• Title/Summary/Keyword: Impact protection

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Analysis of Tidal Stream around Ship Impact Protection of Incheon Bridge Using CFD (CFD를 사용한 인천대교 충돌방지공 주변의 조류 흐름장 해석)

  • Kim, Gunwoo;Oh, Sang Ho;Yi, Jin-Hak;Kwon, Ohjung
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.11a
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    • pp.169.2-169.2
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    • 2010
  • Recently, the massive offshore bridges in a ship passage have been constructed on the sea. Therefore, the ship impact protection for the bridge-piers are installed to consider the possibility of vessel collision danger. Due to the ship impact protection, the flow-field characteristics are changed in comparison with the condition without the ship impact protection. Especially, the fluid velocity between the pier and the ship impact protection is possible to increase due to the contraction of the cross sectional area of flow. In this study, the tidal energy magnitude around the ship impact protection of Incheon bridge is assessed by simulating the flow-field by using FLOW-3D software.

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Development and Evaluation of Fall Impact Protection Pad (낙상충격 보호패드의 개발 및 평가)

  • Park, Jung Hyun;Lee, Jin Suk;Lee, Jeong Ran
    • Fashion & Textile Research Journal
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    • v.20 no.4
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    • pp.422-428
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    • 2018
  • In this study, we developed honeycomb pads using foam and polymer gel and verified the impact protection performance of pads for the development of a fall protection pants for elderly women aged 65 and over who have a high risk of fracture due to falls. The results are as follows; In the first experiment, the impact protection performance was evaluated for four honeycomb pad samples (CR foam, EPDM foam, hardness 15 polymer gel, and hardness 30 polymer gel) manufactured to a thickness of 5 mm using a single material. When the force of about 10757N was applied to the specimens, all four pads reduced the impact force to 3100N or less. Polymer gels showed better protection than foam materials. In the second experiment, the thickness of the protective pad was set to 8 mm in order to improve the shock absorbing performance of the protective pad. As a result of evaluating the impact protection performance of the foam single pad and foam gel composite pad, the impact absorbing performance of the foam single pad was better. Finally, four kinds of protection pads were made by assigning the foam single pad and the foam gel composite pad to pants type and underwear type respectively. The pad thickness of the main protection area was set to 8 mm to enhance the protection, and gradually decreased to 5mm and 3mm toward the edge to improve the appearance and fit.

Design of Fall Impact Protection Pads Using 3D Printing Technology and Comparison of Characteristics according to Structure (3D 프린팅 기술을 활용한 낙상충격 보호패드 설계 및 구조에 따른 특성비교)

  • Park, Jung Hyun;Jung, Hee-Kyeong;Lee, Jeong Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.42 no.4
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    • pp.612-625
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    • 2018
  • This study designed 16 kinds of basic structure and 4 kinds of modified structure for impact protection pads with a spacer fabric shape. The pad is a structure in which hexagonal three-dimensional units, composed of a surface layer and a spacer layer, are interconnected. Designed pads were printed with flexible $NinjaFlex^{(R)}$ materials using a FDM 3D printer. The printed pads were evaluated for impact protection performance, compression properties and sensory properties. The evaluation of the impact protection performance indicated that basic structures better than CR foam material at 20cm height were DV1.5, DX1.5, DX1.0, DV1.0 and HV1.5. The evaluation of the compression properties for the five types, with good results in the impact protection performance, indicated that DV1.0, DX1.0, DV1.5, HV1.5 and DX1.5 showed good results, respectively. The sensory evaluation of DV1.0, DX1.0, and DV1.5, which with good results when considering both the impact protection performance and the compression performance, showed that DV1.0 were the best for surface, flexibility, compression and weight. Therefore, DV1.0 is shown to be the best structure for protection pads.

Structure Design of Fall Impact Protection Pad Using 3D Printing Technology and Comparison of Characteristics According to Filament Material (3D 프린팅 기술을 활용한 낙상충격 보호패드 구조설계 및 필라멘트 소재에 따른 특성 비교)

  • Park, Jung Hyun;Jung, Hee-Kyeong;Lee, Jeong Ran
    • Journal of the Korean Society of Clothing and Textiles
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    • v.41 no.5
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    • pp.939-949
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    • 2017
  • This study uses 3D printing technology to design and fabricate a fall impact protection pad with a spacer fabric structure. The design of the pads consists of hexagonal three-dimensional units connected in a honey-comb shape; in addition, the unit consists of a surface layer and a spacer layer. Protect pads were designed as either a hexagonal type or diamond type according to the surface layer structure; subsequently, a spacer filament was also designed as the most basic I-shape type. Designed pads were printed using four types of flexible filaments to select suitable material for a fall impact protection pad. Impact protection performance and bending stiffness were evaluated for the eight type of pad outputs. As a result of the impact protection performance evaluation, when the force of 6,500N was applied, the force passed through the pad was in the range of 1,370-2,132N. FlexSolid$^{(R)}$ and Skinflex$^{TM}$ showed good protection performance and cubicon flexible filament showed the lowest protection. NinjaFlex$^{(R)}$ was found to be the most flexible in the bending stiffness evaluation.

A Study on the Injury Criteria of the Occupant Protection Performance of Crush Cushions (충격흡수시설의 탑승자보호 성능평가 기준에 관한 연구)

  • Lim, Jae-Moon;Jung, Geun-Seup
    • Transactions of the Korean Society of Automotive Engineers
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    • v.16 no.2
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    • pp.49-57
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    • 2008
  • The performance of crash cushion systems is certified through the full scale crash tests by the standard for installation and maintenance guidelines for roadside safety appurtenance. The impact severities of impacting vehicles in collision with crash cushion systems are rated by indices THIV and PHD. Crash test results are considered to study the performance of three crash cushion systems. In case of the frontal impact or the offset frontal impact, the results show that THIV values of three systems are very close to the threshold limit for the occupant protection. Also, the results show that PHD would be improper for the occupant protection performance index. In order to improve the occupant protection performance of crash cushions, ASI needs to be included in the impact severity index.

Design of motion-adaptable 3D printed impact protection pad (동작 가변적 3D 프린팅 충격보호패드의 설계)

  • Park, Junghyun;Lee, Jinsuk;Lee, Jeongran
    • The Research Journal of the Costume Culture
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    • v.30 no.3
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    • pp.403-413
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    • 2022
  • The purpose of this study was to develop a 3D mesh-type impact protection pad with excellent motion adaptability and functionality by applying 3D printing technology. The hexagonal 3D mesh, which constitutes the basic structure of the pad, comprises two types: small and large. The bridge connecting the basic units was designed as the I-type, V-type, IV-type, and VV-type. After evaluating the characteristics of the bridge, it was found that the V-type bridge had the highest flexibility and tensile elongation. The hip joint pad and knee pad were completed by combining the hexagonal 3D mesh structure with the optimal bridge design. The impact protection pad was printed using a fused deposition modeling-type 3D printer with a filament made of thermoplastic polyurethane material, and the protection pad's performance was evaluated. When an impact force of approximately 6,500N was applied to the pad, the force attenuation percentage was 78%, and when an impact force of approximately 8,000N was applied, the force attenuation percentage was 75%. Through these results, it was confirmed that the 3D-printed impact protection pad with a hexagonal 3D mesh structure connected by a V-shaped bridge developed in this study can adapt to changes in the body surface according to movement and provides excellent impact protection performance.

A Research on Institution's Countermeasure for Personal Information Protection Act Based on the Examples of Performing the Privacy Impact Assessment (개인정보 영향평가 수행 사례에 기반한 기관의 개인정보보호법 대응방안에 관한 연구)

  • Cho, Sung Kyu;Jun, Moon Seog
    • Journal of Korea Society of Digital Industry and Information Management
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    • v.8 no.1
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    • pp.89-98
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    • 2012
  • According to the enforcement of Personal Information Protection Act as of September 2011, the laws and regulations for the protection of personal information that were applied only to the certain sectors such as information & communication network, financial institutions, public sector etc. for the time being has been expanded to apply to all public and private sectors to process personal information. In particular, because the public institutions are obliged to be mandatorily conducted of the Privacy Impact Assessment, it will be enforced in earnest for each agency's informationization business that handles personal information. In this paper, I examine the most derived vulnerability and set up the improvement measure to supplement it with the examples of 10 of all the institutions conducting the Privacy Impact Assessment in the year 2011. And, I suggest the measures to be prepared by the institutions to observe the Personal Information Protection Act.

Study on a Standardized Rockfall-Protection Fence for Various Rockfall Impact Energy using Finite Element Analysis (유한요소해석을 이용한 다양한 낙석 충돌에너지에 대한 표준 낙석방지울타리 형식 제시 연구)

  • Park, Hyungon;Jang, Hyunick;Kim, Bumjoo;Moon, Jiho
    • Journal of the Computational Structural Engineering Institute of Korea
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    • v.33 no.5
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    • pp.297-302
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    • 2020
  • Korea has many mountainous regions, and slope collapse that can lead to damage in road facilities and loss of lives often occurs. Rockfall-protection facilities are necessary to reduce such damages. Among these facilities, the standard Korean rockfall-protection fence is designed to resist 50 kJ of rockfall impact energy. However, the range of rockfall energy significantly varies depending on the condition of the slope, and it sometimes reaches up to 100 kJ. Thus, providing several types of standardized rockfall-protection fence is necessary to address the different rockfall impact energy for efficient response to rockfalls. This paper presents a study on standardized rockfall-protection fence for various rockfall impact energy using finite-element analysis. According to the results, standardized rockfall-protection fences against rockfall impact energy of 30 and 100 kJ were proposed and have been verified.

Evaluation of Physical Properties of Material Combination for Fabricating Protection Pads for Women's Army Combat Uniforms (여군 전투복 내 관절 부위 보호 패드 개발을 위한 설계 변인 조합에 따른 물성 평가)

  • Okkyung Lee;Heeran Lee;Soyoung Kim;Yejin Lee
    • Journal of the Korean Society of Clothing and Textiles
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    • v.47 no.2
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    • pp.311-322
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    • 2023
  • In this study, the properties of various material combinations were evaluated and an ideal material for fabricating protection pads for women's army combat uniforms was determined. Eight specimens were used for the evaluation: two types of materials, namely thermoplastic polyurethane for 3D printing, T and ethylene-vinyl acetate, E; two infill densities, namely 10%, 10 and 30%, 30; two types of pad designs, i.e., without holes, A and with holes, B; 2×2×2=8 and control E. The tensile strength, flexural strength, impact absorption, and weight of these specimens were evaluated. Results revealed that E was the most flexible material; however, its tensile strength and impact absorption were very low. Protection pads made from T (T-10A, T-10B, T-30A, and T-30B) had excellent tensile strength and impact absorption; however, they had low performance in ease of movement. Alternatively, protection pad with holes and an infill density of 30% produced using a combination of T and E had a high initial tensile modulus and exhibited excellent impact absorption. Moreover, it was flexible and light, which satisfies the standards and conditions required by protection pads. However, if T-E-10A and T-E-30B exhibited low impact absorption, as required, they can be regarded as appropriate materials for protection pads.

Aesthetic Value of Korean National Parks' Landscape: Its Appreciation and Protection Strategies (국립공원 경관 가치의 증진방안)

  • Park, Kyeong
    • Journal of Environmental Impact Assessment
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    • v.12 no.5
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    • pp.369-382
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    • 2003
  • Natural resources managers have considered the landscape without detailed consideration of aesthetic values of the landscape and geomorphological significance of unique landforms. Since EIA system was introduced in 1981, values associated with landscape protection have been neglected at best compared with those values traditionally attributed to environmental protection, including clean air, water quality and species protection. Black top highways are being built without consideration of harmful effects to the sea cliffs. Sea walls and tetrapod are being installed to protect the coastal towns and fish markets for tourist. However, beach itself are experiencing accelerated erosion due to the shortage of proper coastal engineering expertise. Hotels and condominiums are under construction on a massive scale around the national parks, which substitute the scenic ridges with concrete profiles. To protect the scenic beauty of national parks, their design and construction material should be more harmonious with the surroundings. Therefore, visual impact assessment should be applied both within the national park boundary and beyond to enhance the aesthetic values of national parks.