• Title/Summary/Keyword: Helmets

Search Result 95, Processing Time 0.027 seconds

Finite Element Analysis on the Stress and Deformation Behaviors of a Safety Helmet (안전헬멧의 응력 및 변형거동에 관한 유한요소해석)

  • Kim, Chung-Kyun
    • Journal of the Korean Institute of Gas
    • /
    • v.13 no.4
    • /
    • pp.27-32
    • /
    • 2009
  • This paper presents the stress and deformation behaviors using the finite element method as a function of the thickness of the helmets without the bead frames on the top of the shell structure. The helmet that would provide head and neck protections without causing discomfort to the user when it was worn for long periods of time should be manufactured for increasing the safety and impact energy absorption. The FEM computed results show that when the impulsive force is applied on the top surface of a helmet, the maximum stress and strain have been occurred around the position of an applied impact force, which may lead to the initial failure on the top surface of the helmet shell. As the helmet thickness is decreased from 4mm to 2mm, the impact energy absorbing rate is radically increased, and the maximum stress of the helmet is increased over the tensile strength, 54.3MPa of the thermoplastic material. Thus, the top surface of the helmet should be supported by a bead frame and increased thickness of the shell structure.

  • PDF

A Study of Official Hats Shown on Shaman's Costumes of Seoul Village Gut (서울 마을굿 무속복식에 나타난 관모 연구)

  • Kim, Eun-jung;Yim, Lynn
    • Fashion & Textile Research Journal
    • /
    • v.17 no.3
    • /
    • pp.364-371
    • /
    • 2015
  • This study investigated and analyzed Sadanggut for General Namyi, Agisee Gutdang in Haengdang-dong, Dodanggut in Bonghwa Mountainto examine the type and characteristics of official hats for shaman's costumes based on Seoul village gutas a spiritualistic shaman revealing the divinity of music for gutthrough singing, dancing, divine material and official hats. Commonly worn official hats were Goggal(conical hats), Jeonlip(soldier's felt hats), and Heuklip(black hats) for Seoul village gut as the object of thisstudy. Each official hat had a close relationship with subjects for divinity and musical meaning for gut. Julip(Red hats), Jokduri(bride's headpiece), helmets, Iksubgwan(King's official hat), and Daesu(Queen's a big wig with various hairpins) were also worn. Official hats worn for Seoul village gutwere understood to symbolize divinity and raise authority and dignity to the public through aggressive appearance, exaggeration and splendor. Concretely, official hats at Seoul village gut first had roles to materialize the divinity of each music of gut. Second, recognized as a part of performance or traditional culture in present day, aggressive official hats were favored to supply splendid attraction and maximize scenes of divined heroic epic poem in gut. Third, for Seoul village gut, colors and silhouettes of modern traditional costumes were reflected pursuing partial change and focused on exaggeration and splendor to express the mirth and festival of gutwhile maintaining traditional costumes.

Effects of Hair Style on Human Physiological Response in a Thermal Neutral Environment (쾌적 환경에서 헤어스타일 유형이 인체 생리 반응에 미치는 영향)

  • Kim, Myung-Ju
    • The Korean Journal of Community Living Science
    • /
    • v.21 no.1
    • /
    • pp.117-124
    • /
    • 2010
  • Recently, research on variables associated with hair styles are increasing with the spreading of total coordinated intention in the fields of clothing and cosmetology. In the present study, we focused on examining the skin temperature on the scalp(the vertex, temporal, and occiput), humidity on the occiput, skin temperatures (the forehead, back of ear, back of neck, upper back, abdomen, forearm, hand, thigh, calf, and foot), rectal temperature, total body mass loss by hair styles in a thermal neutral environment. Four young females participated as subjects. For a certain period, each subject had the five different hair styles in a random order: (1)Straight short hair(SS), (2)Perm waved short hair(PS), (3) Straight long hair(SL), (4)Perm waved long hair(PL), (5)Ponytail style(PT). Subjects wore briefs, bra, shirts with long sleeves, long legged training pants, and socks. The environmental variables of a climatic chamber were kept constant at $21{\pm}0.5^{\circ}C$ of air temperature and 55${\pm}$5%RH of air humidity. The results indicated the following: The skin temperature and humidity on the scalp did not show any significant differences among five different hair styles, but straight long hair style(SL)was the highest on the vertex, temporal, and occiput. The temporal skin temperature($29.8\sim30.8^{\circ}C$) was the highest, while the vertex skin temperature($28.7\sim30.1^{\circ}C$) was the lowest. Humidity on the occiput was the highest in the perm waved long hair style(PL). The back of ear skin temperature was significantly lower in the ponytail style(PT) than in the other four hair styles(p<.001). In the straight long hair style(SL), the skin temperature on the back of the neck and on the upper back were significantly higher than those of the other four hair styles(p<.01). Mean skin temperature and rectal temperature had no significant differences among hair styles. Total body mass was the highest in the perm waved long hair style(PL)(p<.05). We acquired fundamental data to enable the improvement of the current hair clinic system, wigs, functional hats, and helmets.

The Study of Field Survey for the Analysis of Occupational Accident Causes in Korean Construction Industry (건설산업재해 원인분석 조사연구)

  • 이영섭
    • Journal of the Korean Society of Safety
    • /
    • v.1 no.1
    • /
    • pp.51-59
    • /
    • 1986
  • This study was conducted to analyse the exact causes of occupational accidents in Korean construction industry and to contribute to the accident prevention programs. The results and conclusions of the field survey are as follows : 1) The accidents caused by hazardous conditions are 96 percent, and those by unsafe acts are 97.3 percent. The accidents caused simultaneously by two categories are nore than 96 percent. 2) The injured workers who were employed less than 3 months are 71.1 percent. Safety training for newly recruited workers should be required. 3) More than 40 percent of all accidents were occurred in the morning and more than 30 percent were in summer. Required caution should be paid for the time and season. 4) Fracture, cut/laceration/puncture and multiple injuries in the lower extremeties, upper entremeties and head as well as many kinds of injuries by the fall from elevation mainly occurred. Safety. shoes, safety gloves, safety helmets, safety glasses, face shields and safity belts should be used 5) As the sources of injuries, each of building/structure and materials is one third of all sources, and machinery is a quarter. 6) The use of hazardous methods/procedures, defects of agencies and inadequate guarding of builing/structure, materials' and machinery mainly caused the accident types, such as s truck by, struck against, fall from elevation, and fall on same level. Such a hazardous conditiion should not be used and be correctet 7) The unsafe acts, such as improper use of hands or body parts, the operation or working at unsafe speed and improper use of equipment mainly caused accidents. Safety training for the control of such a unsafe acts should be strengthened.

  • PDF

An Analysis of the Cotton Fabric armour(綿甲) in the late Joseon Korea - with Emphasis on the Remaining Artifact in the National Museum of Korea - (조선 후기 면갑(綿甲) 유물 분석 - 국립중앙박물관 소장 유물을 중심으로 -)

  • Park, Ga Young;Song, Mi Kyung
    • Journal of the Korean Society of Costume
    • /
    • v.63 no.4
    • /
    • pp.158-167
    • /
    • 2013
  • The cotton fabric armour for lower class soldiers can be found from the historical records of the mid-Joseon Korea. And the records show that the form and the structure of the armour was modified in the late 19th century in order to provide better protection from gunshots for the soldiers in the midst of the invasions from the West. This is a survey and research of the only artifact of the cotton fabric armour remaining in Korea - for its form, dimensions, and design. Using the historical records as reference, we can confirm the structure and characteristics of the cotton fabric armour of the Joseon period. This cotton fabric armour, preserved in National Museum of Korea, is a vest-type armour made of 30 layers of cotton. On the right shoulder, there is a button for tying knots and strings were tied under both armpits. On the surface of the cotton fabric armour there were some characters and patterns stamped in black. Presently, this artifact in Korea is the only specimen relic of its sort, but there are some other related relics in foreign countries including helmets and belts. Continuous researches would help extend the scope of armour study beyond the traditional researches that only focuses on the armours of the officials, thus helping us to understand the military costumes in traditional Korea.

A Study on the Costume of Bactria, center of Silk Road - Focusing Analysis of Antiquities - (실크로드의 중심 박트리아의 복식 연구 - 유물 분석을 중심으로 -)

  • Chang, Youngsoo
    • Fashion & Textile Research Journal
    • /
    • v.19 no.4
    • /
    • pp.400-410
    • /
    • 2017
  • Bactria was the intersection of transportation between Greece-Iran and Central Asia at the Silk Road. This kingdom was Greek in all of its ruling classes. Because the Greek culture of Bactria spread to India and the east, Bactria was a very important place in ancient civilizations. The purpose of this study is to understand the life and the various cultures of Bactria and the influence of Greek culture on the costumes of Bactria. The research method was approached through the analysis of the empirical data. Data on antiquities were analyzed in European exhibition catalogs and secondary data collected from Internet. The results of this study are as follows: First, the original costume of Bactria was identified in two styles in the reliefs of the Persian Achaemenid. One is the tunic jacket sarapis that goes down to the knee and wide trousers with half-length boots. The other is the Scythian style trousers that looks like a barrel in a Sarapis. Second, in the Bactrian coin depicting the bust of the Bactrians, the hair styles and headgear of the Bactrian kings were analyzed. The Bactrians wore braids with short curly hair and wore Macedonian hats and helmets on them. Third, the relics excavated from the ruins of Ai-Khanuom depicted the forms of the ruling classes of Bactria. The dress styles and hair styles of gods and priests were imitating the form of the Greek costume as it is.

Numerical Simulation of Steel/Kevlar Hybrid Composite Helmet Subjected to Ballistic Impact (탄도 충격을 받는 Steel/Kevlar 혼합복합재 헬멧 수치 시뮬레이션)

  • Jo, Jong Hyun;Lee, Young Shin;Jin, Hai Lan
    • Transactions of the Korean Society of Mechanical Engineers A
    • /
    • v.36 no.12
    • /
    • pp.1569-1575
    • /
    • 2012
  • In this study, ballistic impact effects on a helmet were investigated using the AUTODYN-3D program. Two types of materials were used for manufacturing the helmet: single Kevlar and Steel/Kevlar hybrid composites. Furthermore, two types of bullets were used in the simulation: steel spherical and 7.62 mm full-jacketed. In the simulation, the shape deformation of the projectile and internal energy were calculated. From the results, impact velocities above 655 m/s and 845 m/s were required to perforate the Steel/Kevlar helmet with steel spherical and 7.62 mm full-jacketed bullets, respectively. The results show that there was a large difference between the ballistic resistance of the Kevlar and Steel/Kevlar helmets. For the simulation on an NIJ-STD-0106.01 Type II helmet, a 7.62 mm fulljacketed bullet with a striking velocity of 358 m/s was used. Simulation results show that the Steel/Kevlar helmet could resist a 7.62 mm full-jacketed bullet traveling at 358 m/s.

A Study on Cheollik, the Military Officials' Clothes, in the Joseon Dynasty (조선시대무관(朝鮮時代武官)의 철릭[帖裏] 연구)

  • Keum, Jong-Suk
    • The Research Journal of the Costume Culture
    • /
    • v.18 no.5
    • /
    • pp.960-976
    • /
    • 2010
  • Even though Joseon Dynasty strictly identified between military and civil officials, the dress and its ornament have been studied only based on embroidery emblems that are correctly identified between military and civil officials. Thus, this study intends to research the features of the only military officials uniform, Cheollik, different from the civil officials's identifying them with other features shown from the records, unearthed relics, stone statue, Joseon-tongsinsa-haengnyeoldo(Illustration of Joseon Delegation to Japan), etc., and its results are as follows: First, for wearing examples of the military officials, from the facts that they had worn mainly ordinary clothes, etc. on announcement of military service examination. There was no difference between military and civil officials's clothes by Daejeonhusokrok and the other documents, and there was an assertion that the form of the military and civil officials's clothes should be different by the document, Hongjejeonseo, in the latter term of the Joseon Dynasty. It is presumed that length, width and shape of sleeves might have been different. Second, unearthed Cheollik of the military officials are mostly from the 16th~17th centuries and most of them have removable sleeves according to statistics. The skirt had an opening and one or two slits. Various textiles were used. Third, military official statues of high governor wear small caps and helmets. They wear Cheollik with the collars same as the collar of Bangryeong and Jikryeong, which is also called Dopji Cheollik. It would be considered as they wear the Bangryeong on top of the Cheollik. Fourth, militarly officials described on the Joseon-tongsinsa-haengnyeoldo(Illustration of Joseon Delegation to Japan) wear Cheollik, Rip, Donggae, Okro, Hongsadae, Hwando, Deungchae.

The Distribution Condition and Clothing Construction Factors of the Working Clothes - Reference to the Changwon National Industrial Complex -

  • Park, Gin-Ah;Park, Hye-Won
    • Journal of Fashion Business
    • /
    • v.12 no.3
    • /
    • pp.116-135
    • /
    • 2008
  • To investigate the actual distribution condition and clothing construction factors of the working clothes supplied to the Changwon national industrial complex, 5 major companies in machinery, automotive, industrial engineering, shipbuilding and rolling stock in the industrial complex located in Gyeongsangnam-Do were selected. The questionnaire designed for the research consisted of working clothes distribution policies in manufacturing industry and the actual conditions of the design facts, repair and maintenance of the working clothes, etc. The analysis of the clothing construction factors of the working clothes provided by 5 respondent companies were conducted in parallel. The results derived from the study were as follows: The basic types of working clothes were the blouson jacket and straight pants; safety equipments for manufacture were safety helmets, gloves, snickers, goggles, masks, ear caps, wristlets, leggings, apron, etc. The size-charts adopted by the participant companies were the small-medium-large and cm/inch measurement size systems. To solve wearer's dissatisfaction with the garment fit, certain clothing construction factors were used, e.g. strap bands and the elastic band on a waist band. The types of fabrics used for the working clothes were mainly polyester/cotton and polyester/rayon blended ones. Moreover, to provide with more air permeability to wearers, the warp knit material was used to construct the lining and the armpit or back bodice slits. Lock, two-thread chain, safety, overedge stitches were applied with flat, lap felled, French, superimposed, lapped, bound and edge finishing seams to construct the working clothes selected.

Modeling Technology on Free-form Surface of a New Military Personal Head using Quick Surface Method (퀵서피스기법을 이용한 신장병 두상의 자유곡면 모델링 기술)

  • Lee, Yong-Moon;Hwang, Tae-Son;Kim, Hun;Nam, Hee-Tae;Lee, Kee-Hwan;Kang, Myungchang
    • Journal of the Korean Society of Manufacturing Process Engineers
    • /
    • v.17 no.6
    • /
    • pp.170-176
    • /
    • 2018
  • Recently, weapon system requires personal protection products due to the explosion of rapid-fire explosion, which is considered to be multi threat in modernization, complication and war against terrorism. However, the conventional Korean military bullet protection helmets are not suitable for wearing convenience and combatant interoperability in terms of ergonomic. In this paper, we propose a suitable 3D Scanning method for the head, and compare the measured 3D dimension with the existing 2D measurement value to identity the reliability. Reverse engineered soldier head using the quick surface method was realized with a perfect free-form surface and satisfactory tolerance range (${\pm}0.2mm$). Through the comparison of 3D and 2D measured head dimensions, the absolute error value was 0.73 mm on average and relative error was 0.35 %, confirming the high accuracy of the 3D scan modeling. Also, quick surface method using 3D scanner is suggested a fast and accurate skill for ergonomics in obtaining the head modeling needed for military's personal bullet protection helmet design.