• 한국자동차공학회논문집
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• 제23권1호
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• pp.105-111
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• 2015

Since 2007, Insurance Institute of Highway Safety(IIHS) has conducted the new bumper test using bumper barrier to estimate the repair cost of impacted vehicle. In this study, for the front body FE model of a medium size passenger car analyzes were carried out to optimize the shape of backbeam center reinforcement bracket. First, overlap effect was examined with changing the overlap magnitude and spot welds were added along the backbeam center line for reducing the section shear deformation. Next, for an overlap model design parameter study was performed for the bracket. Thickness effect was examined and an inner reinforcement was added to the bracket. Also, the lower part of bracket was deleted and additionally the bracket length was extended. The results were discussed in terms of backbeam backward deflection, barrier backstop intrusion and weight. Compared with the current design, the final model showed 44.1% bracket weight reduction with 30.0% decrease of backbeam deflection.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2003년도 추계학술발표대회 논문집
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• pp.137-140
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• 2003

Impact of Automotive GMT(Glassfiber reinforced Mat Thermoplastic) Bumper for '5Mhp Barrier Test'was simulated using ls-dyna. The FE model consists of foam which is energy absorber, bumper beam and stay etc. Bumper intrusion and deflection was compared with the experimental results. Effects of uncertainty of material property and deviation of impact velocity were considered and results were compared with those of base design. Effects of number of integration points through th thickness was also investigated.

• 한국자동차공학회논문집
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• 제24권2호
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• pp.191-197
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• 2016

RCAR low speed impact test estimates repair cost of the impacted vehicle. In this study, for a mid-size vehicle front body model, structural performance for RCAR low speed impact were analyzed with changing the bumper stay shape and size. First, for improving the impact load transfer mechanism to side member the stay rear section shape at connecting area with side member was modified and the stay outer was redesigned to be normal to the barrier. Next, the investigation on stay thickness effect was carried out and the performances of several models with different forming shape were compared. The final design showed 13mm decrease in the maximum barrier intrusion distance and greatly reduced side member deformation. Additional analyses explained the validity of the final design.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2000년도 추계학술대회 논문집
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• pp.563-566
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• 2000

Recently vehicle development trend puts emphasis on cost reduction and performance improvement through weight reduction, and safety security to protect passenger and chassis against external impact. Primary factors effected on vehicle safety are chassis structure, chassis system, and safety equipment like bumper. Research in part of weight reduction is proceeding actively about prohibition of over-design and material through optimal design method. Bumper in these factors is demanded two of all factors, safety security and weight reduction. It is the part that prohibits or reduces a physical impact in low speed crash. Bumper is composed of a few parts but this study exhibits the shape of bumper rail has a role on energy absorption of safety security and weight reduction from structure analysis of bumper rail's variable shape surface.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2005년도 추계학술대회 논문집
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• pp.30-33
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• 2005

Although extruded aluminium bumper beam has been commonly used in advanced car makers, there are not so much precedent for it's localization. For the localization of aluminum bumper beam of 7XXX series, benchmarking, material modifications of 7XXX series aluminum alloy, section design of beam, impact analysis had been performed in this study. High fuel efficiency and weight reduction could be achieved by using aluminum bumper beam of which the weight is lighter than that of steel. Moreover, it is expected to reach higher recycling rate by substituting aluminum for steel.

• 한국레이저가공학회지
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• 제2권1호
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• pp.51-60
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• 1999

In this paper, weldability and formability of Tailored-Blank (TB) and the structural impact testing of bump beam were investigated to apply TB to automobile bumper beam. The optimal $CO_2$ laser welding condition for TB of SPFC and SPRC steel plates with different thicknesses was obtained. Before welding, the cross section of butt joint was prepared only by shearing without milling process. Real type bump beam was produced by two kind of forming processes such as roll-forming and press-forming, and the good formability of TB was obtained. Impact test results of bump by using pendulum and barrier were satisfied the impact regulation of bump. Finally. It may be confirmed that laser welded TB is well-balanced material in both weight reduction and production cost of automobile bump.

• 한국정밀공학회지
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• 제17권4호
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• pp.226-232
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• 2000

This paper develops a finite element model for studying the crashworthiness analysis of a mid-size truck. A simulation for a truck frontal crash to a rigid barrier using the model is performed with PAM-CRASH installed in super computer SP2. Full vehicle model is composed of 86467 shell elements, 165 beam elements and 98 bar elements, and 86769 nodes. The model uses four material model such as elastic, elastic-plastic(steel), rigid and elastic-plastic(rubber) material model which are in PAM-CRASH. Frame and suspension system are modeled with 28774 shell elements and 31412 nodes. Cab is modeled with 34680 shell elements and 57 beam elements, and 36254 nodes. Bumper is modeled with 2262 shell elements, and 2508 nodes. Axle, steering shaft, etc are modeled using beam or bar elements. Mounting parts are modeled using rigid bodies. Bodies are interconnected using nodal constrains or joint options. To verify the developed model, frontal crash test with 30mph velocity to a rigid barrier is carried out. In the crash test, vehicle pulse at lower part of b-pillar is measured, and deformed shapes of frame and driver seat area are photographed. Those measured vehicle pulse and photographed pictures are compared those from the simulation to verify the developed finite element model.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2001년도 추계학술대회논문집A
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• pp.489-494
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• 2001

This paper develops a finite element model for frontal crash analysis of a large-sized truck. It is composed of 220 parts, 70,041 nodes and 69,073 elements. This paper explains only major parts' models in detail such as frame, cab, floor, and bumper which affect on crash analysis a lot. In order to prevent penetration not only at a part itself but also between parts, all contact areas are defined using type-36, self-impact type. The developed model's reliability is validated by comparing simulation and crash test results. The results used for model validation are vehicle pulses at B-pillar, and frame and deformation of frame and cab. The frontal crash simulation is performed with the same conditions as crash test. And, it is performed using PAM-CRASH installed in super-computer SP2. The developed model whose reliability is verified may be used as a base to develop a finite element model for occupant behavior and injury coefficient analysis.

• 한국강구조학회 논문집
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• 제13권4호
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• pp.381-393
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• 2001

최근 교통상항은 교통량의 급격한 증가와 차종의 다양성에 그 특성이 있다. 우리나라에서 가장 많이 사용되고 있는 W형 보를 사용한 가드레일은 $14ton-60Km/h-15^{\circ}$ 의 충돌조건에 대하여 구조물의 강성이 충분치 못한 반면에, 보다 현실적인 충돌속도에 대하여 소형차의 탑승자 안전을 충족시키지 못하는 것으로 나타났다. 대형차에 대응하기 위하여 구조물의 강성을 증가시키는 일과 소형차에 대하여 탑승자의 안전을 도모(에너지 소산)해야하는 두 가지의 서로 상반된 목표를 달성하기 위하여, 두께 3.2mm의 강판을 이용한 보의 고무로 만든 충격 흡수재를 이용한 트라이-빔 가드레일 시스템을 고안하여 정적 실내실험, 컴퓨터 시뮬레이션 및 실차 충돌실험을 통하여 거동 및 성능을 조사하였다. 2%의 무게증가로 기존의 W형 보에 비하여 보의 높이가 약 100mm 증가된 트라이-빔(450mm)가드레일 시스템은 범퍼 높이가 다른 다양한 차종에 보다 좋은 수용능력을 보였고 강성과 충격흡수 능력 또한 W-보 가드레일 시스템에 비하여 크게 향상되었다. 그리고 실차 충돌실험을 실시한 결과 NCHRP 350의 Test 3-10 충돌시 성능 요건을 만족시켰다.