• Journal of Auto-vehicle Safety Association
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• v.6 no.1
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• pp.10-15
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• 2014

Motion Analysis of pedestrian headform was first applied in this paper for the purpose of determining the relationship between stiffness of hood and HIC. Since the analysis of headform movement involves rotation, it has been problematic if analysis of the headform movement is made in local coordinate system only. Correlation of test and simulation is expected to be enhanced through the development of New type of Head Movement Analysis Method.

• Transactions of the Korean Society of Automotive Engineers
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• v.25 no.3
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• pp.374-379
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• 2017

In vehicle to pedestrian accidents, cracks occur in the vehicle laminated glass due to impact of a pedestrian's head. In this study, FMH(Free Motion Headform) was used to experiment on and analyze the crack patterns on a vehicle laminated glass that collides with an adult headform at speeds of 20 km/h, 30 km/h, and 40 km/h, respectively. Applying the acquired experimental data and material property of the vehicle laminated glass to the structural analysis program LS-Dyna, we could develop the FE model of vehicle laminated glass similar to real vehicle laminated glass. We could estimate the head impact velocity and pedestrian's vehicle impact velocity using the Madymo program.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2008.04a
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• pp.573-578
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• 2008

Finite element analysis of impact response of a motorcycle helmet is presented in this paper. The finite element LS-DYNA3D code is used to simulate the impact response of the helmet including of plastic shell, foam liner, and magnesium headform. Since the maximum accelerations at center of gravity of the headform obtained by numerical analysis and experiment agree well, the numerical simulation is proved to be valid.

• Transactions of the Korean Society of Automotive Engineers
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• v.20 no.2
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• pp.64-69
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• 2012

Head injury is one of the most common cause of deaths in car-to-pedestrian collisions. To reduce the severity of such injuries, many international safety committees have performed headform impact test for pedestrian protection. In this paper, an adult headform impactor model is developed based on the finite element (FE) method and validated through the numerical simulation. The skin material of headform impactor is known as polyvinyl chloride skin (PVC) and its material was assumed as viscoelastic. The viscoelastic parameters of headform skin are identified by a series of trial and error methods. The new developed FE adult headform impactor is verified by the drop test and FE JARI adult headform impactor provided by Madymo program.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.1
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• pp.106-115
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• 2007

In this study, first, child headform model was built up, satisfying requirement in the headform validation test. Also, for decreasing both acceleration peak and deformation, a new hood with dome shaped forming in inner panel was investigated. Next, headform impact, complying with draft of EEVC W/G 17, on the central portion of the newly proposed hood were simulated for a steel hood and three aluminum hoods with different thickness for examining the material and thickness effect on HIC value and inner panel deformation. The analysis results explained that aluminum hoods with dome shaped forming in inner panel were highly promising not only for meeting headform safety regulations but also for leading to weight savings. Finally, hood edge design technology in order to reduce pedestrian injury due to the high stiffness of beam type edge and the rigid support, was discussed. Various types of the foam filled edge were designed and their headform safety performance were evaluated. The edge structure with foam filled in upper one third of section exhibited excellent results.

• Transactions of the Korean Society of Automotive Engineers
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• v.16 no.4
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• pp.8-13
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• 2008

Since hundreds thousands of pedestrians are killed or injured in car accidents every year, a variety of research efforts have been performed to protect pedestrians in pedestrian-vehicle crashes. The IHRA reports that injuries on the child head, the adult head, and the adult lower leg/knee are the most critical in the crashes. Identifying the current status of international activities on pedestrian protection, this study, in particular, carries out headform impact test using selected domestic vehicles categorized by three groups - Sedan, SUV (Sport Utility Vehicle), and 1 Box (One Box) Vehicle. According to the valuable findings from the test results, this paper proposes a methodology under which the Korean Technical Regulation for protecting pedestrians in pedestrian-vehicle crashes will be developed.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.5 no.4
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• pp.53-58
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• 2006

IHRA Pedestrian Working Group has investigated and analyzed the current status of pedestrian-vehicle accidents in IHRA member countries. According to the results, European countries and Japan are working on new regulations to improve passive pedestrian protection on passenger cars significantly. Although IHRA proposed pedestrian test procedures, which may provide a basis of technical regulations in the future, further research and development are necessary to refine the procedures. In order to prepare and satisfy the pedestrian protection requirements, domestic passenger vehicles also should be tested. Among various safety-related studies based on accident data analysis, dealing with pedestrian head injury would be considered one of the keen interests. In this study, the pedestrian headform impact test system is developed. The developed system will be useful to carry out validation study of the test procedures through actual tests using sample vehicles, and to explore the car feasibility level prior to the use of the test methods in legislation.

• Structural Engineering and Mechanics
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• v.48 no.5
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• pp.661-679
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• 2013

In this work, the safety performance of a commercial motorcycle helmet already placed on the market is assessed. The assessed motorcycle helmet is currently homologated by several relevant motorcycle standards. Impacts including translational and rotational motions are accurately simulated through a finite element numerical framework. The developed model was validated against experimental results: firstly, a validation concerning the constitutive model for the expanded polystyrene, the material responsible for energy absorption during impact; secondly, a validation regarding the acceleration measured at the headform's centre of gravity during the linear impacts defined in the ECE R22.05 standard. Both were successfully validated. After model validation, an oblique impact was simulated and the results were compared against head injury thresholds in order to predict the resultant head injuries. From this comparison, it was concluded that brain injuries such as concussion and diffuse axonal injury may occur even with a helmet certified by the majority of the motorcycle helmet standards. Unfortunately, these standards currently do not contemplate rotational components of acceleration. Conclusion points out to a strong recommendation on the necessity of including rotational motion in forthcoming motorcycle helmet standards and improving the current test procedures and head injury criteria used by the standards, to improve the safety between the motorcyclists.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.34 no.8
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• pp.1113-1118
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• 2010

It is requested that the interior compartment of a passenger vehicle must be satisfied with the FMVSS201U regulation, FMH impact test. It is needed the design methodology to find the appropriate structure about the FMH impact. When designing the impact-absorbing structure for the FMH impact test, it is to be noted that the impact absorber must have different performance considering the stiffness of the vehicle as the impact position and approach angle of FMH. In this study, an efficient design methodology was developed by using subcomponent collapse simulation instead of conducting full-vehicle simulation, thereby reducing the time and resources spent. Further, this unit-model simulation helps optimize the impact absorbing structure.