• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.5
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• pp.29-34
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• 2005

141,841 car-to-car collision had occurred in 2003, and among the accidents 51,796 were rear-end impact. According to insurance company for loss or damage, more than $60\%$ of rear-end impact victims suffer neck injury. This means at least 31,000 neck injury victims have happened in 2003. More than $97\%$ of the neck injury victims have low severity injury than A.I.S 2. Head restraint, which is designed to limit rearward head movement and equipped on seat, can considerably protect neck from rear-end impact. In this paper we evaluated head restraint geometry and drivers' sitting position according to RCAR standard and carried out low speed volunteer crash test. The crash speed is 4km/h and N.I.C value is used to determine injury probability. Through these research results we can introduce the method to prevent neck injury at rear-end impact.

• Transactions of the Korean Society of Automotive Engineers
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• v.15 no.2
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• pp.135-142
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• 2007

MADYMO human model with the detail neck was used to investigate the reaction force of neck and neck injury from rear impact directions. In the validation simulation, head acceleration, thorax acceleration and the global kinematics of the head and neck were correlated well with experimental data. Acceleration data from three 15 km/h low speed car rear impact pendulum tests(rear-end, offset, oblique) were used to simulate the model. In the simulation results, the reaction force on the facet joint and discs in the oblique rear impact were higher than rear-end, offset rear impacts. Further research is still needed in order to neck injury analysis about different crash parameters.

• Transactions of the Korean Society of Automotive Engineers
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• v.14 no.4
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• pp.181-191
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• 2006

The most common kind of vehicular accident is the low-speed rear-end impact that result in high portion of insurance claims and Whiplash Associated Disorders(WAD). The low-speed collisions have specific characteristics that differ from high speed collisions and must be treated differently This paper presents a simple continuous contact force model for the low-speed rear-end impact to simulate the accelerations, velocities and the contact force as functions of time. A smoothed Coulomb friction force is used to represent the effect of braking, which was found to be significant in simulating low-speed rear end impact. The intervehicular contact force is modeled using nonlinear damping and spring elements with coefficients and exponents. This paper presents how to estimate analytically stiffness and damping coefficients. The exponent of the nonlinear contact force model was determined to match the overall acceleration pulse shape and magnitude. The model can be used to determine ${\Delta}Vs$ and peak accelerations for the purpose of accident reconstruction and for injury biomechanics studies.

• Journal of the Korean Data and Information Science Society
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• v.19 no.2
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• pp.463-473
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• 2008

In this study, we measure damage depth and calculate effective impact speed in case of rear-end collision using real car insurance data. We study the relationship between demage depth and effective impact speed, and present statistical model for these two variables. In our real data study, 3-degree polynomial equation model is better fit to effective impact speed and demage depth than the simple linear model that are estimated in previous other studies. Damage depth is a major factor to see the extent of impact in a car collision, and by using this equation, it is possible to evaluate the severity of driver's injury.

• Transactions of the Korean Society of Automotive Engineers
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• v.7 no.9
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• pp.182-194
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• 1999

Occupant injury in rear end impact is rapidly becoming one of the most aggravating traffic safety problems with high human suffering and societal costs. Although rear end impact occurs at relatively low speed , it may cause permanent disability due to neck injuries resulting from an abrupt moment, shear force , and tension/compression force at the occipital condyles. The analysis is performed for a combined occupant-eat model response, using the SAFE(Safety Analysis for occupant crash Environment) computer program. The computational results are verified by those from sled tests. A parameter study is conducted for many physical and mechanical properties. Seat design has been performed based on the design of experiment process with respect to five parameters; seat-back upholstery stiffness, torsional stiffness of the seat-back. An orthogonal array is selected from the parameter study. A good design has been found from the analysis results based on the orthogonal array. The results show that reductions of stiffness in seat-back upholstery and joint are the most effective for preventing neck injuries.

• Transactions of the Korean Society of Automotive Engineers
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• v.13 no.1
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• pp.132-139
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• 2005

The driving position of head restraints and the relative risk of neck injury were studied in the computer simulation. MADYMO human model with the detail neck model was used to define the magnitude and direction of internal forces acting on the cervical spine during rear-end impact and to determine the effect of the initial position of the occupant's head with respect to the head restraints. Maximum reaction forces were generated during the head contact to the restraint and relatively large forces were generated at each spinal components in lower cervical spine in proportion to backset and height distance increasement.

• Transactions of the Korean Society of Mechanical Engineers A
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• v.29 no.6 s.237
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• pp.913-920
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• 2005

Compared to previous in-vitro test, FE model showed reliable motion patterns. A finite element model of a 50th percentile male neck was developed to study the mechanics of whiplash injury while the rear impacts. The model was consisted of the whole cervical vertebrae including part of occipital, intervertebral discs. which were modeled using linear viscoelastic materials and posterior elements. The sliding interfaces were defined to simulate contact phenomena in facet joints and in odontoid process. All ligaments and atlanto-occipital membrane were modeled as nonlinear bar elements. Only muscle elements were not considered. Motion of each cervical vertebra was obtained from the dynamic simulation with a MADYMO model for 15 km/h $40\%$ rear end offset impacts. Soft tissue neck injury(STNI) was investigated with a developed FE model. In FE model analysis, the high stress was appeared at C3/C4 disc in offset impact. Further research is still needed in order to improve the developed neck FE model for many different crash patterns.

• Transactions of the Korean Society of Automotive Engineers
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• v.24 no.4
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• pp.432-438
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• 2016

Whiplash injuries in low-speed rear-end collisions are the most common injuries and has been a social issue in insurance industry, such as excessive medical claim costs along with exaggerated injuries of victims and treatments from hospitals. According to the Korea Insurance Development Institute reports, the number of claims by rear-end collision was approximately 703,000, which accounts for 53.6 % of the total car-to-car collisions in 2014. Part of the neck injury claims in the Korea car insurance was approximately 28.3 %. Furthermore, approximately 98.4% of the injured persons in rear-end collisions sustained minor injuries under AIS2. In order to improve this situation as well as find out the severity of neck injuries from rear-end collision, the Korea Automobile Insurance Repair Research and Training Center conducted car-to-car rear-end crash tests that striking vehicles(SUV) collided into different sizes of struck-vehicles(small, middle, and large sedan) at the impact speeds of 8 km/h ~ 16 km/h. In order to analyze the whiplash injury, the BioRID-II was seated in each struck-vehicles, and the neck injury criteria(NIC), head contact time, maximum vehicle accelerations, and mean vehicle accelerations were calculated from values from the accelerations of the dummy and the struck-vehicles.

• Transactions of the Korean Society of Automotive Engineers
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• v.21 no.4
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• pp.54-61
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• 2013

Although typically classified as AIS 1, whiplash injuries continue to represent a substantial social problem with associated costs estimated at over $1 billion annually. The primary objective of this study was to determine the effects of seat positions(seatback angle, headrest height) on risk for whiplash injury in very low speed(${\Delta}V$=4~10km/h) rear-end impact. To accomplish this, rear impact seat carriage tests and simulations were conducted using the BioRID-II dummy seated in a mass production seat, which allowed for the adjustment of seatback angle and headrest height. Neck injury criteria(NIC, Nkm) were then compared for different ${\Delta}V$ and seat positions.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.857-858
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• 2010