• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2005.06a
• /
• pp.1376-1380
• /
• 2005

In recent automotive industry, vehicle weight can be reduced by one-step forming of tailored blanks welded with two or more sheets of metal blanks. Tailored blank(TB) welding is a production method for blanks involving welding together materials of different quality, thickness, and coating, and has proved popular in fabrication automotive parts. This paper deals with the forming characteristics of mash seam welded tailored blanks. Using these forming characteristics, the bumper beam was developed using the mash seam welded tailored blank with the different thickness. We performed the forming simulation with respect to strain distribution on blank during the stamping of the bumper rail part. Based on these results, we made some stamping tryouts with selected types of blank designs to investigate the formability of tailored blank with different thickness. During the tryouts, we knew that it was important the BHF(Blank Holding Force). We obtained to reducing 10.5% weight and cost with adapting the bumper beam of automotive component using the tailored blank of mash seam welding.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.5
• /
• pp.228-234
• /
• 2002

The CO$_2$ laser beam irradiation strengthening of 35kgf/mm$_2$ grade steel sheet is investigated to reduce the weight of bumper beam. The increase of tensile strength is dominated by the number of fully penetrated melting lines. The optimal laser irradiation pattern is obtained by 3-point bending test of hat-type specimens. Laser should be irradiated not only on the center specimen densely in the width direction, but also on the edge densely in the longitudinal direction. Local laser strengthening may be effective for the weight reduction of automobile bumper beam.

• Transactions of the Korean Society of Automotive Engineers
• /
• v.20 no.2
• /
• pp.98-102
• /
• 2012

Increasing the fuel economy has been an inevitable issue for the development of new cars, and one of the important measures to improve the fuel economy is to decrease the vehicle weight. In order to obtain this goal, the researches about lighter, stronger and the well impact absorbing bumper impact beam have been studied without sacrificing bumper safety. In this study, the overall weight reduction possibility of rear bumper impact beam could be examined based on the variation of frontal, offset and corner impact crash capability by substituting a ultra high strength steel material (boron steel ) having tensile strength of 1.5 GPa grade instead of conventional steels. In addition, the section variations (open section, closed section, open section with 5 stays) of the bumper impact beam structure were examined carefully. It could be reached that this analysis could be well established and be contributed for design guide and the optimum design conditions of the automotive rear bumper impact beam development.

• Journal of the Korean Society for Precision Engineering
• /
• v.20 no.7
• /
• pp.163-170
• /
• 2003

The back beam for a automotive bumper was roll formed to improve performance, reduce weight and save cost. For the back beams produced by conventional stamping and roll forming, the crashworthiness analyses were carried out by numerical simulation and real impact test. The characteristic properties and applicability of the roll formed back beam are discussed from the results of the analyses.

• Proceedings of the Korean Society for Technology of Plasticity Conference
• /
• 2008.10a
• /
• pp.42-45
• /
• 2008

Recently, aluminum is widely used to reduce the vehicle weight. Aluminum curved extruded products are used for the design of automotive frame parts. This study focuses on the determination of process condition fur automotive bumper beam with various curvatures. In this study, a curvature prediction model has been proposed considering the geometric relationship and the characteristic of the curvature extrusion equipment. Using the proposed model and FE analysis, the appropriated process condition was determined to produce the bumper beam. Finally, curvature extrusion experiment was carried out to verify the effectiveness of the proposed curvature prediction model and the process condition.

• Design & Manufacturing
• /
• v.2 no.4
• /
• pp.32-36
• /
• 2008

Roll forming process for the bumper beam of high strength steel is developed by an experimental method. The size of the bumper beam is reduced to 1/1.8 to save development time and cost. The developed forming rolls are installed in the small three-stage roll forming machine and roll forming experiments are carried out. It is found that the experimental method using small forming machine is effective in developing roll forming process for the bumper beam of high strength steel.

• Proceedings of the Korean Society of Precision Engineering Conference
• /
• 2007.06a
• /
• pp.517-518
• /
• 2007

• Transactions of the Korean Society of Automotive Engineers
• /
• v.10 no.6
• /
• pp.125-132
• /
• 2002

Bumpers are structural components to reduce physical damage to the front and rear ends of a passenger motor vehicle from low speed collisions. Damage assessment and the protectiveness are the commonly used designing criteria but in this study, relative displacements of the bumper are examined. To absorb the crash energy without significant damage to the bumper itself, foam material is installed between fascia and beam. However, it is not easy to predict the exact displacements generated in bumper structures through FEM because the compressive stress-strain curve of a foam material depends on strain rates that deviates significantly on each trial. Under this uncertain condition, a range of displacements is calculated and the optimum design is performed using the design of experiments. The result will be used to find the design that minimizes the weight within displacement constraints. The orthogonal array of L9 is introduced to find the optimum of the design variables that considers the thickness of inner beam, outer beam and stay, This study will suggest the design procedure of a front bumper using the uncertain stress-strain curve of a foam material.

• Laser Solutions
• /
• v.2 no.1
• /
• pp.51-60
• /
• 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.

• Journal of the Korea Academia-Industrial cooperation Society
• /
• v.12 no.3
• /
• pp.1122-1127
• /
• 2011

A bumper beam plays the important role of absorbing the bulk of bumper impact energy, so it is extremely important to determine the bumper beam section during the initial stage of car development process. This paper uses the Intermediate Response Surface Models (IRSM) technique for the bumper beam section optimization. By using this method, the nonlinear impact force-deflection curve is changed to an approximated curve. This can avoid the excessive 3D nonlinear FEM analysis during the optimization process. Then, the accuracy of the IRSM models is examined by comparing their results with those of the 3D nonlinear FEM. Finally it is shown that the proposed approach is effective to design the 2.5mph vehicle bumper section.