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모아레 간섭계를 이용한 CBGA 패키지의 비선형 열변형 해석
주진원(Jinwon Joo),한봉태(Bongtae Han),조승민(Seungmin Cho) 대한기계학회 2002 대한기계학회 춘추학술대회 Vol.2002 No.8
Thermo-mechanical behavior of a ceramic ball grid array (CBGA) package assembly are characterized by high sensitive moire interferometry. Moire fringe patterns are recorded and analyzed at various temperatures. Thermal-history dependent analyses of global and local deformations are presented. A significant non-linear global behavior is documented due to stress relaxation at high temperature. Analysis of the solder interconnections reveals that inelastic deformation accumulates at eutectic solder fillets only at high temperatures.
정홍식(Hongsik Chung),주진원(Jinwon Joo) 대한기계학회 2012 대한기계학회 춘추학술대회 Vol.2012 No.11
A traditional capacitive touch panel use in-plane force as an input value. For sensing out-of-plane force, touch panel embedded strain gage has been tried using silver patterned printing technique. In this paper, characteristic test of embedded strain gages were performed for determination of gage factor. A robust steel cantilever beam is designed and used, where the width of the beam is tapered to produce a state of uniform strain along its top and bottom surfaces. Thin glass on which silver pattern is printed was bonded on this steel beam, and measurement of gage factor was carried out.
박용욱(YongWook Park),주진원(JinWon Joo) 대한기계학회 2015 대한기계학회 춘추학술대회 Vol.2015 No.11
Wheel dynamometer measures load of wheel shaft during drive. We analyze structure of wheel dynamometer and proposes better design. Conventional design of Wheel dynamometer include four beam structure owing to decrease of interference error. However, it is unstable in variety of conditions. This paper put forward several shapes or beam type and form of slit, and study it. On the other side, interference errors were minimized by using wheatstone bridge circuit of data on the finite element analysis. Also we’ll use shear strain type gauges and draw graphs of strain contour on many forms of wheel dynamometer they are suitable.
롤투롤 시스템 외팔보 가이드 롤러의 브래킷 최적화 설계
노승완 ( Seungwan Noh ),주진원 ( Jinwon Joo ) 충북대학교 산업과학기술연구소 2023 산업과학기술연구 논문집 Vol.37 No.2
Guide rollers play a crucial role in roll-to-roll manufacturing processes, ensuring stable material movement and accurate positioning. In this paper, finite element analysis was used to optimize the design with the goal of reducing the weight and improving the strength of the bracket to improve the precision of cantilever guide rollers for roll-to-roll systems. In addition, finite element stress analysis and optimization design were performed step by step, and a method of modifying design variables using a combination of methods such as element removal method was used to realize the optimal structure. As a result of the stepwise optimal design performed in this paper, the optimization of cantilever guide roller bracket was achieved, which reduces the maximum effective stress by 18.5% while reducing the mass by 35.8%. Tthe allowable bending ratio of the roller was 82.4% similar to that of Class A, a high-precision grade. This research provides valuable insights into the optimization of cantilever guide roller bracket designs for roll-to-roll systems using finite element analysis. The optimized brackets contribute to improved stability, reduced deflection, and increased efficiency in roll-to-roll manufacturing processes, thereby offering significant potential for various industrial applications.
유한요소 해석과 그림자 모아레 방법을 이용한 쌍안경식 로드셀의 변형 해석
윤경선 ( Kyeongseon Yoon ),주진원 ( Jinwon Joo ) 충북대학교 산업과학기술연구소 2023 산업과학기술연구 논문집 Vol.37 No.1
The binocular load cell is widely used for measuring low-capacity loads due to its advantageous features such as a low profile, easy manufacturing process, and the ability to accurately measure strain at the location where the strain gauge is attached. This paper focuses on the design of the load cell's shape and dimensions using beam theory principles. The bending strain generated by the load cell was analyzed through theoretical, numerical, and experimental methods. Finite element analysis was conducted to evaluate the load cell's performance, and the results were compared to the assumptions made in the beam theory. Actual strain gauges were attached to measure and compare the strain, while displacement was analyzed using the shadow moire technique. The strain analysis results obtained through finite element analysis showed good agreement with the strain measurements from the strain gauges, with a difference of less than 5%. The displacement values measured using the shadow moire technique at the strain gauge location of the binocular load cell aligned well with both the strain analysis values obtained through finite element analysis and the strain measurements.
스트레인 게이지 휘스톤 브리지 회로 출력 측정 비교 연구
최윤희 ( Yunhui Choi ),주진원 ( Jinwon Joo ) 충북대학교 건설기술연구소 2019 建設技術論文集 Vol.38 No.1
스트레인 게이지로 휘스톤 브리지회로를 구성하고, 저항변화에 의해 변화된 휘스톤 브리지 회로의 전압변화율로부터 게이지 상수 값을 이용해 변형률을 결정한다. 브리지 회로를 구성하는 방법은 1/4 브리지(quarter bridge), 1/2 브리지(half bridge), 완전 결선 브리지(full bridge) 가 있다. 본 논문에서는 실험을 통해 1/4 브리지의 출력과 완전결선 브리지의 출력을 비교하였다. 또한 출력 변형률 대신에 출력한 전압을 직접 측정하여 단위변환을 진행한 후의 여러 브리지의 출력을 비교하였다. 완전결선 브리지와 1/4브리지를 이용한 변형률 측정 실험 결과, P3 인디케이터를 이용한 측정 시에는 0.9 μm/m의 차이가 발생하였고, MX440A 인디케이터를 이용한 측정 시에는 0.8 μm/m의 차이가 발생했으며, 이는 완전결선 브리지 결과에 대해 각0.09 %, 0.08 %로 매우 작은 오차가 발생하였다. 또한, 전압 측정 실험 결과 완전결선브리지와 1/4브리지의 결과 값 차이는 P3인디케이터를 이용한 측정 시 0.001 mV/V가 발생하였고, MX440A 인디케이터를 이용한 측정 시 0.013 mV/V의 차이가 발생하였으며, 이는 완전결선 브리지의 변형률 측정 결과에 대해 각 0.04 %, 0.6 %이다. MX440A 인디케이터를 이용한 측정 시 발생하는 차이의 원인을 분석하기 위해 추가 실험을 진행하였다. 추가 실험 결과 하중이 증가할수록 μm/m로 측정한 결과보다 mV/V로 측정한 후 환산한 값이 작게 나왔으며, 변형률에 대해 약 0.5 %의 차이를 보였다. A Wheatstone bridge circuit is constituted by a strain gauge and the strain is determined by using the gauge constant value from the voltage change rate of the Wheatstone bridge circuit changed by the resistance change. The method of constructing the bridge circuit is a quarter bridge, a half bridge, and a full bridge. In this paper, the output of the 1/4 bridge is compared with the output of the full bridge by experiments. In addition, the output voltage was directly measured instead of the output strain, and the outputs of the various bridges after the unit conversion were compared. As a result of the strain measurement using the full bridge and the 1/4 bridge, there was a difference of 0.9 μm/m in the measurement using the P3 indicator and 0.8 μm/m in the measurement using the MX440A indicator, 0.09 % and 0.08 %, respectively, for the complete bridge results. In addition, as a result of the voltage measurement experiment, the difference of the result of full bridge and 1/4 bridge was 0.001 mV/V when measured with P3 indicator and 0.013 mV/V when measured with MX440A indicator, 0.04 % and 0.6 %, respectively, for the strain measurement results of the fully connected bridge. Additional experiments were conducted to analyze the cause of differences in the measurement using the MX440A indicator. As a result of the additional test, the value converted to mV/V was smaller than that measured in μm/m as the load increased, and the difference was about 0.5 % with respect to the strain.