• Maxillofacial Plastic and Reconstructive Surgery
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• v.42
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• pp.22.1-22.6
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• 2020

Introduction: Facial fractures (FFs) occur after high- and low-energy trauma; differences in associated injuries and outcomes have not been well articulated. Objective: To compare the epidemiology, management, and outcomes of patients suffering FFs from high-energy and low-energy mechanisms. Methods: We conducted a 6-year retrospective local trauma registry analysis of adults aged 18-55 years old that suffered a FF treated at the Santa Barbara Cottage Hospital. Fracture patterns, concomitant injuries, procedures, and outcomes were compared between patients that suffered a high-energy mechanism (HEM: motor vehicle crash, bicycle crash, auto versus pedestrian, falls from height > 20 feet) and those that suffered a low-energy mechanism (LEM: assault, ground-level falls) of injury. Results: FFs occurred in 123 patients, 25 from an HEM and 98 from an LEM. Rates of Le Fort (HEM 12% vs. LEM 3%, P = 0.10), mandible (HEM 20% vs. LEM 38%, P = 0.11), midface (HEM 84% vs. LEM 67%, P = 0.14), and upper face (HEM 24% vs. LEM 13%, P = 0.217) fractures did not significantly differ between the HEM and LEM groups, nor did facial operative rates (HEM 28% vs. LEM 40%, P = 0.36). FFs after an HEM event were associated with increased Injury Severity Scores (HEM 16.8 vs. LEM 7.5, P <0.001), ICU admittance (HEM 60% vs. LEM 13.3%, P <0.001), intracranial hemorrhage (ICH) (HEM 52% vs. LEM 15%, P <0.001), cervical spine fractures (HEM 12% vs. LEM 0%, P = 0.008), truncal/lower extremity injuries (HEM 60% vs. LEM 6%, P <0.001), neurosurgical procedures for the management of ICH (HEM 54% vs. LEM 36%, P = 0.003), and decreased Glasgow Coma Score on arrival (HEM 11.7 vs. LEM 14.2, P <0.001). Conclusion: FFs after HEM events were associated with severe and multifocal injuries. FFs after LEM events were associated with ICH, concussions, and cervical spine fractures. Mechanism-based screening strategies will allow for the appropriate detection and management of injuries that occur concomitant to FFs. Type of study: Retrospective cohort study. Level of evidence: Level III.

• Tribology and Lubricants
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• v.37 no.3
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• pp.112-116
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• 2021

Appropriate friction model usage is important for impact analysis because the relative motions between parts that are in contact for very short durations can vary greatly depending on the friction model. Vehicle seat components that have significant effects on impact analysis are also considered. This paper presents an experimental investigation of various material contact pairs to obtain the friction parameters of the Benson exponential friction model for impact simulation. The Coulomb friction model has limitations for impact analysis because of singularity at zero velocity. Metal/nonmetal materials are prepared, and friction tests are conducted for various sliding speeds, loads, and lubrication conditions. The obtained data are used in the friction model to implement finite element analysis. The parameters of the friction model are obtained by the curve-fitting method. The experimental results show that the friction coefficient with metal/nonmetal contact pairs is stable regardless of the working conditions. The friction model used in this study can also be applied for finite element analysis of the crash conditions, where the friction changes abruptly at the contact interface; the obtained friction parameters are also expected to be more accurate with more precise tests under different working conditions. These results can help improve the accuracy of the finite element analysis.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.21 no.11
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• pp.843-850
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• 2020

The purpose of this study is to evaluate the structural risk and weakness of a railway tank car through nonlinear collision analysis according to overseas collision safety standards. The goal is to propose a crash safety design guideline for railway tank cars for transporting dangerous goods in Korea. We analyzed the buffer impact test procedure of railway freight cars prescribed in EN 12663-2 and the tank puncture test criteria prescribed in 49CFR179. A nonlinear finite element model according to each standard was modeled using LS-DYNA, a commercial finite element analysis solver. As a result of the buffing impact test simulation, it was predicted that plastic deformation would not occur at a collision speed of 6 km/h or less. However, plastic deformation was detected at the rear of the center sill and at the tank center supporting the structure at a collision speed of 8 km/h or more. As a result of a head-on test simulation of tank puncture, the outer tank shell was destroyed at the corner of the tank head when 4% of the kinetic energy of the impacter was absorbed. The tank shell was destroyed in the area of contact with the impacter in the test mode analysis of tank shell puncture when the kinetic energy of the moving vehicle was reduced by 30%. Therefore, the simulation results of the puncture test show that fracture at the tank shell and leakage of the internal material is expected. Consequently, protection and structural design reinforcement are required on railway tank cars in Korea.

• Journal of Auto-vehicle Safety Association
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• v.14 no.4
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• pp.77-83
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• 2022

Occupant behaviors and body contact with vehicle interior parts are main injury mechanism in far-side collisions. In vehicle side impact accident where the crash accident occurs on the opposite side of the vehicle from the a particular occupant, it is exposed in terms of relatively larger lateral motion to interact with the opposite side of the vehicle structure. The challenge of minimizing motions of upper body and injury risk according to a direct contact is a primary occupant protection research. This study has performed a data analysis of real-world accident database extracted from the 2016~2020 CISS database and a parametric investigation of impact angles and occupant kinematics in far-side lateral and oblique impact simulations. A detailed data analysis was conducted to reveal the relationship among the accident and injury data. Database analysis and computational far-side impact results proposed the fundamental vehicle design for safety improvement in far-side collisions.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.5
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• pp.530-537
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• 2016

This study investigates frontal crashes, analyzes the driver's action related to the change of the collision direction and determines the severity of (bodily injury). This study was conducted from August, 2013, to January, 2014, and the data for the car damage and human body damage were collected by emergency medical teams. In terms of data collection, we collected the accident vehicle, crash direction, body damage, etc., based on the Korea In-depth Accident Study (KIDAS) and Injury Severity Score (ISS). We used Minitab 17 and SPSS 22.0 to do the frequency analysis and ANOVA. In the analysis results, the prevalence of frontal collisions was 55.8% and mostly occurred in the 12 o'clock direction. In the analysis of the frontal crash direction according to age, the average ages for the 11, 12 and 1 o'clock directions were $46.46{\pm}13.47$, $44.43{\pm}13.40$ and $52.46{\pm}12.04$, respectively, so the older age drivers had a high probability of the accident occurring in the 1 o'clock direction. In the analysis of men's frontal collision direction according to age, the average ages in the 11, 12 and 1 o'clock directions were $47.10{\pm}13.88$, $45.24{\pm}13.78$ and $55.73{\pm}13.38$, respectively, so older aged men had a high probability of having collisions in the 1 o'clock direction. However, the statistical analysis of the frontal crash direction according to age in women didn't show any meaningful trend. When comparing the ISS according to age of the men and women in the collision direction, the men were less likely to have a 12 o'clock collision when $ISS{\geq}9$ and more likely to have a 1 o'clock collision when ISS<9. As a result, frontal crashes are more likely to occur in the 12 o'clock direction and the ISS decreases because the likelihood of frontal crashes in the 1 o'clock direction increases with increasing age. Therefore, when men recognize that they are heading for a 12 o'clock direction collision, they try to steer to the left to reduce the body damage.

• Journal of Korean Society of Transportation
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• v.34 no.1
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• pp.29-42
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• 2016

Speeding is an important factor in traffic safety. Speed not only affects crash severity, but is also related to the possibility of crash occurrence. This study presents results from an analysis of 27,968 speed violation cases collected from 36 red light and speed enforcement cameras at signalized intersections in the city of Cheongju. Data included details of their violation history such as speeding tickets within a recent 3-year span and their demographic characteristics. The goal of this analysis is to understand the correlation between speed violations and various factors in terms of humans, vehicles and road environments. This study used descriptive statistics and Binary Logistics Regression(BLR) analysis with SPSS 20.0 software. The major results of this study are as follows. First, speed violations occurred at rural and suburban area. Second, about 25.6% of the violators committed to more than 20km/h over a speed limit. Third, the difference between speed violators and normal drivers clearly appeared in location of intersection(urban/rural/suburban area), gender and age. Finally, a statistically significant model(Hosmer and Lemeshow test: 11.586, p-value: 0.171) was developed through the BLR.

• The Journal of The Korea Institute of Intelligent Transport Systems
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• v.10 no.1
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• pp.1-15
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• 2011

The RLC systems is one of the intelligent transportation systems that has gained a nation-wide support for last decades and being installed to discourage motorists from running the red lights at signalized intersections. It is taken for granted that the RLC will provide motorists with increased safety, so that their installments are always justifiable. However, in order to acquire more efficiency and wider supports from the general public in future RLC installments, an improved methodology for analyzing the effects of the RLC systems is required. In order to satisfy this requirement, this research performed the following tasks. First, the number of signal violations after the RLC systems were investigated in order to check its resulting effects. Second, the number of crashes after the RLC systems were collected and compared with the number of signal violations. Third, a statistical analysis was carried out to develop the relationships between the signal violations and the crashes based on negative binomial distribution. The analysis revealed that the number of crashes has a close relationship with the RLC placement, traffic volume, vehicle speed, the number of phases, and the number of lanes for major approaches. Finally, based on the results found in this analysis, this research presents a methodology for analyzing the safety effects of placing the RLC that should be of service when investigating the economic consequences of the RLC systems.

• Journal of Auto-vehicle Safety Association
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• v.10 no.4
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• pp.7-12
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• 2018

Injury mechanisms of lower extremity injuries in motor vehicle accidents are focused on fractures, sprains, and contusions. The purpose of this study is to evaluate the analysis of lower extremity injury mechanism in occupant motor vehicle accident by using Hospital Information System (HIS) and reconstruction program, based on the materials related to motor vehicle accidents. Among patients who visited the emergency department of Wonju Severance Christian Hospital due to motor vehicle accidents from August 2012 to February 2014, we collected data on patients with agreement for taking the damaged vehicle's photos. After obtaining the verbal consent from the patient, we asked about the cause of the accident, information on vehicle involved in the accident, and the location of car repair shop. The photos of the damaged vehicle were taken on the basis of front, rear, left side and right side. Damage to the vehicle was presented using the CDC code by analytical study of photo-images of the damaged vehicle, and a trauma score was used for medical examination of the severity of the patient's injury. Among the 1,699 patients due to motor vehicle crashes, 88 (5.2%) received a diagnosis of lower extremity fracture and 141 (8.3%) were the severe who had ISS over 15. Nevertheless during 19 months for research, it was difficult to build up in-depth database about motor vehicle crashes. It has a limitation on collecting data because not only the system for constructing database about motor vehicle crash is not organized but also the process for demanding materials is not available due to prevention of personal information. For accurate analysis of the relationship between occupant injury and vehicle damage in motor vehicle crashes, build-up of an in-depth database through carrying out various policies for motor vehicle crashes is necessary for sure.

• Proceedings of the Korean Institute of Information and Commucation Sciences Conference
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• 2008.05a
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• pp.805-808
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• 2008

In this paper, it was performed the analysis on various intersection acoustic patterns for detection rate improvement of accident sound detection system : an acoustic pattern analysis on general traffic noise, an acoustic pattern analysis on engine noise, an acoustic pattern analysis on obstruct factors for accident sound detection system. There are remarkable differences between the acoustic patterns of traffic noise and accident sound, and we most consider the acoustic patterns when we compose the accident traffic detection system by acoustic because there is error range of 20[dB] according to the volume of traffic in intersection.

• 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.