• 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.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.

• Journal of Korean Society of Occupational and Environmental Hygiene
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• v.33 no.2
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• pp.145-155
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• 2023

Objectives: A fit test panel is needed to identify the fit performance of a respirator and its face seal. This is a criterion for selecting subjects that can represent the facial characteristics of users. Although anthropometry data has been developed for people in United States and China it is not yet present in Korea. This study aimed to develop a Korean fit test panel and test headform. Methods: For the 7th and 8th waves of the Size Korea anthropometry data, facial measurements of 11,429 people aged 15 to 69 years were used for analysis. PCA and bivariate panel were classified using the ISO16976-2:2022(E) anthropometrics analysis method. Based on this result, a static headform was developemed and a fit test chamber was constructed. Results: Of the 11,429 Korean people used for principal component analysis, 11,300 were included in the ellipse, marking an acceptance rate of 98.87% on PCA panel. The face types were classified into five types. Among them, a large, medium, and small static headform were printed using a 3D printer. In addition, 10,985 people (96.12%) were included in the bivariate panel based on face length and face width. The y-axis (face length) boundary was 97.87 to 134.59 mm, and the x-axis (face width) boundary was 120.75 to 158.23 mm. Conclusions: Compared to the ISO analysis, the Korean principal component was narrower in the width item (PC1) and longer in the length item (PC2). For the future, it is necessary to conduct a fit test using the developed headform and chamber device to confirm the usefulness of this Korean test panel. Therefore, this study is considered valuable as basic research for Korean test panels.

• 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.

• 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.

• 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.

• 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.

• Fashion & Textile Research Journal
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• v.25 no.2
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• pp.248-254
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• 2023

This study aims to measure the skin rigidity of different facial areas among Koreans and propose guidelines for each area's skin rigidity that can be applied with a facial robot for testing respiratory protective devices. The facial skin rigidity of 40 participants, which included 20 men and 20 women, aged 20 to 50, was analyzed. The rigidity measurement was conducted in 13 facial areas, including six areas in contact with the mask and seven non-contact areas, by referring to the facial measurement guidelines of Size Korea. The facial rigidity was measured using the Durometer RX-1600-OO while in a supine position. The measurement procedure involved contacting the durometer vertically with the reference point, repeating the measurement of the same area five times, and using the average of three values whose variability was between 0.4 and 4.2 Shore OO. The rigidity data analysis used precision analysis, descriptive statistics analysis, and mixed-effect ANOVA. The analysis confirmed the rigidity of the 13 measurement areas, with the highest rigidity of the face being at the nose and forehead points, with values of 51.2 and 50.8, respectively, and the lowest rigidity being at the chin and center of the cheek points, with values of 19.2 and 20.7, respectively. Significant differences between gender groups were observed in four areas: the tip of the nose, the point below the chin, the area below the lower jaw, and the inner concha.

• Journal of the korean academy of Pediatric Dentistry
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• v.26 no.1
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• pp.185-199
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• 1999

The purpose of the present study was to investigate craniofacial patterns in Korean male and female adults, and to compare morphologic differences between different facial types. In order to get configurational groupings, standardized lateral and P-A cephalograms of 174 Korean adults were measured and analyzed with seven angular, nineteen linear, four ratio, and two index measurements. Ward's minimum variance cluster analysis was employed to divide the sample into groups having similar craniofacial morphology, and thereafter, inductive statistics(t-test) was used to characterize morphologic differences of the divided groups. And also, Pearson correlation coefficients were calculated to assess correlation between the cranial dimensions and upper/lower anterior facial height(UAFH, LAFH) in each facial types for both male and female The results were as follows; 1. There existed sexual dimorphism in most of variables except SN-FH angle, palatal plane angle, facial axis angle, facial index, lower anterior facial height ratio and upper facial height ratio. 2. A brachycephalic headform ($0.84{\pm}0.05$) with leptoprosopic facial form ($0.92{\pm}0.05$) was appeared in male, and a mesocephalic headform ($0.86{\pm}0.06$) with leptoprosopic facial form ($0.92{\pm}0.04$) was exhibited in female. 3. Facial types in both male and female subjects were divided into two groups, Group A (mesoprosopic facial type) and Group B (leptoprosopic facial type). The morphologic differences between Group A and Group B were as follows: a. Cranial measurements including index, angular and linear measurements were not found to be different between Group A and Group B in both sexes. b. Increased UAFH, LAFH, and upper/lower anterior dental heights were exhibited in Group Bs of both male and female. c. In both male and female, ramus height and mandible length showed no difference between Group A and Group B. However, genial angle was found to be larger in Group B than Group A. Therefore, the morphologic differences between two groups in male and female were closely related to less favorable anatomic morphology of the mandible. 4. LAFH and UAFH showed no relationships with cranial dimensions in male and female.