• Title/Summary/Keyword: protective structure

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The study on Topology Optimization for Crashworthiness enhancement in Protective shell frame of Rolling Stock leading-cab (철도 차량 전두부 충돌 피해 저감을 위한 Protective shell frame의 위상 최적화에 관한 연구)

  • Kim, Hyun-Jun;Kim, Se-Hoon;Jung, Hyun-Seung;Kwon, Tae-Su;Suh, Myung-Won
    • Proceedings of the KSR Conference
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    • 2007.05a
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    • pp.138-143
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    • 2007
  • The leading-cab (high energy absorption area) of rolling stock directly is impacted on the frontal crash unlike other cabs. Thus, leading-cab has a structurally complex shape to solve getting concentrated loads. However, in order to enhance structural performance and to achieve the weight reduction of cab, changing the sizes and adjusting the distance of members do not take an effective result. Therefore, in design phase, to find the material arrangement which helps structural capacity be better should be done. This research applies the topology optimization to concept design of protective shell frame on strategy of crush energy absorption with considering pressure and vertical loads acting on the principal part of leading-cab. In this research, topology optimization method focuses on structural design, and which yields optimal material arrangement under given loads and boundary conditions using density method which has the density of material as design variables. Finally, this research presents optimal material arrangement and structure of protective shell frame on given loads with applying topology optimization.

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Study on Tribological Behavior of Porous Anodic Aluminum Oxide with respect to Surface Coating (다공성 산화알루미늄의 표면코팅에 따른 트라이볼로지적 특성연구)

  • Kim, Young-Jin;Kim, Hyun-Joon
    • Tribology and Lubricants
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    • v.33 no.6
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    • pp.275-281
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    • 2017
  • In this work, we have fabricated anodic aluminum oxide (AAO) with ordered nanoscale porosity through an anodization process. We deposited gold and nano-organic thin films on the porous AAO surface to protect its structure and reduce friction. We investigated the tribological characteristics of the porous AAO with respect to the protective surface coatings using tribometers. While investigating the frictional characteristics of the samples by applying normal forces of the order of micro-Newton, we observed that AAO without a protective coating exhibits the highest friction coefficient. In the presence of protective surface coatings, the friction coefficient decreases significantly. We applied normal forces of the order of milli-Newton during the tribotests to investigate the wear characteristics of AAO, and observed that AAO without protective surface coatings experiences severe damage due to the brittle nature of the oxide layer. We observed the presence of several pieces of fractured particles in the wear track; these fractured particles lead to an increase in the friction. However, by using surface coatings such as gold thin films and nano-organic thin films, we confirmed that the thin films with nanoscale thickness protect the AAO surface without exhibiting significant wear tracks and maintain a stable friction coefficient for the duration of the tribotests.

A Study on the Change of Physical Capability of Waterproofing Layer after the Application of Static Load and Moving Load to a Non-Exposed Type Waterproofing Layer (비노출 방수층에 작용하는 정하중과 동하중 작용 후의 방수층 물성변화에 관한 연구)

  • Seon, Yun-Suk;Kim, Jin-Seong;Oh, Sang-Keun
    • Proceedings of the Korean Institute of Building Construction Conference
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    • 2007.04a
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    • pp.141-145
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    • 2007
  • The part in the structure that is most affected by changes of external temperature is the protective concrete layer that protects a waterproofing layer. Also, the waterproofing layer that is situated under or on the back of such a protective concrete layer is affected by temperature and the behavior of the protective concrete layer under the condition of consolidation or close adhesion. In particular, in many cases, the damage is serious mainly around the projection (such as a parapet), crack, and joint (expansion joint). However, there is no proper way of examining again the non-exposed waterproofing layer once it has been constructed. Therefore, there is an assessment only on the physical property of materials and the capability of the layer in construction, and there is no actual assessment in consideration of its environmental condition or the condition of the use of buildings after construction. Therefore, in order to create more pleasant buildings and to enhance the durability of structures, this study conducts research into the change of capability of non-exposed waterproofing material after the application of a static load and moving load on the waterproofing layer situated under or on the back of protective concrete.

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Adhesion Characteristic and Porosity Change of Alkali Silicate Impregnant of Concrete (Silicate계 콘크리트 함침제 도포에 따른 부착특성 및 공극변화)

  • Song, Hun;Chu, Yong-Sik;Lee, Jong-Kyu;Lim, Young-Chul
    • Journal of the Korean Ceramic Society
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    • v.47 no.4
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    • pp.276-282
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    • 2010
  • There are the impregnating layer formation by surface protective materials or impregnants and the adhesion method by polymer, FRP sheet or steel plate in the surface protective method of concrete structure. The surface impregnation method by impregnants improves the durability of concrete structure by modifying the structure of the concrete surface and also have a merit that can be shortly applied in place without the decrease of concrete surface appearance and is easily applied again. This study is interested in manufacturing the concrete surface impregnants including lithium and potassium silicate for the repair of the exposed concrete and the color concrete requiring the advanced function in view of the concrete appearance. The durability and porosity properties was tested for the review of application. The result of this study show that the effective content of silicate ranges 5 to 20% and the separate application of the first impregnant and the second impregnant is effective for the optimum performance. The adhesion in tension is slightly increased but the reinforcement of concrete substrate is slight. So, the concrete impregnant of this study is more desirable for the improvement of durability rather than the reinforcement.

A Study on the Radiograph Inspection of Specimen in Welding Pass Using ATOS 80 High-strength Steel (ATOS 80 고장력강의 용접 패스에 따른 용접부 방사선검사에 관한 연구)

  • Baek, Jung-Hwan;Choi, Byung-Ky
    • Journal of the Korean Society of Manufacturing Technology Engineers
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    • v.21 no.6
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    • pp.915-919
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    • 2012
  • In constructing all kinds of equipment and steel structure, parts with discontinuities such as weld defects formed in the welded structure can generate fatigue cracks that results in damage or accidents. In this study, weld zones are investigated with X-rays and the latent images are put on film. Weld zone defects can be verified by developing the film. As weld defects are investigated by radiographic testing and correlated with the welding condition, more appropriate welding conditions can be found. According to the result of X-ray radiographic inspection of butt welding ATOS 80 high-strength steel with a thickness of 12mm, the best conditions for welding without creating weld defects are 4 weld-passes, a protective gas of 20% $CO_2$ and 80% Ar, a protective gas flow of 20L/min, a welding current of 200A, an arc voltage of 24V, a welding speed of 14.4cm/min, a welding rod angle of $50^{\circ}$, a welding gap of 5 mm with a ceramic base, and sand pre-heating to $160^{\circ}$ Celsius prior to welding.

A Study on Crashworthiness for the Front Structure of TGV (고속전철 TGV-K 전두부의 충돌안전도에 관한 연구)

  • 노규석;김유일;구정서;송달호
    • Proceedings of the KSR Conference
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    • 1998.05a
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    • pp.369-376
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    • 1998
  • For a good crashworthy design of train vehicles, it is essential to develop some design and analysis techniques for energy absorbing structures. This paper analyzes the front structure of TGV-K and suggests crashworthy design of Korea high speed tram(KHST) using the accident scenario of SNCF(collision with a stationary rigid mass in motion of 15 ton at 110km/h). Specifically this research is concentrated on developing a well-designed protective headstocks using mullticell structures wi th cutouts to improve crashworthiness of KHST

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An experimental study for fire protective coating structure according to Shape factor (철골 단면형상에 따른 내화구조의 실험적 연구)

  • Ok, Chi Yeol;Park, Jin O;Jeon, Soo Min
    • Proceedings of the Korea Institute of Fire Science and Engineering Conference
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    • 2013.11a
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    • pp.153-154
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    • 2013
  • 내화구조로 인정을 받은 국내의 철골조 기둥의 경우 대다수가 H형강에 내화제품을 피복한 구조이다. 본 연구에서는 한국산업표준에서 제시하고 있는 단면형상계수를 기준으로 H형강 인정구조와 다양한 단면의 내화구조의 비교실험을 통해 국내 인정제도를 개선하기 위한 자료로 활용하고자 하였다.

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A Study on Controlling the Effects of the Internal Explosion of the Explosive Disposal Structure (폭발물 처리 구조물의 내부폭발 영향 제어에 관한 연구)

  • 강영철;최정욱
    • Journal of the Korea Institute of Military Science and Technology
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    • v.3 no.2
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    • pp.204-212
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    • 2000
  • The waste ammunitions have been accumulated in excessive amounts these days. This study focused on the problems related to the method of ammunition disposal which leads the explosion inside the enclosure structure and controls the effects of detonation. This study enables us to design a new type of explosive disposal facilities that would fit to our environments. And this study gives us the prototype design of the explosive disposal structure that are explored in this research and will give us a chance to develop a new type structure that have not been devised by Army, and also will be applicable to construct a civilian explosive disposal structure located in airports, harbors, and public facilities.

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The Protective Effect of Mineral Water Against UVB Irradiation (미네랄워터의 피부 장벽 보호 효과 연구)

  • Lee, Sung Hoon;Min, Dae Jin;Na, Yong Joo;Shim, Jongwon;Kwon, Lee Kyoung;Cho, Jun-Cheol;Lee, Hae Kwang
    • Journal of the Society of Cosmetic Scientists of Korea
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    • v.39 no.1
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    • pp.39-46
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    • 2013
  • Bicationic minerals such as calcium and magnesium are known to protect the skin barrier. The principal objective of this study was to evaluate the skin barrier protective effects of mineral water, which is composed of calcium, magnesium, manganese, and fluorine. UVB irradiation induces a destruction of tight junction (TJ) components. The TJ permeability barrier was also disrupted by UVB irradiation. We employed a skin equivalent model to assess the efficacy of mineral water in this regard. Mineral water maintained the structure of the skin equivalents following UVB irradiation. The results of the TJ permeability assay showed that mineral water helped to maintain the TJ permeability barrier after UVB irradiation in skin equivalent model. Mineral water supported the structure of TJ components and restored the occludin protein level in differentiated normal human keratinocytes after UVB irradiation. In conclusion, we found out the protective effect of mineral water against UVB irradiation.

Design of Advanced Weathering Steel with High Corrosion Resistance for Structural Applications

  • Choi, B.K.;Jung, H.G.;Yoo, J.Y.;Kim, K.Y.
    • Corrosion Science and Technology
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    • v.4 no.4
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    • pp.121-129
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    • 2005
  • Basic design concept of the future steel structure requires environmental compatibility and maintenance free capability to minimize economic burdens. Recent trends in alloy design for advanced weathering steel include addition of various alloying elements which can enhance formation of stable and protective rust layer even in polluted urban and/or high $Cl^{-}$ environment. The effects of Ca, Ni, W, and Mo addition on the corrosion property of Ca-modified weathering steel were evaluated through a series of electrochemical tests (pH measurement and electrochemical impedance spectroscopy: EIS) and structural analysis on rust layer formed on the steel surface. Ca-containing inclusions of Ca-Al-Mn-O-S compound are formed if the amount of Ca addition is over 25 ppm. Steels with higher Ca content results in higher pH value for condensed water film formed on the steel surface, however, addition of Ni, W, and Mo does not affect pH value of the thin water film. The steels containing a high amount of Ca, Ni, W and Mo showed a dense and compact rust layer with enhanced amount of ${\alpha}-FeOOH$. Addition of Ni, W and Mo in Ca-modified weathering steel shows anion-selectivity and contributes to lower the permeability of $Cl^{-}$ ions. Effect of each alloying element on the formation of protective rust layer will be discussed in detail with respect to corrosion resistance.