• Journal of the Korean Wood Science and Technology
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• 제36권2호
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• pp.56-62
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• 2008

The surface and edge structure of OSB is defined by surface strand orientation and strand mat thickness variation parallel to the length of the panel using video-microscope. The bending strength of OSB was correlated with surface strand orientation and decreased with increasing the orientation angle in the direction parallel to length of the panel. Average strand mat thickness variation parallel to the length of the panel did not influence the bending strength, but the bonding characteristics among the outermost strands affects the bending strength of OSB. Hankinson formula can be used to predicts the MOE according to strand orientation in the surface of OSB, and more precise strand alignment and reducing thickness variation should be important in the structural performance of OSB panels.

• 한국유체기계학회 논문집
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• 제16권6호
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• pp.12-18
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• 2013

This paper presents the performance characteristics of a centrifugal blower using the design parameters of an impeller blade. Two design variables, the bending length from the blade trailing edge and bending angles of an impeller blade, are introduced to analyze the effects on the blower performance. Three-dimensional Navier-Stokes equations with shear stress transport turbulence model are introduced to analyze the performance and internal flow of the blower. Relatively good agreement between experimental measurements and numerical simulation at the design flow condition is obtained. Throughout present study, it is known that pressure increases as the bending length from the trailing edge and bending angle increase while efficiency decreases. But efficiency is decreased. Detailed flow field inside the centrifugal blower is also analyzed and compared.

• 한국소성가공학회:학술대회논문집
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• 한국소성가공학회 2002년도 춘계학술대회 논문집
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• pp.48-53
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• 2002

Sheet or plate bending is one of the most important industrial metal forming processes. And considerable attention has been focused on gaining a better understanding of many of bending characteristics. One of defaults in bending process is the springback. In this study, the springback characteristics of tailor-welded strips in U-bending process was investigated. Furthermore, not only the relationships between the springback and the process variables such as the geometry of the tools and thickness combination of workpiece but also the heat effect which affects the springback due to welding process was experimentally considered. First, tailor-welded strips are joined by the laser welding process and consisted of two types of thickness combinations of the SCPI sheet, 0.8t${\times}$1.2t and 0.8${\times}$1.6t to investigate the effect of different thickness combination on the springback. Secondly, two different directionally welded strips, one was welded along the centerline of the strip-width and the other was along the centerline of strip-length, were adopted to compare the effects of the location of weld line on the springback. And three punch profile radii of 3, 9, and 15 m were used. Some cases of the experimental results were simulated by using a commercial FEM code, PAM-STAMP to compare the experimental results to the analytical ones.

• 소성∙가공
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• 제12권5호
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• pp.440-448
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• 2003

Sheet or plate bending is one of the most important industrial metal forming processes. Considerable attention has been focused on gaining a better understanding of bending characteristics. One of defaults in bending process is the springback. In this study, the springback characteristics of tailor-welded strips in U-bending process was investigated. Furthermore, effect of the process variables such as the geometry of the tools, thickness combination of workpiece, and welding prcoessing on springback were experimentally clarified. First, tailor-welded strips are joined by the laser welding process and consisted of two types of thickness combinations of the SCPl sheet, $0.8t{\times}1.2t$ and $0.8t{\times}1.6t$ to investigate the effect of different thickness combination on the springback. Secondly, two different directionly welded strips, one was welded along the centerline of the strip-width and the other was along the centerline of strip-length, were adopted to compare the effects of the location of weld line on the springback. Some cases of the experimental results were compared to the results simulated by using a commercial FEM code, PAM-STAMP and the theoretical results using the springback formula as well.

• 한국공작기계학회논문집
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• 제17권4호
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• pp.59-66
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• 2008

This paper has proposed a new parameter to interpret the effects of plastic deformation in bending of strips in cylindrical die and punch. With reference to the parameter, we have provided an insight on the separation between strips and punches, the occurrence of the multi-point bending during the process of deformation, the final shapes of strips, and the springback ratios. Also using the parameter, we have considered the different effects between the bending deformation in the cylindrical die and the bending deformation due to pure bending.

• Journal of the Korean Wood Science and Technology
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• 제27권1호
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• pp.9-17
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• 1999

목재의 강도에 영향을 미치는 인자는 다양하기 때문에 본 연구에서는 국산 참나무 아속 주요수종인 굴참나무, 갈참나무, 졸참나무, 신갈나무, 상수리나무를 대상으로 해부학적 특성과 휨강도와의 관계를 규명하여 참나무 아속의 합리적인 이용방안을 위한 기초자료를 얻었다. 해부학적 특성가운데 휨강도에 가장크게 영향을 미치는 인자는 굴참나무는 $1mm^2$ 당 만재 관공의 수, 갈참나무와 신갈나무는 microfibril 경사각, 졸참나무는 목섬유의 길이, 상수리나무는 단열 방사조직 높이였다.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 2006년도 추계학술대회 논문집 Vol.19
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• pp.26-27
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• 2006

The fundamental mechanical characteristics under tensile and bending deformations of hermetically-sealed reinforced Bi-2223 tape and CTOP processed Bi-2223 tape were examined at 77K. Also, the Tensile strain dependence of the critical current, $I_c$, was obtained at 77K and self-field. The reinforced hermetic tape showed higher tensile strength and a better Tensile strain tolerance than the CTOP processed tape. For bending tests, a rho-shaped sample holder was used giving multiple bending strains. in increasing order. In the same case under bending deformation, the hermetic tape showed a higher bending strain tolerance than the CTOP processed tape. This higher strength of the hermetic tape can be attributed to the thick hardened copper reinforcement layer.

• 한국전자파학회논문지
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• 제22권9호
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• pp.888-896
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• 2011

본 논문에서는 Flexible-PCB에 제작된 안테나를 구부렸을 때의 특성 변화를 살펴보았다. Polyimide로 이루어진 Flexible-PCB는 유전율 3.5, 두께 0.125 mm를 가진다. 제안된 안테나는 Bluetooth 대역을 만족하는 기본적인 장방형 루프 안테나와 입력부에 Inverted-L 형태의 스터브를 추가한 안테나이다. 제안된 두 가지 안테나 모델에 대하여 8가지 조건의 bending 변화를 통해 bending 정도에 따른 입력 정합 특성과 방사 형태를 비교하였다.

• Earthquakes and Structures
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• 제16권6호
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• pp.727-741
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• 2019

A reinforced concrete water tank is a typical functional liquid storage structure and cracks are the greatest threat to the liquid storage structure. Tanks are readily cracked due to seismic activity, thereby leading to the leakage of the stored liquid and a loss of function. In order to study the effect of cracks on liquid storage tanks, self-healing and leakage tests for bending cracks and through cracks in the walls of a reinforced concrete water tank were conducted. Material performance tests were also performed. The self-healing performance of bending cracks in a lentic environment and through cracks in a lotic environment were tested, thereby the self-healing width of bending micro-cracks in the lentic environment in the short term were determined. The through cracks had the capacity for self-healing in the lotic environment was found. The leakage characteristics of the bending cracks and through cracks were tested with the actual water head on the crack. The effects on liquid leakage of the width of bending cracks, the depth of the compression zone, and the acting head were determined. The relationships between the leakage rate and time with the height of the water head were analyzed. Based on the tests, the relationships between the crack characteristics and self-healing as well as the leakage were obtained. Thereby the references for water tank structure design and grading earthquake damage were provided.

• 한국생활과학회지
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• 제11권1호
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• pp.79-93
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• 2002

The purpose of this study was to determine the effect of dynamic characteristics of knitted fabrics on the clothing pressure of foundation. Five knitted fabrics of foundation were selected by different fiber types and blended ratios for the study. The dynamic characteristics of foundation wears made with five different fabrics were measured by KES-FB system method. The results of this study were as follows: 1. The tensile linearity and resilience of f1 were lower than those of other samples. While the tensile resistances of f1, f2 and f4 samples were high, the coefficients of friction of them were low. The bending rigidity and geometric roughness of f5 were higher than the others. 2. The clothing pressure of f3 all-in-one sample was the highest, and followed by f5, f4, f2 and f1, respectively. This result showed that the compression resilience affected on the clothing pressure greatly. 3. In terms of the clothing pressure by posture, the clothing pressure at $90^{\circ}$ bending posture was the highest and followed by that at standing and one-leg-up, respectively. The back part of abdomen was pressured most at $90^{\circ}$ bending posture.