• 한국물환경학회지
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• 제20권2호
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• pp.163-169
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• 2004

Feasibility of using PE sheet laminated CSP(Corrugated steel pipe) to sewers were tested via corrosion and abrasion tests for PE sheet laminated CSP; 1) corrosion test for PE film and PE coated plate, 2) corrosion test for joint of PE sheet laminated CSP, 3) corrosion test for outside of PE sheet laminated CSP, and 4) abrasion test for inside of PE sheet laminated CSP. The results for the corrosion and abrasion tests are as follows. 1. Results for corrosion tests on PE films and zinc coated steel plates that were coated with PE films show that the surfaces of both PE were not changed compared to those of original PE samples. Furthermore, PE films maintained strong adhesion on the steel plates even though they were exposed to sewage and seawater provided cutting planes of the steel plates were treated with molding. But, results for corrosion tests on the spots that were previously cut off by a knife and a cutting planes of the steel plates were treated without molding show that steel plates have been corroded if they were exposed to sewage and seawater. 2. Results for corrosion tests on joints of PE sheet laminated corrugated steel using sewage show that gathering rust was observed at cutting plane of PE sheet laminated corrugated steel after 180 days, but PE film was not flaked off. However, PE film at cutting plane was flaked off when PE sheet laminated corrugated steel was exposed to seawater. Furthermore, flaking process was severely progressed at lockseam points of which the surfaces were not smooth. 3. Results for laying PE sheet laminated corrugated steel under the ground show that the surface of untouched PE film was almost identical to that of original PE film. However, the spots that were previously cut off by a knife and a cutting plane of PE sheet laminated corrugated steel have flaked off. 4. As a result of abrasion tests conducted with PE sheet laminated corrugated steel and sand, brilliance and thickness of PE was not greatly changed under the severe abrasion conditions. Therefore, the durability of PE sheet laminated corrugated steel for abrasion was determined to be good.

• Steel and Composite Structures
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• 제8권3호
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• pp.231-242
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• 2008

This paper presents results of fire tests on corrugated sheets used as load bearing structure of roofs of industrial buildings. Additional tests of bolted sheet connections to the supporting structure at ambient and elevated temperatures are described. Three connection types were tested and their resistance, stiffness and deformation capacity was evaluated. Finite element simulations of the corrugated sheet based on the experimental observations are briefly described and design models are presented.

• 한국정밀공학회지
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• 제33권3호
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• pp.199-205
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• 2016

A thin sheet of metal with corrugated structures has been utilized in various devices: heat exchangers, separators in fuel cells, and many others. However, it is not easy to fabricate thin corrugated structures using a single-step stamping process due to their geometrical complexity. To solve this problem, firstly, a plate type heat exchanger was redesigned to attain the optimal value of aspect ratio and the optimal shape of corrugated structures for the actual loading conditions. A forming analysis of the corrugated plate was then carried out to determine the process parameters. From this work, the optimal value of aspect ratio was found to be 4.6. In addition, the process parameters of heat exchanger forming were optimized using the optimal value of aspect ratio, and the analytical results were evaluated through experiments. The results obtained indicated good agreements between them.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2010년도 추계학술대회 논문집
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• pp.749-750
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• 2010

• 대한기계학회논문집A
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• 제34권2호
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• pp.219-226
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• 2010

스탬핑 프로세서는 고생산성과 낮은 가격으로 인해 자동차 차제나 항공기 부품, 그리고 전자제품 등 다양한 장치에 널리 이용된다. 최근에 에너지 산업과 연관되어 연료전지 분리판, 열교환기 등에 사용되는 주름구조를 가지는 박판의 응용이 급속히 증가되고 있다. 그러나 복잡한 형상 때문에 주름구조물을 한번의 성형으로 만들기가 매우 어렵다. 따라서 본 연구에서는 다단성형공정을 이용하여 성형성을 향상시키는 방법을 제안하였다. 1 차 박판성형 후 열처리를 통하여 가공경화 부분을 제거하고 다시 성형하는 방법으로 복잡하고 실용성이 높은 박판구조물 제작이 가능하도록 하였다. 본 연구에서는 제안한 방법을 검증하기 위하여 판형 열교환기에 응용이 가능한 두께 $100{\mu}m$를 가지는 박판주름구조를 제작하고 공정변수를 연구하였다.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 봄 학술발표회 논문집
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• pp.499-504
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• 2003

Future bridge decks must have high load-resistance capacity as well as fatigue strength to withstand the increase in traffic loading and the increase in span length between girders due to the decrease in the number of main girders. Steel-concrete composite bridge decks may be proper deck types to satisfy such requirements. To promote the application of composite bridge decks, a rational process to predict and evaluate the fatigue behavior of steel concrete composite bridge deck is required. Various types of steel-concrete composite bridge decks have been developed in many countries. In this study, combining advantages of the existing composite deck types, a new type of composite bridge deck is proposed. An experimental study is performed to examine the fatigue behavior of the proposed composite bridge deck. This composite bridge deck consists of corrugated steel sheet, welded T-beams, stud-type shear connectors and reinforced concrete filler. The fatigue tests are conducted under four-point bending test with three different stress ranges in constant amplitude. The fatigue category of the fillet welding between corrugated steel sheet and the T-beam is evaluated based on the S-N data obtained from the experiment.

• 펄프종이기술
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• 제42권5호
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• pp.31-36
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• 2010

When corrugated board is folded at the severely low humidity condition, crack can occur along the scored (or creased) lines of linerboard. This phenomenon is called as score (or crease) crack. It is mainly resulted from the excessive concentration of stress on the outer layer of linerboard. To overcome score crack, many approaches including the installation of constant temperature and humidity system, displacement of low grade raw material by long and strong fibers, or application of water have been tried. We examined the effect of the weight fraction of top layer in two-ply sheet, freeness of top layer stock and wet pressing on strain and elastic modulus of sheet to prevent score crack. Lower freeness and higher press load increased the density and elastic modulus of sheet. Pressing load over the $50kgf/cm^2$, however, decreased the strain of sheet. The weight fraction of top layer had positive effect on strain as well as elastic modulus without increasing the density of sheet.

• 대한기계학회논문집A
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• 제35권8호
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• pp.933-940
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• 2011

주름구조를 가지는 박판구조물은 비행기, 자동차, 전자제품 등의 다양한 용도의 열교환기로 사용된다. 이러한 주름구조를 가지는 박판구조물의 경우 대량생산을 위하여 박판소성가공 공정으로 제작하게 되는데 꺾임 각을 가지는 주름구조를 형성하는 것은 매우 어렵다. 이 문제를 해결하기 위해 본 연구에서는 정확한 주름구조를 형성하기 위하여 일정한 압력을 박판의 전면에 효과적으로 미칠 수 있도록 새로운 고무성형공정을 제안한다. 본 연구에서 제안한 공정을 검증하기 위하여 우선 유한요소해석을 통해 고무성형공정 변수를 최적화하였다. 그리고 최적화한 고무성형공정을 이용하여 꺾임구조와 미세주름 구조를 가지는 박판을 제작함으로써 본 연구에서 제안한 공정이 목표로 하는 박판의 성형에 효과적인 공정임을 검증하였다.

• 펄프종이기술
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• 제30권1호
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• pp.29-43
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• 1998

This study was to investigate the effect of .compressive load and cyclic humidity(2$0^{\circ}C$, 65% and 90% RH) on the physical and mechanical properties of corrugated board. Corrugated boards in the study were under compressive load and under cyclic humidity, and their properties were compared to those without load. Results were summarized as follows ; 1 Statistically significant correlation was shown between the ring crush of the boards and the compressive strength of cylinder specimen made from the boards. So we could study the compressive behavior of board with cylinder specimen. 2. The boards under the compressive load increased their moisture content and thickness much more than those without load both in constant and in cyclic RH. 3. The compressive and tensile strength of board samples were inversely and closely proportional to the sheet moisture content regardless of their load and humidity history. 4. The moisture content did not show any significant proportionality to the change of burst strength of boards within this experiment. 5. Board reconditioning in standard condition led to the recovery of the strength loss that had occurred under various load and humidity condition. 6. The handsheets prepared from the boards that had experienced compressive load and cyclic humidity, and those with no-load and 65% RH did not show any significant difference in strength properties. No physical damage or load-carrying properties of the wood fiber were observed by the compressive load and cyclic humidity history.

• Steel and Composite Structures
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• 제20권1호
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• pp.147-166
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• 2016

The paper presents comprehensive quasi-static stability analysis results for a real funnel-flow cylindrical steel silo composed of horizontally corrugated sheets strengthened by vertical thin-walled column profiles. Linear buckling and non-linear analyses with geometric and material non-linearity were carried out with a perfect and an imperfect silo by taking into account axisymmetric and non-axisymmetric loads imposed by a bulk solid following Eurocode 1. Finite element simulations were carried out with 3 different numerical models (single column on the elastic foundation, 3D silo model with the equivalent orthotropic shell and full 3D silo model with shell elements). Initial imperfections in the form of a first eigen-mode for different wall loads and from 'in-situ' measurements with horizontal different amplitudes were taken into account. The results were compared with Eurocode 3. Some recommendations for the silo dimensioning were elaborated.