• 한국자동차공학회논문집
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• 제17권2호
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• pp.104-111
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• 2009

In this paper, optimization for frontal crashworthiness is carried out for the weight reduction design of an auto-body member with the advanced high strength steels(AHSS) such as 780TRIP and 780DP. The frontal crashworthiness is evaluated in order to optimize thicknesses for the front rail member of the ULSAB-AVC, Thicknesses of the front rail member with AHSS are optimized by comparison of crushing distance, absorbed energy and the deceleration for the auto-body with the response surface methodology. The results demonstrate that the crashworhiness of the front rail member with the optimum thicknesses of the AHSS is similar to analysis results obtained from the ULSAB-AVC project. The results also show that the weight reduction design is performed by substituting the AHSS for conventional structural steels such as 440E in the auto-body members.

• 한국자동차공학회논문집
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• 제4권2호
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• pp.189-197
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• 1996

In this study, the crashworthiness analysis was carried out for the hat type section side rails which had an important role of absorbing the impact energy during frontal crash. In case of a tapered hat type section model, numerical simulation models and test models were designed with varing design variables; welding pitch, taper angle, initiator shape, initiator location. The effect of variation of the design variables was investigated by quasi-static and dynamic test and numerical simulation.

• International Journal of Automotive Technology
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• 제6권5호
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• pp.491-499
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• 2005

There are different types of vehicle impacts recorded every year, resulting in many injuries and fatalities. The severity of these impacts depends on the aggressivety and incompatibility of vehicle-to-roadside hardware impacts. The aim of this paper is to investigate and to enhance crashworthiness in the case of full barrier impact using a new idea of crash improvement. Two different types of smart structures have been proposed to support the function of the existing vehicle. The work carried out in this paper includes developing and analyzing mathematical models of vehicle-to-barrier impact for the two types of smart structures. It is proven from analytical analysis that the mathematical models can be used in an effective way to give a quick insight of real life crashes. Moreover, it is shown that these models are valid and flexible, and can be useful in optimization studies.

• Composites Research
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• 제21권1호
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• pp.22-29
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• 2008

본 논문은 유리섬유 에폭시 면재에 알루미늄 하니컴 샌드위치 복합재가 적용된 저상버스 차체에 대한 정면충돌과 전복에 대한 특성에 대해 연구하였다. 이때 충돌과 전복 해석은 외연유한요소 해석 프로그램인 LS-DYNA3D를 이용하였다. 차체 구조물에 적용되는 적층 복합재 면재에 대해 기계적 특성시험을 통하여 물성을 획득하였고, 직교이방성 특성을 갖는 하니컴 심재의 물성은 유효등가손상 모델을 적용하였다. 저상버스의 충돌 해석은 60km/h의 속도로 정면충돌 사고를 모사하여 해석을 수행하였고, 전복해석은 유럽 안전법규 ECE-R66의 시험 방법을 고려하여 해석하였다. 저상버스의 정면충돌과 전복에 대해 운전자와 승객의 생존 공간 안전성에 관한 결과를 보여준다. 또한, 수정된 Chang-Chang 파손기준식은 충돌과 전복해석에 대한 복합재 구조물의 파손 모드 예측에 추천된다.

• 한국자동차공학회논문집
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• 제10권1호
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• pp.153-161
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• 2002

This paper develops a finite element model for crashworthiness analysis ova small-sized bus. The full vehicle finite element model is composed of 31,982 shell elements,599 beam elements,42 bar elements, and 34,204 nodes. The model uses four material models (such as elastic, elastic-plastic(steel), rigid. and elastic-plastic (rubber) material model) of PAM-CRASH. The model uses four contact types to define sliding interfaces in ten areas. A frontal crash test using an actual vehicle with 30mph velocity to a rigid barrier is carried out. Vehicle pulses at lower part of left and right b-pillar are measured, and deformed shapes of frame and driver seat's lower left area are photographed. A frontal crash simulation using the developed full vehicle finite element model is performed with PAM-CRASH installed in super computer SP2. The simulation is performed with the same conditions as the test. The measured vehicle pulses and photographed deformed shapes from the test are compared to ones from the simulation to validate the reliability of the developed model.

• 한국자동차공학회논문집
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• 제11권3호
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• pp.155-160
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• 2003

For the weight reduction of vehicle body up to 20∼30% compared to the conventional monocoque steel body·.in-white, most automotive manufacturers have attempted to develop the aluminum intensive body-in-white using an aluminum space frame. In this paper, the crush tests and simulations for the aluminum extrusions filled with the structural from are performed to evaluate the collapse characteristics of that light weighted material. From these studies. the effectiveness of structural for is evaluated in improving automotive crashworthiness. In order to improve the improve energy absorption capability of the aluminum space frame body, safety design modifications are performed and analyzed based on the suggested collapse initiator concepts and on the application of the aluminum extrusions filled with structural foam. The effectiveness of these design concepts on the frontal and side impact characteristics of the aluminum intensive vehicle structure is investigated and summarized.

• 한국자동차공학회논문집
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• 제5권2호
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• pp.23-30
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• 1997

Modelling and crashworthiness analysis of simplified vehicle structures with beam element and nonlinear spring element to which axial and bending collapse mecha- nisms are applied are carried out. And on the basis of these analyses, two types of full car modelling and crahworthiness analyses with nonlinear spring and beam element are accomplished. The one is the full car model of which 30% of the structures are modelled with nonlinear spring and beam element, and the other 75% of whole structures. And the results are compared with those of full car analysis with shell element.

• Composites Research
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• 제21권5호
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• pp.15-22
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• 2008

본 논문은 샌드위치 복합재가 적용된 자동무인경전철 차체 구조물의 구조 안전성 및 충돌 안전성 결과에 대해 서술하고 있다. 차체 구조물에 적용된 샌드위치 복합재는 알루미늄 하니컴 심재와 WR580/NF4000 유리섬유/에폭시 적층 복합재 면재로 이루어져 있다. 차체 구조물에 적용되는 적층 복합재 면재에 대해 기계적 시험을 통하여 물성을 획득하였고, 직교 이방성 특성을 갖는 하니컴 심재의 물성은 유효등가손상모델을 적용하였다. ANSYS v11.0을 이용한 유한요소 해석은 JIS E 1105 기준과 ASCE 21-98 기준에 따라서 자동무인경전철 차체의 구조 안전성을 평가하였다. 충돌해석은 외연유한요소 해석 프로그램인 LS-DYNA3D를 이용하였다. 충돌 조건은 강체벽에 10km/h의 속도로 정면충돌 사고를 모사하였다. 또한, 수성된 Chang-Chang 파손기준시은 충돌 후 복합재 구조물의 파손 모드를 평가하는데 추천된다.

• 한국자동차공학회논문집
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• 제20권3호
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• pp.13-19
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• 2012

The fatalities rate for passenger vehicles, vans, and commercial vehicles is 1.23, 1.90 and 2.46 deaths per 10,000 registered vehicles, respectively. This shows that vans and commercial vehicles are vulnerable compare to passenger vehicles. To evaluate the crashworthiness of van and Light Truck Vehicle(LTV), we carried out frontal offset crash test at 64km/h, 40% overlap as per IIHS(Insurance Institute for Highway Safety). The test result show that LTV is very poor to protect occupant at frontal crash cause there is no safety system such as airbag and pretensioner and front end length(distance from front bumper to steering wheel) is short. One of the van rated as the lowest rating even it is equipped with airbag, cause its safety cage was collapsed during the test. This result shows that the structural integrity is very important in terms of occupant protection.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.1156-1161
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• 2008

Nonlinear dynamic analysis is generally used in automobile crash analysis and structural optimization considering crashworthiness uses the results of nonlinear dynamic analysis. Automobile crash optimization has high nonlinearity and difficulty in calculating sensitivity. Recently the equivalent static load (ESL) method has been proposed in order to overcome these difficulties. The ESL is the static load set generating the same displacement field as the nonlinear dynamic displacement field at each time step in dynamic analysis. From various researches regarding the ESL method, it has been proved that the ESL method is fairly useful. The ESL method can mathematically optimize a crash optimization problem through nonlinear analysis and well developed static optimization. The ESL is applied to nonlinear dynamic structural optimization of the automobile frontal impact problem. An automobile bumper is optimized. The mass of the structure is minimized while some constraints are satisfied.