• Steel and Composite Structures
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• 제24권4호
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• pp.467-479
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• 2017

The stud is one of the most frequently used shear connectors which are important to the steel-concrete composite action. The static and fatigue behavior of stud in the steel fiber reinforced concrete (SFRC) were particularly concerned in this study through the push-out tests and analysis. It was for the purpose of investigating and explaining a tendency proposed by the current existing researches that the SFRC may ameliorate the shear connector's mechanical performance, and thus contributing to the corresponding design practice. There were 20 test specimens in the tests and 8 models in the analysis. According to the test and analysis results, the SFRC had an obvious effect of restraining the concrete damage and improving the stud static performance when the compressive strength of the host concrete was relatively low. As to the fatigue aspect, the steel fibers in concrete also tended to improve the stud fatigue life, and the favorable tensile performance of SFRC may be the main reason. But such effect was found to vary with the fatigue load range. Moreover, the static and fatigue test results were compared with several design codes. Particularly, the fatigue life estimation of Eurocode 4 appeared to be less conservative than that of AASHTO, and to have higher safety redundancy than that of JSCE hybrid structure guideline.

• 한국전자파학회논문지
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• 제23권2호
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• pp.177-186
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• 2012

본 논문에서는 프로브 커넥터 핀의 누화 특성이 -30 dB 이하를 만족시키는 핀의 피치 및 길이 파라미터에 대한 설계 기준을 제시하였다. 프로브 커넥터 핀의 누화 특성을 분석하기 위하여 격자 구조로 배열된 프로브커넥터 핀의 인덕턴스 성분과 커패시턴스 성분을 추출하였으며, 접지 핀의 개수가 증가해도 이미 계산된 파라미터들을 이용해서 새로운 커패시턴스 및 인덕턴스 성분들을 쉽게 계산할 수 있음을 보였다. 또한, 신호(signal)핀 주변에 위치한 접지(ground) 핀 개수를 증가시키면서 누화 특성을 향상시키는 알고리즘을 제시하였으며, 특히 접지 핀 개수의 증가가 자기장 결합(inductive coupling)에 의한 누화를 효과적으로 제거시킨다는 것을 보였다. 최종적으로는 주어진 접지 핀 개수 및 형상 하에서 -30 dB 이하의 누화 특성을 만족하는 핀의 피치 및 길이를 결정하는 영역을 도시하였으며, 이는 프로브 커넥터 시스템의 누화 특성 설계 시 유용하게 사용할 수 있을 것으로 사료된다.

• 대한토목학회논문집
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• 제31권1D호
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• pp.65-72
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• 2011

고속도로 분기부 연결로상에서는 연속되는 유출형태가 나타나게 되어, 주행상의 안전성을 고려한 1차, 2차 분류지점 간 적정 이격거리(L)를 확보하는 것은 매우 중요한 사항이다. 본 연구에서는 현행 도로설계 지침에서 제시한 240m라는 동일한 설계기준을 적용하는 대신에, 동 구간에서 운전자에게 필요한 인지반응시간과 차로변경시간을 고려한 적정 이격거리를 산정하는 방식을 제안하였다. 특히 인지반응시간과 관련하여 정지시거 계산에 활용되는 기존의 2.5초와 더불어 기하구조 상의 특성을 고려한 판단시거 계산에 활용되는 보다 긴 인지반응시간을 추가적으로 고려하였다. 더불어 적정 이격거리 산정의 타당성을 확인하기 위해 고속도로 분기점 중 사고가 잦은 네 개의 분기점을 대상으로 교통사고 발생현황을 조사하여, 본 연구에서 검토한 적정 이격거리 산정방법을 적용하여 최소 이격거리를 도출하여 보았다. 연구 결과, 현재의 기준치가 정지시거를 중심으로 할 때는 충분한 최소 이격거리를 제시하고 있지만 판단시거를 중심으로 할 때는 충분하지 못하다는 점을 확인할 수 있었다. 사고가 잦은 현장에서 조사한 차량들의 실제 주행속도가 설계속도와 비교해 월등히 높은 점을 감안한다면, 지침에서 제시하는 것과 같은 획일적인 이격거리의 적용보다는 예상되지 못한 상황을 가정하여 적정 이격거리를 구하게 되는 판단시거를 중심으로 한 이격거리 계산과 설계가 오히려 더 설득력 있을 것으로 사료된다.

• Steel and Composite Structures
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• 제27권3호
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• pp.389-399
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• 2018

A perforated shear connector group is commonly used to transfer shear in steel-concrete composite structures when the traditional shear stud connection is not strong enough. The multi-hole perforated shear connector demonstrates a more complicated behavior than the single connector. The internal force distribution in a specific multi-hole perforated shear connector group has not been thoroughly studied. This study focuses on the load-carrying capacity and shear force distribution of multi-hole perforated shear connectors in steel-concrete composite structures. ANSYS is used to develop a three-dimensional finite element model to simulate the behavior of multi-hole perforated connectors. Material and geometric nonlinearities are considered in the model to identify the failure modes, ultimate strength, and load-slip behavior of the connection. A three-layer model is introduced and a closed-form solution for the shear force distribution is developed to facilitate design calculations. The shear force distribution curve of the multi-hole shear connector is catenary, and the efficiency coefficient must be considered in different limit states.

• 한국공작기계학회논문집
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• 제17권6호
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• pp.118-123
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• 2008

Weakness process can be called ferrule array and epoxy filling process at connector manufacturing process, and a lot of problems happen as think as general manufacturing process at early investment. Wished to improve this and working environment mend of worker on childhood(planning phase) and problem that is happened at done ferrule array and epoxy injection by emphasis target. By ferrule sorting and Improvement of epoxy filling process, bring authoritativeness elevation of product by fraction defective decrease of product by sized work along with productivity elevation. On the other hand, working jigs are various in characteristics of optical connector manufacturing line. There have been lots of restriction in practice because the applicability of this system is only for single type model though the network should be smooth between lines. Thus, it is not only needed the recognition of necessity in industrial line but also the development of automation system arraying ferrule and filling epoxy in the manufacturing process. It is found that the present system development enhances productivity fairly and prevents industrial disaster in the optical connector manufacturing system.

• Structural Engineering and Mechanics
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• 제67권2호
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• pp.131-142
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• 2018

The perfobond connector, composed of a steel plate with a number of holes, serves as a certain type of shear connector in steel and concrete composite structures. Depending on limits in hole distances and rib heights, various hole shapes including circular-hole and long-hole are alternatives for perfobond connectors. This study presented the results of tests performed on 72 push-out specimens with perfobond connectors. The purpose was to evaluate the shear strength of perfobond connectors with circular-hole and long-hole. The effects of various parameters were investigated, including the hole diameter, the hole length, the hole height, the concrete strength, the existence, diameter and strength of rebar in the hole, the thickness, height and distance of perfobond ribs, and the thickness of concrete slabs. On the basis of 132 push-out test results in references and in this study, an analytical model was proposed by regression analysis to predict the shear strength of perfobond connectors. The proposed equation agreed reasonably well with the experimental results of perfobond connectors with different hole shapes.

• Journal of Advanced Marine Engineering and Technology
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• 제24권5호
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• pp.42-51
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• 2000

The performances of the simple expansion, perforated tube, and conical-connector type as an exhaust muffler are shown in this study. Applying a model in which the method of four-pole parameter is used makes theoretical estimation of the insertion loss. Experiment is performed for the measurement of the insertion loss under four cases according to the variation of the tail pipe length. By comparing the theoretical prediction with the experimental results, the validity of the modeling using the method of four-pole parameter is verified. The personal computer simulation programs for the above mentioned theory on the muffler design have been developed and exhaust sound level measurements have been carried out for simple expansion muffler, conical-connector muffler, perforated tube mufflers and the combined type of conical-connector and simple expansion muffler. The measured results for attenuation characteristics of noise for each muffler are compared with the computed theoretical results to verity the confidence and applicable limits of the theoretical equation derived.

• 대한기계학회논문집A
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• 제36권3호
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• pp.347-353
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• 2012

최근 휴대폰은 스마트폰의 출연으로 다기능화가 요구되고 있으며, 각 보드의 전기적 신호를 연결시키는 커넥터는 필수 핵심 부품이 되었다. 커넥터는 많은 양의 전기신호를 처리하기 때문에 소형화, 협피치화가 필요하다. 하지만, 커넥터의 소형화 및 협피치화는 구조적 안전성을 저하시키며, 외부하중에 의한 접촉불량을 발생시킨다. 따라서 본 논문에서는 초소형 협피치 FPC 커넥터를 개발하기 위해 벤치마킹을 통한 초기설계안을 도출하였으며, 터미널 두께 0.2mm, 개수 50 개를 기준으로 하였다. 체결성능을 평가하기 위해 수치해석 모델을 구성하였으며, 다구찌 방법을 이용하여 형상 최적화를 수행하였다. 또한, 터미널의 한계수명을 예측하기 위해 피로해석을 수행하였으며, 체결 성능이 향상된 최종형상을 도출하였다.

• 한국품질경영학회:학술대회논문집
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• 한국품질경영학회 1998년도 The 12th Asia Quality Management Symposium* Total Quality Management for Restoring Competitiveness
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• pp.361-377
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• 1998

The measurement of welding temperature of connector is usually performed with an infra red temperature gauge. However, the factors, which influence the temperature measurement, are rarely known. This research used the welding temperature measurement of the connector as an example, applying the experimental design, in two-phase experiments, to search the affecting factors. In phase-I experiment, we used a resolution III, seven-factor fractional factorial design with two levels for each factor. The result showed that none of the factor was significant in affecting the welding temperature when the type I error ${\alpha}$ was 0.05. Next, we did the phase-II factorial experiment with three factors and each factor had three levels. The experiment showed the experimental time was significant in affecting the temperature measurement when the type I error ${\alpha}$ was 0.05. Further Duncan's multiple range tests on the second experimental data showed that the later the experimental time, the weaker the light intensity could have on the temperature measurement and the average of the highest temperatures was lower. Moreover, the later the experimental time, the smaller was the variance of the temperature measurement and the difference between the averages of the highest and the lowest temperatures was also lower.

• 한국콘크리트학회:학술대회논문집
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• 한국콘크리트학회 2008년도 추계 학술발표회 제20권2호
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• pp.77-80
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• 2008

본 연구에서는 현행 설계기준상의 강관말뚝머리 연결부의 결합방법이 갖고 있는 철근 배근 및 정착길이 확보, 전단키 용접 등의 문제점을 개선하기 위해 퍼포본드 전단연결재(Perforated Rib Shear Connector)를 활용한 강관말뚝머리 보강방법을 고안하고 이에 대한 압발저항성능을 실험적으로 검증하였다. 그 결과 퍼포본드를 활용한 보강방법은 연직하중에 대해 기존 방법을 대체할만한 동등 수준이상의 구조 안전성은 물론 시공성 및 경제성 측면에서도 우수한 성능을 갖는 구조 시스템인 것으로 나타남에 따라 상부구조의 작용하중을 강관말뚝으로 전달하기 위한 효율적인 강관말뚝머리 연결부 보강방법의 하나로 자리매김할 것으로 사료된다.