as an important variable on the seat design. Front impact model which including dummy and seal belt is analyzed. A Part of anchor buckle of seat frame has high stress distribution because of retraction force due to forward motion of dummy at the moment of collision. On the basis of the analysis result, remodeling and reanalysis works had been repeatedly done until a satisfactory result is obtained.

• 한국자동차공학회논문집
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• 제14권5호
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• pp.155-163
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• 2006

Car seat is one the most important element to make comfortable drivability. It can absorb the impact or vibration during driving state. In addition to those factors, it is needed to have enough strength for passenger safety. From energy efficiency and environmental point of view lighter passenger car seat frame becomes hot issue in the auto industry. In this paper, weight optimization methodology is investigated for commercial car seat frame using CAE. Optimized designs for seat frame are developed using commercially available finite element code(ANSYS) and design of experiment method. At first, car seat frame is modelled using 3-D computer aided design tool(CATIA) and simplified for finite element modelling. Finite element analysis is carried out for the case of FMVSS 202 Head Restraint test to check the strength of the original seat frame. Two base brackets are selected as optimized elements that are the heaviest parts in the seat frame. After finite element analysis for the brackets with similar load condition to the previous test optimization technique is applied for 10% to 50% weight reduction. Design of experiment is utilized to obtain optimization design for the bracket based on the modified 50% weight reduction model in which outer shape of the bracket is conserved. Weight optimization models result in the decrease of the strength in spite of weight reduction. The more design points should be considered to get better optimized model. The more advanced optimization technique may be utilized for more parts of the seat frame to increase whole seat frame characteristics in the future.

• 자동차안전학회지
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• 제3권2호
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• pp.5-10
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• 2011

Under the full frontal crash event, seatbelt system is the most typical and primary restraint device that prevents the second impact between an occupant and vehicle interior parts by limiting the forward motion of an occupant in the vehicle occupant packaging space. Today's restraint systems typically include the three-point seat belt with the pretensioner and the load limiter. A pretensioner preemptively tightens the seat belts removing any slack between a passenger and belt webbing which leads to early restraint of a passenger. After that a load limiter controls level of belt load by releasing the belt webbing to reduce occupant injurys. In this study, load characteristics of load limiters are optimized by the computer simulation with a MADYMO model for a frontal impact against the rigid wall at 56kph and then we suggest performance requirements. We derived optimum load characteristic from the results using four vehicle simulation models represented by the vehicle. Based on the results, we suggest the performance from the results of the second optimization using the simulation considering the design and the standardization. Finally, the performance requirements is verified by the sled tests including the load limiter device for the full vehicle condition.

• 자동차안전학회지
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• 제10권3호
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• pp.32-37
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• 2018

Recently, the driver can be assisted by the advanced active safety devices such as ADAS from road traffic risks. With this system, driver and passenger may freed from can driving tasks or kept eyes on forward direction while on the road. Help from adoptive cruise control, auto parking and newly develped automated driving vehicles technologies, the driver positions will vary significantly from the current standard driver position during the travel time. On this hypothesis, the objective of this study is analyze the behavior and injuries of drivers in the event of frontal impact under these abnormal driver position. Based on the KNCAP frontal impact testing method, this simulation matrix was set-up with dummies of 5 th tile female Hybrid III dummy and 50 th tile male Hybrid III dummy. The small sedan type passenger car was modeled in this simulation. The series of simulation was performed to compare the injuries and behaviour of each dummy, varying the seating status and seat position of each dummy.

• 한국자동차공학회논문집
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• 제5권4호
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• pp.142-151
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• 1997

In order to reduce passenger injuries in side collisions, car makers are developing a side impact airbag system while Volvo has already adopted. This study examines dummy injury reduction effect of a side airbag system using full car side impact simulation according to FMVSS 214 test procedure. The simulation result without side airbag shows a good correlation with test data. The folded airbag simulation is carried out to check main design factors. Through the simulation with side airbag module integrated in the seat frame, it is found that the side airbag system provides a substantially enhanced protection for car occupants in side collisions.

• 한국소음진동공학회:학술대회논문집
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• 한국소음진동공학회 2000년도 춘계학술대회논문집
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• pp.1710-1715
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• 2000

Estimation of damping ratio for vibration signals measured on the passenger car's seat is useful for the objective evaluation of impact harshness in car. The vibration signal is a transient signal represented by many coupled modes of suspension system. Wavelet transform automatically decouples these modes in the time-frequency domain. Damping ratios for decoupled modes are obtained by logarithmic treatment for the Wavelet transformed signal. The objective evaluation using Wavelet transform has been well corresponded with subjective evaluation done by skilled engineers.

• 한국산학기술학회논문지
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• 제13권3호
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• pp.994-1001
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• 2012

승차감이나 안전에 관련된 부분 중 하나인 자동차 시트는 차량 주행시 전달되는 충격이나 진동을 적절하게 흡수하여 승객에게 안락성을 제공한다. 또한 이러한 여건을 만족시키면서 승객의 안전을 보장하는 충분한 강성과 강도를 가져야 한다. 자동차 시트는 2가지의 모델로 설계를 하고 구조 해석을 하였다. 그 결과, 시트 백 프레임의 모델(b)가 (a)보다 적은 변형량과 피로 수명을 보였고. 모델의 중앙에 해당되는 허리부분에서 가장 많은 변형량과 파손 가능성을 보였다. 고유진동수를 적용한 진동해석에서, 모델(a)의 경우는 모델의 바깥쪽에서 안쪽으로 변형이 되었고, 모델(b)의 경우는 모델의 안쪽에서 바깥쪽으로 변형이 되었다. 전반적으로 모든 면에서 모델(b)가 (a)보다 구조적으로 안전하다고 사료된다.

• 한국철도학회논문집
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• 제6권1호
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• pp.15-20
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• 2003

The computer simulation techniques were adopted to evaluate the effects of seating positions of passenger under various accident scenarios. The baseline of computer simulation model was tuned by the sled impact tests which conducted under the upright and standard seating positions. This study shows the effect of relative velocity between occupant and struck vehicle while occupant is impacted to a front seat's seatback. Although, base on the current accident scenarios, The KHST is performed well enough to protect average adult male occupants. However, Results from the tests indicate small size occupant or higher impact speed may cause sever neck and femur injuries.

• 한국철도학회:학술대회논문집
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• 한국철도학회 2002년도 추계학술대회 논문집(I)
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• pp.60-65
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• 2002

The computer simulation techniques were adopted to evaluate effects of seating positions of passenger under the various accident scenarios. The baseline of computer simulation model was tunned by the sled impact tests which conducted under the upright and standard seating positions. This study shows the effect of relative velocity between occupant and struck vehicle while occupant is impacted to a front seat's seatback. Although, base on the current accident scenarios, KHST is performed well enough to protect average adult male occupants. However, Results from the tests indicate small size occupant or higher impact speed may cause sever neck and femur injuries.