• Journal of Trauma and Injury
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• v.28 no.3
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• pp.98-103
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• 2015

Purpose: To compare injury sustained and severity of child occupant according to the types of safety restraint systems in motor vehicle crashes. Methods: This was a retrospective observational study. The study subjects were child occupants under the age of 8 years who visited a local emergency center following a motor vehicle crash from 2010 to 2014. According to safety restraint: child restraint systems (CRS), belted, and unbelted, we compared injuries sustained and injury severity using the maximal Abbreviated Injury Scale (MAIS) and Injury Severity Score (ISS), and analyzed the characteristics of severe injuries (AIS2+). Results: Among 241 subjects, 9.1% were restrained in CRS, 14.5% were only belted, and 76.3% was unbelted at the time of the crashes. Fourteen had severe injuries (AIS2+), all of whom didn't be restrained by CRS. Injuries in face and neck were the highest in unbelted group, and MAIS and ISS were the lowest in CRS group. Conclusion: Among safety restraint systems for child occupant in motor vehicle crashes, the CRS have the preventive effect of face and neck injuries, and are the most effective safety restraint systems.

• Journal of the Korean Society for Precision Engineering
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• v.18 no.4
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• pp.142-150
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• 2001

Automotive manufactures have taken more interests in tailored sheet metals for improving the rigidity, weight reduction, crash durability, and cost savings so that their application to auto-bodies has been increased. However, since the tailored sheet metals do not behave like un-welded sheet metals in press forming operations, the stamping engineers no longer rely only on conventional forming techniques. Futhermore, there is no clear understanding of the characteristics of welded metal which influence the overall press formability of tailored sheet metals. Recently, the computer simulations are prevailing for the evaluation of the formability. Unfortunately, the mechanical property of tailored sheet metal has to be quantitatively defined in the simulation. In this study, the analytical equations are formulated in order to find the mechanical properties of the welded metal in the tailored sheet metal welded by co$_2$laser. Based on force distribution assumption, the constitutive behavior of the welded metal is investigated using uniaxial tensile test results of base metals and tailored sheet metal. Then, the strength coefficient, work-hardening exponent, and plastic strain ratio of laser-welded metal are calculate from those of base metals and tailored sheet metal. In addition, the existence of weld defects in the welded metal is indirectly detected by examining the slop of strength coefficient of the welded metal.

• Journal of Korean Society of Transportation
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• v.32 no.2
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• pp.170-178
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• 2014

Until now, several research on the relationship of traffic crash occurrences and geometric had been conducted and revealed that projects of road alignment, geometric improvement and hazardous segment selection reduced the number of accidents and accident severities. However, such variables did not consider the non-homogeneous characteristics of roadway segments due to the difficulty of data collection, which results in under-estimation of the standard error affecting the overall modeling goodness-of-fit. This study highlights the importance of non-homogeneity by looking at the effect of the non-homogeneous geometric variables through the modeling process. The model delivers meaningful results when using some geometric variables without relevant geometrics' variables.

• Journal of Welding and Joining
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• v.33 no.6
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• pp.27-35
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• 2015

Laser welding sector in the automotive industry has been widely recognized as one of the most important bonding processes, such as parts welding. Efforts to improve productivity and weld quality have been progressing steadily. In addition, laser welding is suitable for welding process that can produce high-quality welds suitable for flexible production and small quantity batch productions. In order to ensure the rigidity of the material, high strength material are applied to more than 1 GPa class body parts and automotive bumper beams. However, not only the situation is that the trend of domestic research, but also development is based on product molding considering freedom of shape where reinforcement is applied to meet the safety regulations and high-speed crash performance, despite the use of high strength materials. The tendency for heat-affected zone (HAZ) softening phenomenon common in areas of laser welded high tensile steel welding confirmed the occurrence of weld softening effect according to the process parameters. Based on this, range of process parameters could be selected for ensuring weld quality.

• Journal of Korean Society of Transportation
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• v.31 no.4
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• pp.58-66
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• 2013

Due to the characteristics of urban freeways such as heavy traffic and high speed, work zone on urban freeways causes the increase of not only the likelihood of crash occurrence but also traffic congestion caused by lane drop, lane change, acceleration/deceleration, and etc. This paper aims to determine the proper length of transition area that satisfies two criteria, mobility and safety, to make the operation of work zone more efficient. For the analysis, three different scenarios were developed by the number of lanes and the proper length of transition area were determined by changing the length from 100m to 500m in 100m increments. The results showed that the proper length of transition area for 3- and 4-lane freeways is 300m, whereas the proper length of 2-lane freeways is 200m. The results indicated that the different length of transition area based on the number of lanes is more desirable and efficient.

• Journal of the Computational Structural Engineering Institute of Korea
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• v.27 no.5
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• pp.379-384
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• 2014

This article describes the dynamic behaviors of a rubber tired gantry crane(RTGC) under typical load conditions which are used in the design of gantry cranes. In order to investigate the dynamic characteristics of an RTGC, we developed a finite element crane model for its huge structure. The finite element model was validated with the modal test results, e.g., natural frequencies and normal modes. And other components of RTGC were converted into detailed 3D CAD models and finally transformed to rigid body models in a dynamic simulation program ADAMS. The load conditions considered in this paper were a normal operating condition(OP1) and container hanging condition with no external loads. As a result, we could find there was large influence of crane's vibration owing to its structural stiffness and deformation. And the vibration of crane could made the movements of RTGC, which occurs crash or malfunction of crane works.

• The Journal of Pediatrics of Korean Medicine
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• v.26 no.2
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• pp.35-46
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• 2012

Objectives The purpose of this study was to find out the characteristics of children patients who had been treated in the Oriental Medical Hospital due to traffic accidents. Methods The study was carried out with 121 children patients who visited the Oriental Medical Hospital from April 2011 to March 2012 and was analyzed by reviewing the patients' charts. Results In the distribution of sex the ratio between boys and girls were similar, but regarding the age, 0~6 year-old group was more than that of 7~15 year-old group. In the traffic accident patterns, 87.6% of the entire children patients were injured by car crash. The highest type in the collision between cars was rear-ending impact. The most patients (48.8%) visited our hospital for oriental medical treatment in less than 3 days after the traffic accident. The number of the first visitors in the Oriental Medical Hospital were 77 (63.6%) and those who visited other western hospitals before and were 44 (36.4%). The most frequent duration of admission and treatment in OPD was less than 7 days. Sleeping disorders (37.1%) were diagnosed the highest in 0~6 year-old group and C-spine sprain (49.0%) was diagnosed the highest at 0~7 years-old group. Herb medications were prescribed to relieve anxiety for 0~6 year-old group and for 7~15 year-old group, those were prescribed to activate blood eliminating phlegm and to normalize Qi flow. The highest effective treatment period was less than 7 days. Conclusions This data suggested that the oriental medical care could be more effective in treating children victims of traffic accidents by confirming many different symptoms depending on the age.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.15 no.2
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• pp.114-123
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• 2005

We analyzed the demographic and job features of 197 shipyard workers with work-related musculoskeletal disorders(WMSDs) compensated by the Industrial Accident Compensation Insurance Act, and the features of the disorders, the causes of operation and the induced behaviors. The three shipbuilding companies surveyed were located in Busan Metropolitan city and Gyungsangnam-do. The results were as follows. 1. The ages of WMSDs patients in shipyard were $43.6{\pm}8.6$ and the job tenure was $14.3{\pm}5.6$. The 40's of them was 40.1%, and the 30's was 29.4%. Patients less than 5 year-work duration were 85.3%, and ones more than 16 year-work duration 6.6%. In occupations, welders were 32.5%, pre-welders 17.3%, and setting engineers 6.6%. 2. The causes of WMSDs in shipyard were works(95.4%) and outer crash or accident shock (3.6%). Based on the standard of the NIOSH induced behaviors, the causes were awkward posture (62.9%), excessive movement(19.3%) and repetitive movement(13.7%). 3. The compensated WMSDs by body part was the highest, 36%, in the spines, 32.0% in both the upper limbs and the spines, and 14% in the upper limbs. The number of cases of WMSDs in body were 96 in the cervical, 79 in the lumbar and 72 in the shoulders. 4. As a result of chi-square test(${\chi}^2$) between diagnosis and operation in body, welding and spot welding had the most diagnoses in all parts of the body among other occupations. Chi-square test(${\chi}^2$) between diagnosis and induced behavior in body showed that awkward postures recorded the highest rate and repetitive movements was the second. 5. The most hazardous occupation was the welding(incidence rate=9.7) and the most hazardous behavior was the awkward posture.

• Journal of Korean Society of Transportation
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• v.35 no.4
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• pp.278-291
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• 2017

Effective installation and operations of traffic safety signs in the advance warning area is of considerable interest for safer traffic management at freeway work zones. This study evaluated the feasibility of traffic safety sign installation based on a driving simulation experiment to take drivers' responsive characteristics into consideration. Both the compliance rate for speed limit and a lane-changing safety index were used for evaluating a set of driving simulation scenarios. It was identified that providing speed limit signs to reduce speed in advance and afterward guiding lane-changing could lead to safer maneuvering of vehicles entering work zones. The outcomes of this study are expected to be useful for revising freeway work zone management policies toward crash prevention.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.33 no.3
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• pp.1105-1113
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• 2013

Understanding the characteristics of truck-involved crashes is of keen interest because such crashes are highly associated with greater potential leading to severer injury. The purpose of this study is to identify factors affecting injury severity of truck-involved crashes on freeways. In addition, a binary logistic regression technique is applied to identify causal factors affecting truck crash severity under normal and adverse weather conditions. Major findings from the analyses are discussed with truck operations strategies including speed enforcement, variable speed limit, and truck lane restriction, from the safety enhancement point of view. The results of this study would be useful for developing traffic control and operations strategies to reduce truck-involved crashes and injury severity in practice.