• 복합신소재구조학회 논문집
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• 제2권4호
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• pp.11-18
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• 2011

본 논문에서는 컴퓨터 시뮬레이션을 통해 강재-FRP 합성 교량용 방호울타리의 성능을 분석하였다. FRP는 Surface veil, DB 그리고 Roving 섬유로 구성하였다. FRP의 적층을 고려하기 위해 LS-DYNA에서 제공하는 재료모델 MAT58을 사용하였다. 강관과 FRP의 접촉조건을 고려하기 위해 Spot weld 옵션을 사용하였다. 실차충돌 실무 업무편람에 따라 구조적 강도성능, 탑승자 보호성능 및 충돌 후 차량의 거동에 대한 성능평가를 실시하였다. 강재-FRP 합성 방호 울타리는 성능평가를 만족하였다.

• 한국전기전자재료학회논문지
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• 제32권2호
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• pp.116-121
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• 2019

Hexagonal boron nitride particles (s-hBN) modified with 3-aminopropyl triethoxysilane (APTES) were used for the preparation of silicone composite materials. The microstructure of the composite materials was observed, and the thermal conduction and mechanical characteristics of the composite sheets were studied based on the compositions and microstructures. When a small amount of s-hBN particles was used, the thermal conductivity of the composite improved as a whole, and the tensile strength of the sheet also increased. The thermal conductivity and tensile strength of the composite in which a small amount of carbon fiber was added along with s-hBN were further improved. However, the use of carbon nanotubes with structural characteristics similar to those of carbon fiber resulted in lower thermal conductivity and tensile strength. Elastic silicone composites exhibiting 2.5 W/mK of thermal conductivity and a low hardness are expected to be used as thermally conductive interfacial sheet materials.

• Advances in materials Research
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• 제13권5호
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• pp.335-353
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• 2024

In the present paper, a simple quasi-3D integral higher-order beam theory (HBT) is presented, in which both shear deformation and thickness stretching effects are included for mechanical analysis of advanced composite beams with simply supported boundary conditions, handling mainly bending, buckling, and free vibration problems. The kinematics is based on a novel displacement field which includes the undetermined integral terms and the parabolic function is used in terms of thickness coordinate to represent the effect of transverse shear deformation. The governing equilibrium equations are drawn from the dynamic version of the principle of virtual work; whereas the solution of the problem is obtained by assuming a Navier technique for simply supported advanced composite beams subjected to sinusoidally and uniformly distributed loads. The correctness of the present computational method is checked by comparing the obtained numerical results with quasi-3D solutions found in the literature and with those provided by other shear deformation beam theories. It can be confirmed that the proposed model, which does not involve any shear correction factor, is not only accurate but also simple and useful in solving the static and dynamic response of advanced composite beams.

• Geomechanics and Engineering
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• 제28권1호
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• pp.49-64
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• 2022

In this work, the bending and dynamic behaviors of advanced composite plates resting on variable visco-Pasternak foundations are studied using a simple shear deformation integral plate model. The research is carried out with a view to a three-parameter foundation including the influences of the variable Winkler coefficient, the constant Pasternak coefficient and the damping coefficient of the elastic medium. The present theory uses a displacement field with integral terms instead of derivative terms by including also the shear deformation effect without introducing the shear correction factors. The equations of motion for advanced composite plates are obtained using the Hamilton principle. Analytical solutions for the bending and dynamic analysis are deduced for simply supported plates resting on variable visco-Pasternak foundations. Some numerical results are presented to demonstrate the impact of material index, elastic foundation type, and damping coefficient of the foundation, on the bending and dynamic responses of advanced composite plates.

• 한국전산구조공학회:학술대회논문집
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• 한국전산구조공학회 2001년도 봄 학술발표회 논문집
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• pp.181-188
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• 2001

Due to many advantage of advanced composite material, research on the composite compression member is initiated. In this paper structural characteristics of concrete filled glass fiber reinforced composite tubular member is studied. Through 4-point flexural test with various level of axial force, the performance of composite compression member was analyzed. Also numerical method to find P-M diagram of composite compression member was developed. It is demonstrated that result of numerical method agree well with experimental results.

• 대한금속재료학회지
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• 제50권1호
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• pp.86-91
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• 2012

Ti-6Al-4V extra low interstitial (ELI) alloy has been widely used as an orthopedic implant material because of its excellent biocompatibility, corrosion resistance and mechanical properties. However, V-free titanium alloys such as Ti-6%Al-7%Nb and Ti-5%Al-2.5%Fe have recently been developed because of the toxicity of V. Hydroxyapatite (HA) is used as a coating material on Ti or Ti biomaterials due to its good biocompatibility. However, HA coated on Ti alloy causes a problem for tissue by peeling off during usage. Therefore, such peeling off during long time usage can be suppressed by adding HA in Ti or Ti alloy composites. The aim of this study was to manufacture an ultra fine grained (UFG) Ti-Nb-HA bulk alloy, which is usually difficult to fabricate using melting and casting technology, by rapid sintering process using high energy mechanical milled (HEMM) powder.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2003년도 추계학술대회
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• pp.1684-1689
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• 2003

This paper concerns the analytical modeling and dynamic analysis of advanced cantilevered blade structure implemented by a dual approach based on structural tailoring and viscoelastic materials technology. Whereas structural tailoring uses the directionality properties of advanced composite materials, the passive materials technology exploits the damping capabilities of viscoelastic material(VEM) embedded into the host structure. The structure is modeled as a composite thin-walled beam incorporating a number of nonclassical features such as transverse shear, secondary warping, anisotropy of constituent materials, and rotary inertias. The case of VEM spreaded over the entire span of the structure is considered. The displayed numerical results provide a comprehensive picture of the synergisitic implications of the application of both techniques, namely, the tailoring and damping technology on vibration response of thin-walled beam structure exposed to external time-dependent excitations.

• 한국해양공학회:학술대회논문집
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• 한국해양공학회 2006년 창립20주년기념 정기학술대회 및 국제워크샵
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• pp.5-13
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• 2006

Based on the inventions of continuous ceramic fibers, such as C, SiC, $Al_2O_3$ etc., by polymer precursor driven methods, there have been many efforts to fabricate ceramic continuous fiber reinforced composite materials with metals and ceramics matrices. The main purpose of the R & D efforts has been to produce materials for severe environments, including advanced energy systems, advanced transportation systems. The efforts have been started from the R & D of metal matrix composite materials and now the strong emphasis on ceramic matrix composites R & D can be recognized. This paper provides a brief review about the national efforts to establish advanced composite materials for future industries starting from mid 70s. C/Al and SiC/Al are the typical examples to be applied transportation systems and energy systems. The excellences in specific strength and overall mechanical properties, the excellences in environmental resistance make those materials as potential materials for advanced ocean construction and marine transportation systems. About the recent progress in ceramic fiber reinforced ceramic composites, advanced SiC/SiC composites including NITE-SiC/SiC will be introduced and the present status will be introduced.

• 복합신소재구조학회 논문집
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• 제6권1호
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• pp.45-50
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• 2015

This study performed a finite element crash analysis of support structures made of various composite materials for road facilities. The effects of different material properties of composites for various parameters are studied using the finite element commercial package for this study. In this study, the existing finite element analysis of composite post structures using the LS-DYNA program is further extended to compare dynamic behaviors against car crash of the structures made of various composite materials. The several numerical examples show the comparison of the nonlinear dynamic effects for different materials.

• The Journal of Advanced Prosthodontics
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• 제8권4호
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• pp.267-274
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• 2016

PURPOSE. This study aimed to evaluate the effect of surface treatments on bond strength of indirect composite material (Tescera Indirect Composite System) to monolithic zirconia (inCoris TZI). MATERIALS AND METHODS. Partially stabilized monolithic zirconia blocks were cut into with 2.0 mm thickness. Sintered zirconia specimens were divided into different surface treatment groups: no treatment (control), sandblasting, glaze layer & hydrofluoric acid application, and sandblasting + glaze layer & hydrofluoric acid application. The indirect composite material was applied to the surface of the monolithic zirconia specimens. Shear bond strength value of each specimen was evaluated after thermocycling. The fractured surface of each specimen was examined with a stereomicroscope and a scanning electron microscope to assess the failure types. The data were analyzed using one-way analysis of variance (ANOVA) and Tukey LSD tests (${\alpha}$=.05). RESULTS. Bond strength was significantly lower in untreated specimens than in sandblasted specimens (P<.05). No difference between the glaze layer and hydrofluoric acid application treated groups were observed. However, bond strength for these groups were significantly higher as compared with the other two groups (P<.05). CONCLUSION. Combined use of glaze layer & hydrofluoric acid application and silanization are reliable for strong and durable bonding between indirect composite material and monolithic zirconia.