• 한국정보통신학회논문지
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• 제16권7호
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• pp.1455-1462
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• 2012

본 논문에서는 BCD 공정 기반으로 PMIC용 고신뢰성 24비트 듀얼 포트(dual port) eFuse OTP 메모리를 설계하였다. 제안된 dynamic pseudo NMOS 로직회로를 이용한 프로그램 데이터 비교회로는 program-verify-read 모드에서 프로그램 데이터와 read 데이터를 비교하여 PFb(pass fail bar) 핀으로 비교 결과를 출력한다. 그래서 한 개의 PFb 핀만 테스트하므로 eFuse OTP 메모리가 정상적으로 프로그램 되었는지를 확인할 수 있다. 그리고 program-verify-read 모드를 이용하여 프로그램된 eFuse 저항의 변동을 고려한 가변 풀-업 부하(variable pull-up load)를 갖는 센싱 마진 테스트 회로를 설계하였다. Magnachip $0.35{\mu}m$ BCD 공정을 이용하여 설계된 24비트 eFuse OTP 메모리의 레이아웃 면적은 $289.9{\mu}m{\times}163.65{\mu}m$($=0.0475mm^2$)이다.

• 한국공작기계학회논문집
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• 제16권3호
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• pp.125-132
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• 2007

The purpose of present paper is to investigate a fracture characteristics of the finite-width single-edge-notch(SEN) carbon fiber/epoxy reinforced plastics(CFRP) plates by using an acoustic emission(AE). Uni-directionally oriented 10 plies CFRPs specimen which had different notch length were prepared for monotonic tensile test. Matrix cracking appeared over whole testing process and fiber breaking appeared later on mainly Load distribution factor of the matrix confirmed that increased according as increases of plate width ratio. The amplitude distribution of AE signal from a specimens is an aid to the determination of the different fracture mechanism such as matrix cracking, disbonding, interfacial delamination, fiber pull-out, fiber breaking, and etc. In the result of AE amplitude distribution analysis, matrix cracking, fiber disbonding or interfacial delamination, and fiber pull-out or fiber breaking signal correspond to <65dB, <75dB, and <90dB respectively, Also, changes of the slope of cumulative AE energy represented crazing phenomena or degradation of materials.

• International Journal of Aeronautical and Space Sciences
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• 제12권1호
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• pp.84-91
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• 2011

A finite element analysis for the wing and landing gear of a composite target-drone air vehicle was performed. For the wing analysis, two load cases were considered: a 5g symmetric pull-up and a -1.5g symmetric push-over. For the landing gear analysis, a sinking velocity of 1.4 m/s at a 2g level landing condition was taken into account. MSC/NASTRAN and LS-DYNA were utilized for the static and dynamic analyses, respectively. Finite element results were verified by the static test of a prototype wing under a 6g symmetric pull-up condition. The test showed a 17% larger wing tip deflection than the finite element analysis. This difference is believed to come from the material and geometrical imperfections incurred during the manufacturing process.

• 전력전자학회논문지
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• 제5권5호
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• pp.501-507
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• 2000

형광등용 전자식 안정기의 개발에 있어서, 최근 선전류 고조파 성분의 제한에 관한 여러 가지 규제를 만족시키기 위해 역률 개선 회로를 부가하는 것이 권장되고 있다. 본 논문에서는 자려식 전류원 방식 푸시-풀 공진형 인버터의 전력 트랜스포머의 2차측과 별도의 한 개의 커패시터를 사용함으로써 역률 개선을 수동소자로만 이용하여 전류원 방식의 공진형 인버터를 채택하는 형광등용 전자식 안정기를 저가격화, 고역률화하는 것을 목적으로 한다.

• 한국농공학회논문집
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• 제55권3호
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• pp.113-121
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• 2013

Recently, it has been studied for the application of nano-materials in the concrete. Applied a small amount of nano-materials can achieve the goal of high strength, high performance and high durability. The small addition of nano clay improves strength, thermal stability, and durability of concrete because of the excellent dispersion. The present study has investigated the effectiveness, when varying with the contents of nano clay, influencing the pull-out behavior of macro synthetic fibers in nano materials cement mortar. Pullout tests conducted in accordance with the Japan Concrete Institute (JCI) SF-8 standard for fiber-reinforced concrete test methods were used to evaluate the pullout performance of the different nano clay. Nano clay was added to the 0, 1, 2, 3, 4 and 5 % of cement weight. The experimental results demonstrated that the addition of nano clay led to improve the pull-out properties as of the load-displacement curve in the precracked and debonded zone. Also, the compressive strength, flexural strength and pullout performance and of Mix No. 1 and No. 2 increased up to the point when nano clay used increased by 2 and 3 % contents, respectively, but decreased when the exceeded 3 and 4 %, respectively. It was proved by verifying increase of the scratching phenomenon in macro synthetic fiber surface through the microstructure analysis on the surface of macro synthetic fiber.

• 한국지반신소재학회논문집
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• 제19권1호
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• pp.1-9
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• 2020

This paper presents the results of experimental investigation on the effect of degree of saturation of soil on the pullout behavior of a geogrid. Different test variables were taken into account while performing the experiment including the soil physical conditions based on water content and external loading applied. The soil used was locally available weathered granite soil. The tests included variations in saturation of about 90%, 80%, 70% and 45% (optimum moisture content). The pullout tests were performed according to ASTM standard D 6706-01. The results indicate that increasing the degree of saturation in the soil decreases the pull-out capacity, which in turn decreases the interface friction angle and interaction coefficient. The decrease in the pullout interface coefficient was observed to be around 12.50% to 33.33% depending on the normal load and degree of saturation of the soil. The test results demonstrated the detrimental effect of increasing the degree of saturation within the reinforce soil on the pullout behavior of reinforcement, thus on the internal stability. The practical inferences of the outcomes are analyzed in detail.

• Steel and Composite Structures
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• 제33권1호
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• pp.1-18
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• 2019

In the present study, the behavior of steel plate shear walls (SPSW) with variable column flexural stiffness is experimentally and numerically investigated. Altogether six one-bay one-story specimens, three moment resisting frames (MRFs) and three SPSWs, were designed, fabricated and tested. Column flexural stiffness of the first specimen pair (one MRF and one SPSW) corresponded to the value required by the design codes, while for the second and third pair it was reduced by 18% and 36%, respectively. The quasi-static cyclic test result indicate that SPSW with reduced column flexural stiffness have satisfactory performance up to 4% story drift ratio, allow development of the tension field over the entire infill panel, and cause negligible column "pull-in" deformation which indicates that prescribed minimal column flexural stiffness value, according to AISC 341-10, might be conservative. In addition, finite element (FE) pushover simulations using shell elements were developed. Such FE models can predict SPSW cyclic behavior reasonably well and can be used to conduct numerical parametric analyses. It should be mentioned that these FE models were not able to reproduce column "pull-in" deformation indicating the need for further development of FE simulations with cyclic load introduction which will be part of another paper.

• Composites Research
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• 제34권1호
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• pp.30-34
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• 2021

This paper present a three-dimensional unit cell finite element analysis to predict the pull-out behavior of a single stitch in a composite laminate. The stitching process used for this study correspond to the I-fiber stitching method that has been studied by the Composite Structures Lab (CSL) as a new through-thickness reinforced method. A total of six cases were analyzed, which were divided in two groups by the stitching yarn used, 6k and 12k. Each group of cases have three different thickness according to the amount of plies; 16 plies, 32 plies and 64 plies. The finite element analysis used the cohesive zone method to characterize the single stitch reinforcement in the interface. Due to the complexity of the load vs displacement curves taken from the experimental results, a bilinear and trilinear bridging laws were implemented in the models. The cohesive parameters used for each case showed a good agreement with the experimental data and can be used for future studies.

• 재활복지공학회논문지
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• 제9권4호
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• pp.309-317
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• 2015

본 연구에서는 노약자들의 등산활동 시 많이 사용되는 등산스틱의 안전과 성능의 평가를 위한 등산스틱 시험규격 안을 제안하였다. 연관규격조사, 관련 특허 및 논문 조사, 제품현황조사, 파손사례조사, 전문가조사 등을 통해 9가지 등산스틱 성능(안전)요인을 도출하였으며 이 요인들을 시험하기 위한 규격시험장비 3종(비틀림 및 직진도 시험장비, 내구성 시험장비, 스파이크 및 팁 내구성 시험장비)을 설계 제작하였다. 시험에 사용한 시료는 2014년 9월 네이버 쇼핑 기준 판매순위 상위 브랜드 15개의 일자형 손잡이 제품(각 제품별 6개 시료)을 선정하여 사용하였다. 성능요인에 대한 실제시료시험결과 및 전문가회의를 통해 총 6가지의 시험규격 항목 안(편심하중, 길이조절부 압축, 손목걸이 하중, 바스켓 하중, 스파이크 및 팁 내구성, 등산스틱 당김)을 도출하였다.

• 생물환경조절학회지
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• 제4권1호
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• pp.17-24
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• 1995

본 연구는 파이프하우스의 구조적 안전성을 검토하는데 필요한 기초자료를 구축하기 위하여 실시하였다. 지반에 매입된 파이프의 지점상태를 검토하여 적합한 구조해석 모델을 찾고, 파이프를 말뚝기초로 가정했을 때의 파이프의 지지력 및 인발 저항력을 구하기 위하여 모형 실험을 실시하였으며, 그 결과를 요약하면 다음과 같다. 1. 파이프하우스의 지점상태를 검토해본 결과 단동 하우스에서는 수평 및 연직하중 모두 고정으로, 연동하우스에서는 수평하중 재하시 힌지, 연직 하중 재하시 고정으로 해석하는 것이 실험치에 더 가까운 것으로 나타났다. 2. 지반에 매입된 파이프의 인발저항력은 파이프 직경 및 매입깊이에 따라 논의 연한지반에서는 35-54kg, 밭의 보통지반에서는 61-98kg, 단단한 지반에서는 108-120kg이상으로 나타났으며, 파이프와 흙사이의 주변마찰력은 1.51-4.76t/$m^2$정도의 범위를 보였다. 3. 파이프 직경 및 매입깊이에 따른 기초 지지력은 연한지반의 경우 35-76kg, 보통지반은 88-158kg, 단단한 지반은 131-305kg의 범위를 보였으며, 파이프의 선단지지력은 연한지반 0-22kg, 단단한 지반 22-140kg으로 나타났다. 4. 국내에서 많이 보급되어 있는 대표적인 파이프하우스의 경우, 적설심 30cm 까지는 파이프의 매입깊이가 30cm이면 지지력이 충분하지만 그 이상의 적설심에서는 지반의 종류에 따라 매입깊이를 증가시켜야 하고, 인발저항의 경우도 풍속 30㎧까지는 매입깊이 30cm이면 충분하지만 그 이상의 풍속에 대하여는 매입깊이를 증가시키거나 보강이 필요한 것으로 나타났다.