• 한국생산제조학회지
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• 제19권2호
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• pp.260-266
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• 2010

Today's consumers are looking for emotional design which can fulfill their own potential desire. Emotion varies according to individual circumstance, age, sex, culture, education, profession and so on. Automotive instrument panel design is the most important part of interior design, because it affects the impression of interior design and has the equipments for safety, entertainment and various information. Thus, this study was performed to apply emotional design to automotive instrument panel which is the most important part of automotive interior, and find the best bonding conditions to build instrument panel efficiently by comparing mechanical properties in thermoplastic resin of polyethylene (PE) adhesion. Satisfactory adhesion was executed in ultrasonic welding for the same materials of PE. The best welding conditions were found to be welding time of I second, welding pressure of 250 kPA for PE-PE welding. Dissimilar materials were adhered when adhesion and ultrasonic welding were performed at the same time.

• Corrosion Science and Technology
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• 제15권6호
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• pp.314-319
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• 2016

Reduced activation ferritic-martensitic steels (RAFM) are envisaged in future fusion technology as structural material which will be in direct contact with a flowing liquid lead-lithium melt, serving as breeder material. Aluminium-based coatings had proven their ability to protect the structural material from corrosion attack in flowing Pb-15.7Li and to reduce tritium permeation into the coolant, significantly. Coming from scales produced by hot dipping aluminization (HDA), the development of electrochemical-based processes to produce well-defined aluminium-based coatings on RAFM steels gained increased attention in research during the last years. Two different electrochemical processes are described in this paper: The first one, referred to as ECA, is based on the electrodeposition of aluminium from volatile, metal-organic electrolytes. The other process called ECX is based on ionic liquids. All three processes exhibit specific characteristics, for example in the field of processability, control of coating thicknesses (low activation criteria) and heat treatment behavior. The aim of this article is to compare these different coating processes critically, whereby the focus is on the comparison of ECA and ECX processes. New results for ECX will be presented and occurring development needs for the future will be discussed.

• 반도체디스플레이기술학회지
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• 제17권3호
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• pp.75-84
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• 2018

According to IHS, the overall display market is expected to grow at an average annual rate of 6% from $ 104 billion in 2016, to $ 138 billion in 2021. Among them, the OLED display panel will grow from $ 15 billion to $ 41 billion over the same period, forecasting a high annual growth rate of 22%. However, the refraction index, light leakage, bubble generation, adhesion deterioration, peeling phenomenon, moisture resistance, light transmittance, low turbidity. OCA (optically clear adhesive), which solves problems such as improving the resistance of the conductive film, is largely dependent on imported products. In addition, in 2016, the world market is worth KRW4.3 trillion, and the adhesive market has a large market effect. In this study, we tried to analyze the technical competitiveness of patent and thesis by classifying OCA (optically clear adhesive, optical adhesive) for display panel by curing method. As a result of the study, the amount of patents and papers in Korea was found to be superior to other competitors, but the quality level was low. In particular, it was found that the achievements of the papers in the hot melt field are lacking and the government should expand its support.

• 한국염색가공학회지
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• 제34권3호
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• pp.173-184
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• 2022

In this study, the TPU film was laminated on an aramid fabric or circular knits in order to implement an air cushion material that can respond to high impact forces in case of a fall and is easy to expand. To increase the bonding strength between the fabric layer and the film layer, a primer layer was formed in two ways: one for thermally bonding and laminating PET film and two for coating and aging hot melt type PUR adhesive. The tensile strength of the aramid air cushion was 2.5 times higher than that of the circular knits, but the tensile elongation of the aramid air cushion was very low compared to that of the circular knits. The tear strength of the aramid air cushion was about twice or more superior to that of the circular knits, the primer treatment method was good at A, and the peel strength was excellent at method A. The aramid air cushion was the lightest in weight. Summarizing the above results, it was best to combine the air cushion material with aramid woven fabric and primer treatment method A to cope with the high impact force applied when falling.

• Steel and Composite Structures
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• 제44권1호
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• pp.105-117
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• 2022

Impact resistance efficiency of the newly designed sandwich beam with a laterally arched core as bio-inspired by the woodpecker is numerically investigated. The principal components of the beam comprise a dual-core system sandwiched by the top and bottom laminated CFRP skins. Different materials, including hot melt adhesive, high-density polyethylene (HDPE), acrylonitrile butadiene styrene (ABS), epoxy resin (EPON862), aluminum (Al6061), and mild carbon steel (AISI1018), are considered for the side-arched core layer of the beam for impact efficiency assessment. The aluminum honeycomb takes the role of the second core. Contact force, stress, damage formation, and impact energy for beams equipped with different materials are examined. A diversity in performance superiority is noticed in each of these indicators for different core materials. Therefore, for overall performance appraisal, the impact resistance efficiency index, which covers several chief impact performance parameters, of each sandwich beam is computed and compared. The impact resistance efficiency index of the structure equipped with the AISI1018 core is found to be the highest, about 3-10 times greater than other specimens, thus demonstrating its efficacy as the optimal material for the bio-inspired dual-core sandwich beam system.

• Structural Engineering and Mechanics
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• 제85권6호
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• pp.755-764
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• 2023

The article examines the impact response of the sandwich beam furnished by a novel bilayer core as inspired by the woodpecker's head architecture under different repeatedly exerted low-velocity impact loadings by employing the finite element package, ABAQUS. The sandwich beam forms four essential parts comprising bottom and top carbon fiber reinforced polymer laminates encasing bilayer core made of laterally arched solid hot melt adhesive material and aluminum honeycomb. Impact loadings are implemented repeatedly with a steel hemisphere impactor for various impact energies, 7.28 J, 9.74 J, and 12.63 J. Essentially, the commonly concentrated stresses at the impact region are regulated away by the arched core in all considered cases thus reducing the threat of failure. The sandwich beam can resist up to 5 continual impacts at 7.28 J and 9.74 J but only up to 3 times repeated loads at 12.63 J before visible failure is noticed. In the examination of several key impact performance indicators under numerous loading cases, the proposed beam demonstrates favorably up to 1.3-11.2 higher impact resistance efficacies compared to existing designs, therefore displaying an improvement in repeated impact resistance of the new design.

• Elastomers and Composites
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• 제37권4호
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• pp.244-257
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• 2002

주사슬에 나프탈렌고리와 테트라메틸렌 및 헥사메틸렌 유연격자를 가지면서 트라이어드메소겐을 갖는 새로운 열방성 방향족 액정 폴리에스테르(TLCP)를 용액중합법에 의하여 합성하였다. TLCP의 함량을 달리하는 TLCP/PEN in situ 복합재료를 용융방사하여 연신비가 각각 다른 단섬유를 제조하고 그들의 열적, 기계적 특성 및 모폴로지를 조사하였다. 합성된 TLCP는 네마틱 액정중합체였으며 고체상에서 액정상으로의 전이 온도는 249 ℃였다. 블렌드내의 TLCP 도메인들은 매트릭스 고분자인 PEN에 잘 분산 되었으며 어떠한 거대 상 분리 현상도 보여 주지 않았다. TLCP 함량의 증가에 따른 블렌드내 PEN의 cold crystallization 온도가 낮아진 것으로 보아서 TLCP가 PEN에 대한 조핵제 역할을 하였음을 알 수 있었다. 블렌드 섬유내의 TLCP의 도메인 크기는 대략 40 ~ 50 nm정도의 미세한 크기였으며 매트릭스와의 사이에 좋은 계면 접착력을 보였다. 또한 cold 및 hot-drawing 과정을 거친 낮은 draw ratio(DR)에서는 거의 fibril이 형성되지 않았지만, 높은 DR에서는 잘 발달된 fibril들을 보여 주었다. TLCP의 강화효과로 인하여 10 wt% TLCP/ PEN 블렌드 섬유의 초기 모듈러스는 270 %, 인장강도는 235 %의 증가를 보여주었다. 반면에 신장률은 DR의 증가와 함께 감소 하였다.

• Advanced Composite Materials
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• 제18권4호
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• pp.351-364
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• 2009

The thermal stability and elevated temperature mechanical properties of $SiC_P$/Al-11.7Fe-1.3V-1.7Si (Al-11.7Fe-1.3V-1.7Si reinforced with SiC particulates) composites sheets prepared by spray deposition (SD) $\rightarrow$ hot pressing $\rightarrow$ rolling process were investigated. The experimental results showed that the composite possessed high ${\sigma}_b$ (elevated temperature tensile strength), for instance, ${\sigma}_b$ was 315.8 MPa, which was tested at $315^{\circ}C$, meanwhile the figure was 232.6 MPa tested at $400^{\circ}C$, and the elongations were 2.5% and 1.4%, respectively. Furthermore, the composite sheets exhibited excellent thermal stability: the hardness showed no significant decline after annealing at $550^{\circ}C$ for 200 h or at $600^{\circ}C$ for 10 h. The good elevated temperature mechanical properties and excellent thermal stability should mainly be attributed to the formation of spherical ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase particulates in the aluminum matrix. Furthermore, the addition of SiC particles into the alloy is another important factor, which the following properties are responsible for. The resultant Si of the reaction between Al matrix and SiC particles diffused into Al matrix can stabilize ${\alpha}-Al_{12}(Fe,\;V)_3Si$ dispersed phase; in addition, the interface (Si layer) improved the wettability of Al/$SiC_P$, hence, elevated the bonding between them. Furthermore, the fine $Al_4C_3$ phase also strengthened the matrix as a dispersion-strengthened phase. Meanwhile, load is transferred from Al matrix to SiC particles, which increased the cooling rate of the melt droplets and improved the solution strengthening and dispersion strengthening.

• 폴리머
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• 제29권2호
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• pp.166-171
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• 2005

EPDM(ethylene propylene diene monomer)1실리콘 고무 블렌드를 제조하고, 상용화제와 열노화 시간에 따른 물성 변화를 살펴보았다. EPDM과 실리콘 고무(SR)의 조성비는 90/10에서 $10/90\;wt\%$ 사이로 조절하였으며, Brabender사의 Plasticoder를 사용하여 용융 혼합하고, 열프레스로 가교하였다. 가교된 EPDM/SR 블렌드의 모폴로지를 주사전자현미경으로 관찰하였다. 또한, 블렌드를 $100^{\circ}C$에서 24, 48, 96시간 동안 열노화시켜 경도, 인장 강도, 신장률 및 접촉각을 측정하였다. 모폴로지를 조사한 결과 상용화제를 첨가한 블렌드의 분산상의 크기가 감소하였다. 열노화 시간이 증가함에 따라, 블렌드의 경도와 인장 강도는 감소하였으며, 신장률과 접촉각은 증가하였다.

• 폴리머
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• 제26권3호
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• pp.335-343
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• 2002

블렌드 (PET/PETG 70/30 블렌드) 수지는 폴리에틸렌테레프탈레이트 (PET)와 폴리에틸렌테레프탈레이트 글리콜 (PETG)을 무게 비 70/30으로 혼합하여, 이축 압출기를 사용하여 제조하였다. 미연신 필름은 이 블렌드와 순수 PETG 수지를 압축성형기로 각각 용융 압축시켜 제조하였고 연신 필름은 미연신 필름을 모세관 레오메타를 사용하여 연신시켜 제조하였다. 제조된 블렌드 연신 필름과 PETG 연신 필름의 결정성, 수축율, 열적, 동역학적 및 기계적 특성을 X-선 회절분석기, 오븐기, DSC, 및 인장시험기를 사용하여 조사하였다. 블렌드와 PETG필름의 결정화도와 밀도는 연신비와 연신 속도의 증가와 더불어 증가하였으나 반면 연신 온도 증가와 더불어 감소하였다 또한 블렌드 필름의 결정화도와 밀도는 PETG 필름보다 높게 나타났다. 두 필름의 인장강도와 인장탄성률은 연신비 및 연신 속도 증가와 더불어 증가하였고 연신온도 증가에 따라 감소하였다. 또한 블렌드 필름의 인장강도와 인장탄성률이 PETG 필름 보다 높게 나타났다. 두 필름의 수축율은 연신비와 연신 속도가 증가할수록 감소하였고 미연신 블렌드 필름의 수축율이 순수 PET 필름보다 600% 증가함을 보였다.