• Journal of the Korean Wood Science and Technology
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• 제45권1호
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• pp.28-35
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• 2017

본 연구에서는 접합부가 접착제로 일체화된 강절형 기둥-보 접합 시험편과 슬릿 가공한 보부재에 기둥부재와 일체화된 목질접합물을 삽입하고 핀으로 접합한 시험편을 제작하여 모멘트 저항성능을 검토하였다. 목질접합물은 GFRP로 보강한 적층판을 제작하여 사용하였다. 슬릿 가공된 보부재에 GFRP보강적층판을 삽입하고 핀으로 접합된 기둥-보 시험편들은 완전탄소성 모델 분석으로 산출된 특성치들이 대조군인 강판삽입형 기둥-보 시험편보다 20~80% 낮게 측정 되었다. 기둥부재와 보부재가 접착제로 일체화된 강절형 기둥-보 시험편은 초기잔류변형이 거의 관찰되지 않았으며, 강판 삽입형 접합부보다 38% 향상된 초기강성과 41% 향상된 소성률이 측정되었다.

• 한국복합재료학회:학술대회논문집
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• 한국복합재료학회 2002년도 춘계학술발표대회 논문집
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• pp.215-218
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• 2002

In this paper, we applied composite material of high specific stiffness and strength to the fabrication of a folding wheelchair frame for the replacement of conventional metal wheelchair frames. A one-body composite frame was designed and the finite element analysis was performed on this design. Some specimens of joint parts were manufactured and strength test was done. With the results of analysis and test, some modification was done and a prototype was produced.

• Journal of the Korean Wood Science and Technology
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• 제45권5호
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• pp.535-543
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• 2017

목구조물 기둥-보 접합물로는 슬릿 가공된 부재에 강판을 삽입한 형상이 통용되고 있다. 본 연구에서는 접합부가 접착된 강절형 문형라멘프레임 및 강판 대용인 목질접합물을 제작하여 절반은 기둥부재에 일체화하고 나머지 절반은 보부재와 핀으로 접합한 반강절형 문형라멘프레임을 제작하였다. 목질 문형라멘프레임들은 강판삽입형 접합부 문형라멘프레임과 수평내력성능을 비교 분석하였다. 수평내력성능은 완전탄소성모델 분석과 구간별 강성변화율 및 단기허용전단내력으로 평가하였다. 실험결과, 강절형 문형라멘프레임의 최대내력이 강판삽입형 접합부 문형라멘프레임 보다 낮게 측정되어 항복 내력은 0.58, 종국내력은 0.48로 산출되었으나, 초기강성과 소성률은 각각 1.35, 1.1 향상된 값이 측정되었다. 반강절형 문형라멘프레임의 완전탄소성모델 분석 결과 최대내력은 강절형 문형라멘프레임보다 낮았으나 파괴 후 인성이 우수하여 종국내력은 1.05~1.07 높은 값이 산출되었다. 강판삽입형 문형라멘프레임은 반복 시험이 진행됨에 따라 강성이 급격히 감소한 반면 접합부가 목질로된 문형라멘프레임들의 강성은 서서히 감소되었다.

• 대한기계학회:학술대회논문집
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• 대한기계학회 2008년도 추계학술대회A
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• pp.622-624
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• 2008

This investigation studies the effects of material properties and corresponding propagation wave types on optimal configurations of sound absorbing porous materials in maximizing the absorption performance by topology optimization. The acoustic behavior of porous materials is characterized by their material properties which determine motions of the frame and the air. When the frame has a motion, two types of compressional wave propagate in the porous material. Because each wave in the material make different influence on the absorption performance, it is important to understand the relative contribution of each wave to the sound absorption. The relative contribution of the propagating waves in a porous material is determined by the material properties, therefore, an optimal configuration of a porous material to maximize the absorption performance is apparently affected by the material properties. In fact, virtually different optimal configurations were obtained for absorption coefficient maximization when the topology optimization method developed by the authors was applied to porous materials having different material properties. In this investigation, some preliminary results to explain the findings are presented. Although several factors should be considered, the present investigation is focused on the effects of the material properties and corresponding propagation waves on the optimized configurations.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 1997년도 춘계학술대회논문집
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• pp.257-260
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• 1997

The high precision of the products manufatured by press forming requires the high stiffness of press machines. In this study, the C-frame type press is analyzed to provide the basic idea on the C-frame press design, especially on the frame design. The finite element method is applied for the analysis and the isotropic propertics of the frame material is also considered. The results are summarized in terms of stresses and displacement distributions. Also, the openback angle of the presses is compared with two different models. The CS-150 and ECS-150 models, which are presses model having 150 ton frame capacity relatively and produced by SSangYong precision Co. LTD, are applied for the analysis.

• 한국재료학회지
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• 제20권2호
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• pp.60-64
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• 2010

This study looked at high performance copper-based alloys as LED lead frame materials with higher electrical-conductivity and the maintenance of superior tensile strength. This study investigated the effects on the tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases when Cr was added in Cu-Fe alloy in order to satisfy characteristics for LED Lead Frame material. Strips of the alloys were produced by casting and then properly treated to achieve a thickness of 0.25 mm by hot-rolling, scalping, and cold-rolling; mechanical properties such as tensile strength, hardness and electrical-conductivity were determined and compared. To determine precipitates in alloy that affect hardness and electrical-conductivity, electron microscope testing was also performed. Cr showed the effect of precipitation hardened with a $Cr_3Si$ precipitation phase. As a result of this experiment, appropriate aging temperature and time have been determined and we have developed a copper-based alloy with high tensile strength and electrical-conductivity. This alloy has the possibility for use as a substitution material for the LED Lead Frame of Cu alloy.

• 한국재료학회지
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• 제20권2호
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• pp.65-71
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• 2010

In this study, the effect of Sn and Mg on microstructure and mechanical properties of Cu-Fe-P alloy were investigated by using scanning electron microscope, transmission electron microscope, tensile strength, electrical conductivity, thermal softening, size and distribution of the precipitation phases in order to satisfy characteristic for lead frame material. It was observed that Cu-0.14wt%Fe-0.03wt%P-0.05wt%Si-0.1wt%Zn with Sn and Mg indicates increasing tensile strength compare with PMC90 since Sn restrained the growth of the Fe-P precipitation phase on the matrix. However, the electrical conductivity was decreased by adding addition of Sn and Mg because Sn was dispersed on the matrix and restrained the growth of the Fe-P precipitation. The size of 100 nm $Mg_3P_2$ precipitation phase was observed having lattice parameter $a:12.01{\AA}$ such that [111] zone axis. According to the results of the study, the tensile strength and the electrical conductivity satisfied the requirements of lead frame; so, there is the possibility of application as a substitution material for lead frame of Cu alloy.

• 대한조선학회논문집
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• 제49권3호
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• pp.232-238
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• 2012

The effects of temperature on the structural behavior of polar class vessels have been experimentally and numerically investigated. Experiments were carried out on single frame structures made of steel material, DH36, which is used for outer shell of the vessels making transit through the polar region. A knife edge type striker was dropped down onto single frame structures. The temperatures of the single frames were set to $-30^{\circ}C$, $-50^{\circ}C$ and room temperature. The deflection around the mid-point of the single frame was measured and numerically simulated using finite element model. Strain rate effect on the structural behavior has been investigated and turned out that the strain rate effect can be neglected. From the results of the experiment and numerical analyses, it has been noticed that the permanent deflection at lower temperature was reduced due to a temperature hardening of material as expected.

• 한국재료학회지
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• 제31권8호
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• pp.450-457
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• 2021

From measured thermal conductivity and modeling by simulation, this study suggests that U-factors are highly related to materials used between steel and polymer. The objective and prospective point of this study are to relate the relationship between the U-factor and the thermal conductivity of the materials used. For the characterization, EDX, SEM, a thermal conductive meter, and computer simulation utility are used to analyze the elemental, surface structural properties, and U-factor with a simulation of the used material between steel and polymer. This study set out to divide the curtain wall system that makes up the envelope into an aluminum frame section and entrance frame section and interpret their thermal performance with U-factors. Based on the U-factor thermal analysis results, the target curtain wall system is divided into fix and vent types. The glass is 24 mm double glazing (6 mm common glass +12 mm Argon +6 mm Low E). The same U-factor of 1.45 W/m²·K is applied. The interpretation results show that the U-factor and total U-value of the aluminum frame section are 1.449 and 2.343 W/m²·K, respectively. Meanwhile, those of the entrance frame section are 1.449 and 2.

• EDISON SW 활용 경진대회 논문집
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• 제4회(2015년)
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• pp.207-211
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• 2015

In this paper, 2 kinds of models about bike frame are simulated with static structural analysis. A bike frame with diamond type is compared with another model that Down tube is eliminated from original diamond frame. About both types of models, Property of a material and conditions of restriction & load are the same. This study shows reinforcement effects of a partial frame by adding down tube and impacts generated by applying a load at the frame such as weak points & high stress parts as well as expected deformation. The structural result of this study indicates that the equivalent stress or total deformation decreases by 57.1% or 36.4%, respectively. Also stress concentration sites are leg connecting parts, front/rear wheels fixed region and Max deformation is generated from Seat tube. In conclusion, A Down tube is highly efficient as reinforcement than frame without non down tube. Furthermore, The safety rises in case of reducing top tube thickness and increasing a reinforcement at leg connecting parts or concentration regions.