• Journal of the Korean Society of Manufacturing Technology Engineers
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• v.22 no.4
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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.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.17 no.3
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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.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2008.06a
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• pp.175-176
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• 2008

• Proceedings of the Korean Society for Technology of Plasticity Conference
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• 2009.05a
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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.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.2
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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.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.33 no.5
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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.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.16 no.5
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• pp.85-95
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• 2017

This study aims to identify the throw distance in terms of truck weight, bumper height, and speed in a truck and pedestrian collision, and to propose a model for throw distance estimates. For this purpose, a simulation analysis is performed using the PC-crash program with the following experiment conditions: Truck weight of 5t, 15t, and 25t, Bumper height from 0.3m to 0.6m by 0.1m, and speed from 10km/h to 100km/h by 10 km/h. Experimental results show that the truck speed and bumper height are found to be significant factors for pedestrian throw distance, but truck weight is not a significant factor. Also, a regression model is developed for pedestrian throw distance estimate from the multiple regression analysis. The adjusted $R^2$ value of the model is 93.3%, which is very good explanatory power.

• Journal of the Korean Society of Marine Environment & Safety
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• v.20 no.3
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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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• v.35 no.5
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• pp.317-321
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• 2022

In this study, the PIC design method with machine learning that automatically assigning different stacking sequences according to loading types was applied bumper beam. The input value and labels of the training data for applying machine learning were defined as coordinates and loading types of reference elements that are part of the total elements, respectively. In order to compare the 2D and 3D implementation method, which are methods of representing coordinate value, training data were generated, and machine learning models were trained with each method. The 2D implementation method is divided FE model into each face and generating learning data and training machine learning models accordingly. The 3D implementation method is training one machine learning model by generating training data from the entire finite element model. The hyperparameter were tuned to optimal values through the Bayesian algorithm, and the k-NN classification method showed the highest prediction rate and AUC-ROC among the tuned models. The 3D implementation method revealed higher performance than the 2D implementation method. The loading type data predicted through the machine learning model were mapped to the finite element model and comparatively verified through FE analysis. It was found that 3D implementation PIC bumper beam was superior to 2D implementation and uni-stacking sequence composite bumper.

• Journal of Auto-vehicle Safety Association
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• v.10 no.2
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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.