• 한국생산제조학회지
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• 제22권4호
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• pp.673-679
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• 2013

This study investigates the strength durability of an automotive front bumper subjected to vibrations during driving. Through structural analyses,the maximum equivalent stresses of models 1 and 2 were found to be 187.09 and 278.4 MPa, respectively. The maximum deformations of models 1 and 2 were 1.3772 and 2.675 mm, respectively. As model 1 shows less deformation than model 2, itis stronger than model 2. Models 1and 2 show natural frequencies within 230 Hz as the range of the maximum harmonic response frequency. Models 1 and 2 have maximum amplitude displacements of 0.105 and 0.154 mm at critical frequencies of 159 and 110 Hz, respectively. As model 1 has a higher critical frequency than model 2, it has more strength durability than model 2. This study result can be effectively utilized for the design of a front bumper by investigating prevention against damage and its strength durability.

• 한국기계가공학회지
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• 제17권3호
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• pp.28-33
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• 2018

The automotive front bumper guard is the most important part of the vehicle for protecting the life of driver when a traffic accident happens. In order to ensure safe driving, this part must possess sufficient strength and durability. This study was carried out with structural and fatigue analyses by designing front bumper guard models. After the lowest value for maximum total deformation and equivalent stress was found through structural analysis and the highest value for fatigue life was found for all three models, it was shown that the type C front bumper guard model was the most suitable for application to a real car. The strength property and durability of the optimum design were determined through this study's results.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2008년도 춘계학술대회 논문집
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• pp.175-176
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• 2008

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2009년도 춘계학술대회 논문집
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• pp.199-202
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• 2009

In roll forming process, a sheet metal is continuously progressively formed into a product with required cross-section and longitudinal shape, such as a circular tube with required diameter, wall-thickness and straightness, by passing through a series of forming rolls in arranged in tandem. Tn this process, each pair of forming rolls installed in a forming machine play a particular role in making up the required cross-section and longitudinal shape of the product. In recent years, that process is often applied to the bumper rail in the automotive industries. In this study, a optimal Front Bumper Beam manufacturing technology, model deign and proper roll-pass sequences can be suggested by forming number of roll-pass and bending angle. And also effects of the process parameters on the final shape formed by roll forming defects were evaluated.

• 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.

• 대한기계학회논문집A
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• 제33권5호
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• pp.502-507
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• 2009

Curvature extrusion process has several advantages in comparison to the conventional extrusion and bending process. In the curvature extrusion, the extruded part is directly bent during extrusion. Therefore, it does not need additional bending process after extrusion. In the curvature extrusion process, it is possible to produce curved extruded products that have a constant or various curvatures. It is essential that we predict the curvatures of the extruded product to meet the required curvatures. This paper proposed a theoretical model that can predict the curvature of extruded product produced by the curvature extrusion process. Using the proposed model the movement of guide tool that causes the bending of extruded product was controlled to produce the required curved automotive Al bumper back beam. The effectiveness of the proposed prediction model and the movement of guide tool were verified by the FE analysis and curved extrusion experiment.

• 한국ITS학회 논문지
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• 제16권5호
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• pp.85-95
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• 2017

본 논문의 목적은 트럭과 보행자의 충돌사고에서 트럭의 중량, 속도와 범퍼 높이가 보행자 전도거리에 미치는 영향을 분석하고, 나아가 이를 이용한 보행자 전도거리에 대한 모형식을 제시하는 데 있다. 이를 위해 교통사고 재현 프로그램인 PC-crash를 이용하여 트럭의 중량을 5t, 15t, 25t으로 적용하고, 각 트럭의 앞 범퍼 하단 높이를 0.3m부터 0.6m까지 0.1m씩 높여감과 동시에 트럭의 속도를 10km/h부터 100km/h까지 10km/h씩 높여가며 실험하였다. 트럭의 속도와 범퍼 높이는 보행자 전도거리에 유의한 변수로 확인되었고, 트럭 중량은 보행자 전도거리에 유의하지 않은 변수로 나타났다. 또한 다중회귀분석을 이용하여 제시한 모형식은 조정된 $R^2$ 값이 93.3%로 매우 우수한 설명력을 가지는 것으로 나타났다.

• 해양환경안전학회지
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• 제20권3호
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• pp.285-291
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• 2014

This study applied regression analysis to evaluate the impact of hourly average congestion calculated by bumper model in the congested area of each passage of each port on the peak time congestion, to suggest the model formula that can predict the peak time congestion. This study conducted regression analysis of hourly average congestion and peak time congestion based on the AIS survey study of 20 ports in Korea. As a result of analysis, it was found that the hourly average congestion has a significant impact on the peak time congestion and the prediction model formula was derived. This formula($C_p=4.457C_a+29.202$) can be used to calculate the peak time congestion based on the predicted hourly average congestion.

• Composites Research
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• 제35권5호
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• pp.317-321
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• 2022

본 연구에서는 머신 러닝을 통해 하중 유형에 따른 구간을 나누어 각 하중 유형에 강한 적층 각도 순서가 배치되는 PIC 설계 방법이 범퍼 빔에 적용되었다. 머신 러닝을 적용하기 위한 학습 데이터의 입력 값과 라벨은 각각 전체 요소 중 일부인 참조 요소의 좌표와 하중 유형으로 정의되었다. 좌표 값을 나타내는 방법인 2D 표현 방법과 3D 표현 방법을 비교하기 위하여 각각의 방법으로 학습 데이터 생성 및 머신 러닝 모델이 학습되었다. 2D 표현 방법은 유한요소 모델을 각 면으로 나누고 그에 따른 학습 데이터 생성 및 머신 러닝 모델을 학습시키는 방법이며, 3D 표현 방법은 유한요소 모델 전체에서 학습 데이터를 생성하여 하나의 머신 러닝 모델을 학습시키는 방법이다. 머신 러닝 모델의 성능에 영향을 미치는 하이퍼파라미터는 베이지안 알고리즘을 통해 최적 값으로 튜닝되었으며, 튜닝 된 모델 중 k-NN 분류 방법이 가장 높은 예측률과 AUC-ROC로 나타났다. 그리고 2D 표현 방법과 3D 표현 방법 중 3D 표현 방법이 더 높은 성능을 보였다. 튜닝 된 머신 러닝 모델을 통해 예측된 하중 유형 데이터가 유한요소 모델에 매핑되었으며, 유한요소 해석을 통해 비교 검증되었다. 3D 표현 방법의 머신 러닝 모델로 설계된 PIC 방법이 강도 측면에서 더 우수함이 검증되었다.

• 자동차안전학회지
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• 제10권2호
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• pp.6-12
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• 2018

Optimized section shape of aluminum bumper backbeam for enhancing the front high speed crashworthiness was investigated. Front body analysis model of a convertible vehicle was built up and parameter studies were carried out with changing the inner rib shape and the section thickness distribution. First an inner rib shape displaying most efficient structural performance was selected. Next, for the selected section the effect of section thickness combination was examined. Also, a light weighed backbeam section displaying crash performance over the current design was suggested. Finally RCAR front low speed impact analyses were carried out for the optimized models.