Fracture Properties of Wide-Notch Concrete Beams strengthened with Near-Surface Mounted CFRP Rebar

Zhenhua Ren,Xiantao Zeng,Junbo Sun,Jun Wang 대한토목학회 2019 KSCE JOURNAL OF CIVIL ENGINEERING Vol.23 No.11

Carbon fiber reinforced polymer (CFRP) is a promising engineering material nowadays. This study carried out four-point-bending fracture experiment on wide-notch-concrete beams reinforced with near-surface mounted (NSM) CFRP rebar, aiming at exploring the effect of CFRP rebar on beam fracture characteristics. The test comprised four groups concrete beam specimens (three for each) with varying reinforcing methodologies. The first group specimens were common concrete beams strengthened by one near-surface mounted CFRP bar, while the second group consisted of common concrete beams strengthened by two near-surface mounted CFRP bars. On the issue of the third group, there were three wide-notch concrete beams strengthened with one near-surface mounted CFRP bar. Lastly, three wide-notch concrete beams strengthened with two near-surface mounted CFRP bars form the group four. The study proposed various equations about the rectangular concrete beams strengthened with near-surface mounted CFRP rebar under tension-shearing condition. For both open cracks and closed cracks, the equations concluded stress intensity factor as well as extending angle in mode I and II crack types. Four-point-bending fracture experiments for wide-notch-concrete beams and numerical simulation experiments were included in this research. This research exhibited expanding direction of wing type crack under effective shearing stress by the superposition model of crack tip stress intensity factor and stress intensity factor. Four-point-bending fracture tests for wide-notch-concrete beams and numerical simulation tests are finished in this research. The tests demonstrate characteristics of crack expanding direction, extending angle, vertical displacement, maximum normal stress, shear strain rate, distribution of plastic zones. Combining the theory and reality, the experimental results were in close agreement with the numerical research.

솔더 인쇄조건 및 외적요소가 인쇄효율에 미치는 영향

하충수,권혁구,Ha, Chung-Soo,Kwon, Hyuk-Ku 한국마이크로전자및패키징학회 2018 마이크로전자 및 패키징학회지 Vol.25 No.1

최근 4차 산업혁명의 조류 하에 표면 실장 분야에서도 Smart Factory 구현을 위한 노력이 활발히 이루어지고 있다. 표면 실장 분야에서도 이러한 변화와 발 맞추어 많은 연구가 진행되고 있으며, 그중 핵심 공정이라 할 수 있는 솔더 인쇄 공정의 최적화에 대한 방법과 인쇄 효율에 영향을 미치는 인쇄 외적 요소에 대한 영향도를 분석하였다. 이 분석에는 설비에서 제공하는 Big Data를 활용하여 통계적 방법으로 접근하였고, 신뢰성 높은 결과와 함께 시뮬레이션을 통해 결과을 예측할 수 있는 가능성을 확인하였다. 이 연구가 실장 분야의 Smart Factory 구현에 조금이나마 기여가 되었으면 하는 바람이다. Under the 4th Industrial Revolution, implementation of Smart Factory in the field of surface mounting is an emerging issue. In the field of surface mounting, many researches are going on in line with these changes. Among them, we analyzed the method of optimizing the solder printing process which is a core process and the influence of the external factors affecting the printing efficiency. In this analysis, the Big Data provided by the SPI Machine was used to approach the statistical method, and the possibility of predicting the result through simulation with reliable results was confirmed. I hope this study contributes a little to the Smart Factory implementation.

입력영상 변환에 의한 CNN 기반의 SMT 부품 결함 분류 방법

김영규,박태형 제어·로봇·시스템학회 2019 제어·로봇·시스템학회 논문지 Vol.25 No.3

Surface Mount Technology (SMT) is a manufacturing process in which components are mounted on the surface of a printed circuit board (PCB). The automatic optical inspection system (AOI) has mainly used the learning-based method for the defect classification of the SMT process, and recently the CNN-based classification method has appeared. However, existing techniques do not consider the area margin of the part, so the classification accuracy decreases. In addition, the classification performance of the CNN classifier is degraded due to the uneven color distribution according to the position of the components. In this paper, we propose a system that can extract the component region and improve the color distribution by the input image transformation. We extract the correct component area through vertical and horizontal projection, and the color improvement enhance the brightness value distribution of the component image through local histogram stretching. By experimental result, we prove the performance of the proposed classification method.

표면실장기술(SMT)의 조립 및 접합 신뢰성에 대한 패드설계의 영향에 관한 연구

박동운,유명현,김학성 한국마이크로전자및패키징학회 2022 마이크로전자 및 패키징학회지 Vol.29 No.3

Recently, with the 4th industrial revolution, the demand for high-density semiconductors for large-capacity data processing is increasing. Researchers are interested in researching the reliability of surface mount technology (SMT). In this study, the effect of PCB pad design on assembly and adhesion reliability of passive component was analyzed using design of experiment (DOE). The DOE method was established using the pad length, width, and distance between pads of the PCB as variables. The assembly defect rate of the passive element after the reflow process was derived according to the misplacement direction of the chip resistor. The shear force between the passive element and the PCB was measured using shear tests. In addition, the shape of the solder according to the pad design was analyzed through cross-sectional analysis. 최근 4차산업혁명으로 대용량 데이터 처리를 위한 고집적 반도체에 대한 수요가 증가하고 있다. 반도체 제품에장착되는 소자들의 크기가 작아 짐에 따라 표면실장기술(SMT)의 신뢰성에 대한 연구가 관심을 받고 있다. 본 연구에서는PCB의 패드 디자인이 수동소자의 조립 및 접합 신뢰성에 미치는 영향을 실험 계획법(design of experiment, DOE) 이용하여 분석하였다. 수동소자를 실장하기 위한 PCB의 패드 길이, 너비 및 두 패드간 거리를 변수로 하여 실험계획법을 수립하였다. 저항칩의 오배치(misplacement) 방향에 따른 수동소자의 톰스톤(tombstone)불량률을 도출하였다. 전단테스트를 통해 수동소자와 PCB 사이의 전단력을 측정하였다. 또한, 단면분석을 통해 패드 디자인에 따른 솔더의 형상을 분석하였다.

SMT 검사기를 위한 불량유형의 자동 분류 방법

이재설(Jae-Seol Lee),박태형(Tae-Hyoung Park) 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.18 No.12

The inspection machine in SMT (Surface Mount Technology) line detects the assembly defects such as missing, misalignment, loosing, or tombstone. We propose a new method to classify the defect types of chip components by processing the image of PCB. Two original images are obtained from horizontal lighting and vertical lighting. The image of the component is divided into two soldering regions and one packaging region. The features are extracted by appling the PCA (Principle Component Analysis) to each region. The MLP (Multilayer Perceptron) and SVM (Support Vector Machine) are then used to classify the defect types by learning. The experimental results are presented to show the usefulness of the proposed method.

SMT 검사기를 위한 불량유형의 자동 분류 방법

이재설,박태형,Lee, Jae-Seol,Park, Tae-Hyoung 제어로봇시스템학회 2015 제어·로봇·시스템학회 논문지 Vol.21 No.10

The inspection machine in SMT (Surface Mount Technology) line detects the assembly defects such as missing, misalignment, loosing, or tombstone. We propose a new method to classify the defect types of chip components by processing the image of PCB. Two original images are obtained from horizontal lighting and vertical lighting. The image of the component is divided into two soldering regions and one packaging region. The features are extracted by appling the PCA (Principle Component Analysis) to each region. The MLP (Multilayer Perceptron) and SVM (Support Vector Machine) are then used to classify the defect types by learning. The experimental results are presented to show the usefulness of the proposed method.

우주급 전장품의 표면실장기술(SMT) 동향

이상택(Sang-Taek Lee),김유광(Yu-Gwang Kim),이도경(Do-Kyung Lee),박응식(Eung-Sik Park) 한국항공우주연구원 2019 항공우주산업기술동향 Vol.17 No.2

우주개발 선진국은 지금까지 다양한 우주개발사업을 수행하고 있다. 이러한 다양한 우주개발은 자국에서 개발하고 제작된 부분품이 있기에 가능하다. 특히 전장품의 국산화는 다양한 국내 기반을 형성하는 시작이 된다. 우리는 지금까지 전자 분야의 산업화에서 많은 발전이 있었지만. 이렇게 조성된 산업 기반을 활용하여 전장품의 국산화를 수행하는데 있어 사업의 성공과 실패라는 위험 부담으로 많은 준비를 하며 기다려야 했다. 하지만 지금은 전장품을 국산화 착수하여 성공적을 개발을 진행하고 있다. 본 논문에서는 국산화 전장품 개발에 매우 중요한 전기전자부품을 PCB 표면에 실장하는 표면실장기술(SMT)의 국내 기술의 현황을 설명하고자 한다. The advanced countries of space development have been carrying out various space development projects. This variety of space development is possible because of the component developed and manufactured in the country. In particular, the localization of Electronics Equipment is the beginning of the formation of various domestic bases. We have made many advances in the industrialization of the electronics sector so far. It was necessary to wait for the preparation of localization of electronic equipment using the industrial base thus created, with a lot of preparations at the risk of success and failure of space project. But now, we have started to develop localized electronics equipment and are developing successfully. This paper describes the current status of the domestic technology of surface mount technology (SMT) for mounting EEE parts on the PCB, which are very important for the development of localized electronic equipment.

SMT 마운터의 동특성 분석

임경화(Kyung-Hwa Rim),정진호(Jin-Ho Jung),범희락(Hee-Rak Beom) 한국소음진동공학회 2011 한국소음진동공학회 학술대회논문집 Vol.2011 No.10

Dynamic characteristic analysis is required in developing SMT mounter system with high installation speed and position precision, because of vibration source occurred by positioning head. This paper presents the method of improving dynamic characteristic of SMT(Surface Mount Technology) mounter with finite element method and modal test. The design direction is that natural frequencies of SMT mounter must be higher than the vibration source. In addition, the effect of input shaping on residual vibration reduction is investigated by simulating the response of a first-order system.

B-spline 표면 근사화 기반의 3차원 솔더 페이스트 검사

이준재(Joon Jae Lee),이병국(Byoung Gook Lee),류재칠(Jaechil Yoo) 한국산업응용수학회 2006 Journal of the Korean Society for Industrial and A Vol.10 No.1-1

최근 고집적화, 고밀도화 되어가는 첨단 디바이스와 섬세한 공정들은 SMT(surface mounting technology)에서의 더욱 까다로운 검사 항목들을 요구하고 있다. 특히, 어셈블리 생산품의 불량의 60% 이상을 차지하는 솔더 프린팅의 검사는 이러한 추세에 대응책으로 3차원적인 검사 방식이 기존의 2차원적인 검사방식을 빠르게 대치해나가고 있다. 따라서 본 논문에서는 SMT 어셈블리 라인에서 PCB(printed circuit board)에 프린팅된 솔더 페이스트에 대한 3차원적인 검사를 자동으로 수행하는 인라인형의 고속 3차원 검사 장비 및 측정 알고리즘을 제안한다. 제안한 방법은 3차원 데이터를 B-스플라인으로 표면을 구성한 다음 이를 기반으로 패드를 추출하고, 검사하는 알고리즘이다. Recently advanced device and sophisticated manufacture process by high-density, high-integration require critical inspection criteria in SMT(surface mounting technologies). Especially for solder paste which come out over 60% of inferior goods of all product, 3-dimensional inspection replaces 2-D inspection as a effectiveness substitute of this trend. Therefore this paper proposes a fast 3-D inspection system and measurement algorithm automatically inspecting 3-D solder paste of PCB in SM???? assembly line. The proposed method generates 3-D surface of data using B-spline algorithm and then extracts to inspect the pad.

Influence of Pad Design on Assembly Reliability of Surface Mounted Devices

Dong-Woon Park,Myeong-Hyeon Yu,Do-Hyung Kim,Dong-Min Jang,Jin-Woo Jang,Seung-Yeong Lee,Hak-Sung Kim 한국정밀공학회 2023 International Journal of Precision Engineering and Vol.10 No.5

During the reflow process in surface mount technology (SMT), a passive component misplaced on a pad would be self-aligned or tombstoned due to a restoring force which is driven by surface tension of molten solder. In this study, the influence of pad design on assembly defect rate was experimentally and analytically investigated using computational fluid dynamics (CFD) simulation. The assembly defect rate of the SMT was experimentally derived from the design of experiments (DOE) considering the pad design and the misplacement of the passive component. The restoring force and moment acting on the chip resistor were calculated using CFD simulation considering the fluidic forces of the molten lead-free solder paste during the reflow process according to the amount of the misplacement and the pad design parameters.