• Science of Emotion and Sensibility
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• v.14 no.1
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• pp.127-136
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• 2011

The objectives of this study were to investigate the effects of color characteristics on tactile sensation / sensibility image of silk fabrics and to provide prediction models for their tactile sensation/sensibility image by both mechanical properties and color characteristics. As results, some of tactile sensation/sensibility terms including 'smooth', 'buoyant', 'thick', 'stiff', 'unique', 'casual', 'rural', and 'modern' seemed to be influenced by color characteristics such as achromatic/chromatic and hue / tone as well as by mechanical properties of silk. Moreover, red or green silk was more strongly felt than gray ones for 'thick' and 'stiff' as well as pale or vivid was. On the other hands, 'Rural' and 'casual' were respectively evaluated more highly for green, pale, or vivid silk. These results imply that color could give an effect on subjective tactile sensation / sensibility. Finally, prediction models for some of tactile sensation / sensibility of silk fabrics by both mechanical properties and color characteristics were established.

• Economic and Environmental Geology
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• v.55 no.1
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• pp.1-17
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• 2022

The mechanical and thermal properties of the rock masses can affect the performance associated with both the isolating and retarding capacities of radioactive materials within the deep geological disposal system for High-Level Radioactive Waste (HLW). In this study, the essential parameters for the site descriptive model (SDM) related to the rock mechanics and thermal properties of the HLW disposal facilities site were reviewed, and the technical background was explored through the cases of the preceding site descriptive models developed by SKB (Swedish Nuclear and Fuel Management Company), Sweden and Posiva, Finland. SKB and Posiva studied parameters essential for the investigation and evaluation of mechanical and thermal properties, and derived a rock mechanics site descriptive model for safety evaluation and construction of the HLW disposal facilities. The rock mechanics SDM includes the results obtained from investigation and evaluation of the strength and deformability of intact rocks, fractures, and fractured rock masses, as well as the geometry of large-scaled deformation zones, the small-scaled fracture network system, thermal properties of rocks, and the in situ stress distribution of the disposal site. In addition, the site descriptive model should provide the sensitivity analysis results for the input parameters, and present the results obtained from evaluation of uncertainty.

• Journal of the Korea Institute of Building Construction
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• v.10 no.2
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• pp.89-96
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• 2010

This study was based on an experiment that examines the manufacture and performance of fiber-reinforced cement composite panels. The conclusions were drawn after testing the mechanical properties and durability characteristics of fiber-reinforced mortar, and the mechanical properties and fire resistance of ECC fire resistant column panels. It was found that the fluidity of CEL fiber was lower than that of PVA and NY fiber. The amount of air increased slightly as the combination of fibers caused the number of fine pores to increase. It was found that the mechanical performance and deformability of high strength concrete could be improved through the confinement effect of ECC fire resistant column panels. Through continuous studies on the manufacturing and field construction methods of fire resistant column panels, a new PC method that eliminates weakness in the existing processes may be developed for skyscrapers.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.26-29
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• 2009

매크로 스케일(macro-scale)에서 구조재료의 거동을 보다 자세히 이해하기 위해서는 구조재료를 구성하고 있는 마이크로 스케일(micro-scale)에서의 미세구조에 대한 이해가 필요하다. 특히 다결정을 가진 다상재료는 상(phase) 분포 상태에 의해 그 특성이 다르기 때문에, 상 분포에 따른 재료의 특성을 이해하는 것이 중요하다. 본 연구에서는 미세구조의 상 분포 특성을 묘사할 수 있는 상관관계 함수를 이용하여 미세구조의 상 분포 상태를 나타내고, 이를 활용한 미세구조 재구성 방법을 사용하여 2상 미세구조에서 특정 미세구조와 유사한 상 분포를 가진 미세구조를 생성하고 그 특성을 비교하였다. 그리고 다양한 상 분포를 가진 미세구조들에 유한요소해석 기법을 적용하여 미세구조의 역학적인 거동을 분석하였다. 이를 통해, 제한된 정보를 이용하여 통계학적으로 유사한 특성을 나타내는 미세구조를 모델링 할 수 있음을 검증하였고, 이러한 미세구조들 간의 역학적 거동은 서로 거의 동일함을 확인하여 미세구조 재구성 기법이 재료의 역학적인 거동을 예측하는데 유용하게 사용될 수 있음을 확인하였다.

• Proceedings of the Korea Concrete Institute Conference
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• 2009.05a
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• pp.429-430
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• 2009

The flexural strength of reinforced concrete members is strongly governed by mechanical properties of reinforcing bars, especially by yield strength, which have many uncertainties. The correct choice of probabilistic models for yield strength of reinforcement is an essential step to assure the safety and reliability of members. In this paper, a probabilistic model of yield strength of reinforcing bars is proposed based on literature and own experimental data.

• Journal of the Korean Society of Clothing and Textiles
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• v.26 no.12
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• pp.1685-1693
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• 2002

다양한 용도로 사용되고 있는 라미네 이 팅 직물은 주로 별도로 제조된 고분자 필름 또는 막을 접착제, 열, 압력 등을 이용하여 기포(基布)와 결합시키는 방법으로 제조되어 진다. 이축연신시킨 Poly(tetrafluoroethylene) (PTFE) sheet는 매우 우수한 높은 투과성을 지니는 다공성 물질이 며, 본 연구에서는 이 막을 나일론 직물에 라미네이팅시킨 투습방수직물을 시료로 사용하여 라미네이팅 후의 역학특성 변화를 분석 하였다. 라미네이팅에 따른 투습방수직물의 물성과 역학특성의 변화에 관하여 살펴본 결과 다음과 같은 결과를 얻었다. 3-layer 라미네이팅 직물(base fabric-PTFE membrane-knitted lining)의 인열강도는 2-layer라미네이팅 직물 (base fabric-PTFE membrane)에 비해 매우 높게 나타났으며, 가공 전 직물과 비교하여 코팅직물에서 나타난 것과 같은 인열강도의 감소는 나타나지 않았다. 직물-PTFE 막 복합체 의 경우, 라미네 이 팅 이 파단강도 및 파단신도 의 증가에 기여 한 것으로 나타났으며 특히 3-layer 라미네이팅 직물의 경우, 신장률이 20%를 넘어서면서 강도가 현저히 증가하였다. 의복을 착용하였을 때 가해질 수 있을 정도의 소변형(small deformation) 하에서의 역학특성 에 있어서는 라미네이팅에 의해 전단특성이 가장 유의한 변화를 나타내었다. 전단강성(G)과 전단 히스테리시스 (2HG,2HG5)모두 증가하였고, primary hand value 중에서는 stiffness 가장 현저한 증가를 나타내었다

• Journal of the Korea Concrete Institute
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• v.22 no.5
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• pp.651-658
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• 2010

Sixteen concrete mixes reinforced with hybrid steel-polybinyl alcohol (PVA) fibers and a control concrete mix with no fiber were tested in order to examine the effect of the micro and macro fibers on the slump and different mechanical properties of concrete. Main variables investigated were length and volume fraction of steel and PVA fibers. The measured mechanical properties of hybrid fiber reinforced concrete were analyzed using the fiber reinforcing index and compared with those recorded from monolithic steel or PVA fiber reinforced concrete. The initial slump of hybrid fiber reinforced concrete decreased with the increase of the aspect ratio and the volume fraction of fibers. In addition, splitting tensile strength, modui of rupture and elasticity, and flexural toughness index of concrete increased with the increase of the fiber reinforcement index. Modulus of rupture and flexural toughness index of hybrid fiber reinforced concrete were higher than those of monolithic fiber reinforced concrete, though the total volume fraction of hybrid fibers was lower than that of monolithic fiber. For enhancing the flexural toughness index of hybrid fiber reinforced concrete, using the steel fiber of 60 mm length was more effective than using the steel fibers combined with 60 mm and 30 mm lengths.

• Journal of the Korean Recycled Construction Resources Institute
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• v.8 no.4
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• pp.528-536
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• 2020

In this study, high strength mortar and normal strength mortar using waste glass sand were evaluated. The main parameters studied were mechanical properties, alkali-silica reaction(ASR) and residual mechanical properties after ASR. As a result of this experiment, it was found that the increase in strength of the mortar has a limitation in improving the slip of the waste glass sand(GS), and rather, it causes a larger ASR. However, the possibility of improving the slip of GS was confirmed by the temporary increase of initial residal compressive and flexural strength of the mortar containing GS after the ASR. Therefore, to improve the slip of GS, the additional research is required, such as modification of the surface of GS and the incorporation of a binder which can increase the strength and makes matrix compact.

• Proceedings of the Computational Structural Engineering Institute Conference
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• 2009.04a
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• pp.239-242
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• 2009

구조물의 표면에 부착된 압전소자(이하 PZT)의 전기역학적 어드미턴스(Electro-mechanical admittance)는 PZT와 구조물의 상호작용에 의해 발생하는 PZT의 압전효과와 유전성(dielectric)이 결합되어 발생되는 신호이다. 고주파수 대역에서 PZT의 전기역학적 어드미턴스는 구조물의 국부손상에 민감하게 반응하는 것으로 알려져 있다. 실험에서 측정된 PZT의 전기역학적 어드미턴스 분석에 널리 쓰이는 Liang 모델은 구조물을 단자유도계로 단순화하여 구조물의 동적특성이 전기역학적 어드미턴스에 미치는 영향을 정확하게 나타내기 어렵다. 유한요소법을 통해 PZT와 구조물의 상호작용을 해석하면 이러한 문제점을 해결할 수 있다. 그러나 고주파 대역에서 정확한 해석을 위해서는 유한요소망을 조밀하게 구성해야 하므로 많은 계산비용이 수반된다. 이 연구에서는 유한요소법과 비교하여 월등히 적은 계산비용으로 고주파 대역의 동적 응답을 매우 정확하게 모사할 수 있는 스펙트럼 요소법(Spectral Element Method ; 이하 SEM)을 통해 판구조물에 부착된 PZT의 전기-역학적 어드미턴스를 해석한다. 수치 예제 및 실험 예제를 통하여 내민보에 부착된 PZT에서 발생하는 전기-역학적 어드미턴스를 취득하고 이를 SEM해석 결과와 비교한다.

• Membrane Journal
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• v.32 no.1
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• pp.57-65
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• 2022

Recently, computer simulation research has been rapidly increasing due to the development of computer and software technology. In particular, various computational simulation results related to polymers, which were previously limited by problems of the number of atoms and model size, are being published. In this study, a study was conducted to analyze the mechanical properties, one of the important properties for using a polymer material as a membrane, using molecular dynamics (MD) simulation. To this end, polyethylene (PE) and polystyrene (PS), which are commercial polymer materials with widely reported related properties, were selected as polymer models and the tensile properties of each polymer were compared through the difference in main chain length. Through the density, radius of gyration, and scattering analysis, it was found that the model produced in this study was in good agreement with the mechanical property trends obtained in the actual experiment. It is expected to enable the prediction of mechanical properties of various polymer materials for membrane fabrication.