• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2003년도 가을 학술발표회 논문집
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• pp.453-456
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• 2003

This research is to evaluate the seismic performance of reinforced concrete bridge piers with lap-spliced longitudinal reinforcement steels in the plastic hinge region, and to develop the enhancement scheme of their seismic capacity. Six circular columns of 0.6m diameter and 1.5m height were made with two confinement steel ratios. They were damaged under series of artificial earthquakes that could be compatible in Korean peninsula. Directly after the pseudo-dynamic test, damaged columns were retested under inelastic reversal cyclic loading simultaneously under an axial load, P=$0.1f_{ck}A_{g}$, and residual seismic performance of damaged columns was evaluated. Test results show that RC bridge piers with lap-spliced longitudinal steels behaved with minor damage even under artificial earthquakes with 0.22g PGA, but failed at low ductility subjected to the subsequent quasi-static load test. This failure was due to the debonding of the lap splice. The specimens externally wrapped with composite FRP straps in the potential plastic hinge region showed significant improvement both in flexural strength and displacement ductility.

• 대한의용생체공학회:의공학회지
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• 제5권1호
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• pp.1-4
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• 1984

Balancing left/right cardiac output is essential for the automatic control of total artificial hearts(TAH). A fuzzy logic-based control method is presented. We use left atrial pressure(LAP) and right atrial pressure(RAP) as indicators for left/right balancing. The fuzzy controller has four input variables which are measured LAP and RAP and their gradients. Desired variations in left cardiac output(LCO) and right cardiac output(RCO) are calculated to keep LAP and RAP within the Physiological limits. Computer simulations were performed to adjust fuzzy membership functions for variables and verify this control method. Results from simulations showed that LAP and RAP returned to the physiological limits while AoP and PAP stayed within the physiological limits.

• 한국자동차공학회논문집
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• 제6권5호
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• pp.20-27
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• 1998

According as the member of the automobile body structure have been thinned their thickness and have become high strength, each part of the body structure has been put more severe stress condition. And, because fatigue strength of the spot welded lap joint is influenced by its geometrical and mechanical factors, welding condition and etc., there needs a quantitative and systematic evaluation method for them. In this study, by considering nugget edge of the spot weld part of the IB-type spot welded lap joint under tension-shear load to the ligament crack. fatigue strength of various IB-type spot welded lap joints was estimated with the stress intensity factor(S.I.F.) KIII which is fracture mechanical parameter. We could find that fatigue strength evaluation of the IB-type spot welded lap joints by KIII is more effective than the maximum principal stress ($\sigma$1max) at edge of the spot weld obtained from FEM analysis.

• Advances in concrete construction
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• 제9권1호
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• pp.83-92
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• 2020

The use of spliced reinforcing bars in sustainable concrete members to manage inadequate bars length is a common practical issue which is may be due to some limitations. The lap splicing means two bars overlapped in parallel with specified length called the splice length in order to provide the required bond between the two bars. The bond between sustainable concrete and spliced steel bars is another important issue. The normal strength sustainable concrete specimens of sizes 1700×150×150 mm with tension reinforcement lap spliced were selected according to testing device length limitations. These members were designed to fail in flexure in order to investigate the lap spliced tension bars effect. The selected lap spliced tension bars were of 10 mm size with smooth and deformed surfaces in order to investigate the surface nature accompanied with the splice nature. The sustainable concrete mechanical properties and mix workability were also studied. This study reveals that the effect of number of spliced bars on the response of beams reinforced with smooth bars is found to be more obvious than deformed one. Finite element modeling in three dimensions was carried out for the tested beams using ABAQUS software. A parametric study is carried out using finite elements on considering the following parameters, concrete compressive strength, load type and opening in cross section (hollow section) for weight reduction purposes.The laboratory and numerical results show good agreements in terms of ultimate load and deflection with an average difference of 10% and 15% in ultimate load and deflection respectively.

• Plant Biotechnology Reports
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• 제5권1호
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• pp.45-51
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• 2011

A low acid phosphatase 3 (lap3) mutant was identified and characterized from an Arabidopsis activation-tagged (Weigel) population. The roots of the lap3 plants showed lower acid phosphatase (APase) activity compared to wild-type ones under low-Pi conditions ($10{\mu}M\;Pi$). Plasmid rescue experiments revealed that the activation-tagging vector was inserted into the intergenic region between At4g31540 and At4g31550 in the Arabidopsis genome. The genotypic segregation of the lap3 mutation was tightly linked with the phenotypic segregation of root APase activity in the prgeny of lap3. The transcript level of the At4g31520 (SDA1: SEVERE DEPOLYMERIZATION OF ACTIN 1), located 7.4 kb from the CaMV 35S enhancers in the lap3 mutant, was significantly reduced compared to that in the wild type. It was speculated that cellular actin polymerization may be involved in Pi acquisition in higher plants.

• 접착 및 계면
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• 제7권4호
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• pp.1-9
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• 2006

The single lap joint is the most studied joint in the literature in terms of both theory and practice. It is easy to manufacture and the lap shear strength is a useful value for strength assessment and quality control. Simple design rules exist such as the one present in standard ASTM 1002 or in a recent paper by Adams and Davies. The main factors that have an influence on the lap shear strength are the type of adhesive, i.e. ductile or brittle, the adherend yield strength and the overlap length. The overlap increases the shear strength almost linearly if the adhesive is sufficiently ductile and the adherend does not yield. For substrates that yield, a plateau is reached for a certain value of overlap corresponding to the yielding of the adherend. For intermediate or brittle adhesives, the analysis is more complex and needs further investigation. In order to quantify the influence of the adhesive, the adherend and the overlap on the lap shear strength, the experimental design technique of Taguchi was used. An experimental matrix of 27 tests was designed and each test was repeated three times. The influence of each variable could be assessed as well as the interactions between them using the statistical software Statview. The results show that the most important variable on the lap shear strength is the overlap length followed by the type of adherend.

• 한국건설순환자원학회논문집
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• 제8권2호
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• pp.175-182
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• 2020

철근 부식으로 인한 철근 콘크리트 구조물의 내구성능 저하를 방지하는 방법 중 하나인 에폭시 도막 철근의 사용이 증가하고 있으나, 에폭시 도막으로 인한 콘크리트와 철근의 부착성능 부족으로 정착길이 및 겹침이음길이를 증가시켜야하는 것이 문제가 된다. 이 논문은 에폭시 도막 철근의 부착성능을 개선하여 직접인발시험에서 확인한 기본정착길이의 감소 가능성을 실제 휨부재의 이음길이 산정에 반영할 수 있는지를 확인하기 위하여 수행한 실험연구를 정리한 것이다. 휨부재에서 일반철근과 에폭시 도막 철근의 겹침이음 특성을 비교하기 위하여 철근지름 및 겹침이음길이를 변수로 하여 36개의 시험체로 보-단부 실험을 통해 겹침 이음 성능평가를 하였다. 실험결과에 의하면 현행설계기준에 따라 이음길이에 보정계수 1.2를 사용한 에폭시 도막 철근 부착강도와 일반철근 부착강도를 비교한 결과 파괴 양상, 처짐특성 및 균열폭 등을 고려할 때 현행 설계기준에 따른 보정계수의 필요성을 확인하였다.

• 대한기계학회논문집
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• 제16권4호
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• pp.667-674
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• 1992

본 연구에서는 복합재료의 접착이음에 대한 강도 평가법을 확립하기 위한 기 초연구로써 접착이음의 가장기본적인 형태의 하나인 겹치기 이음(single-lap joint: SLJ)에 대한 응력해석과 정적 및 피로 강도시험을 실시하고, 종래의 강도평가법의 문 제점을 파악.검토하고 정량적이고 통일적인 접착이음의 강도평가법의 확립 및 설계 기 준의 설정에 대한 새로운 방향을 모색 하고저 한다.

• Journal of Welding and Joining
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• 제16권1호
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• pp.52-62
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• 1998

Laser beam welding of zinc-coated steel, especially lap joints, has a problem of zinc vapor produced during welding which has a low vaporization temperature of 906.deg. C. It is lower than the melting temperature of steel (1500.deg. C). The high pressure formed by vaporization of zinc during laser welding splatters the molten pool and creates porosities in weld. During laser lap welds of zinc-coated steel sheets with CW CO$_{2}$ laser the gap size has been analyzed and simulated using a FEM. The simulation has been carried out in the range of gap aetween 0 and 0.16 mm. The vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In vaporized zinc gas has effected to prevent heat from conducting toward the bottom of sheets. In the case of too small gap size, zinc gas has not ejected and existed between two sheets. Therefore heat was difficult to conduct from the upper sheet to lower sheet and the upper sheet could over-melted. In the case of large gap size the zinc gas has been prefectly ejected but only a part of lower sheet has melted. The optimum range of gap size in the lap welds of zinc-coated steel sheets has been calculated to be between 0.08 and 0.12 mm. According to the comparison of experiment, the simulation is proved to be acceptable and applicable to laser lap welds.

• 정보처리학회논문지D
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• 제16D권1호
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• pp.133-138
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• 2009

이 논문에서는 2018 평창 동계올림픽 개최를 위한 사전 준비 및 지역 전략 산업 육성정책의 일환으로 추진 중인 강원도의 u-Sports 사업의 하나로 강원도 용평 스키장에 구축된 무선 구간기록 측정 시스템에 적용된 기술과 그 성과를 소개한다. 기록 측정이 필요한 슬로프 구간의 진입점과 진출점에 각각 레이저 센서를 설치하고 각각의 레이저 센서를 센서 노드와 유선으로 연결하여 스키 선수가 해당 구간에 진입하거나 해당 구간을 빠져나가는 순간 센서 노드는 이를 감지하도록 하였다. 각각의 센서 노드는 또한 모뎀을 통하여 CDMA 망에 연결되어 있어서 망을 통하여 NTP 서버로부터 표준 시간을 수신한다. 센서 노드는 분해능이 높은 내부 타이머를 CDMA 망을 통하여 수신한 표준 시간에 동기를 맞추는 NTP 알고리즘으로 기록 측정에 필요한 최소 10 ms의 분해능을 확보하도록 하였다. 각각의 센서 노드에서 측정된 시간 정보는 CDMA 망을 통하여 중앙 관제 센터에 전송된다. 이 논문에서 소개한 무선 구간 기록 측정 시스템은 고가의 장비를 필요로 하지 않으므로 비용이 저렴하며 이 시스템을 사용하면 기존의 수동 측정 방식을 사용한 경우보다 더 간편하게 중앙 관제 센터에서 구간별 기록 정보를 획득할 수 있다는 장점이 있다.