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벌지 시험을 이용한 다양한 세장비를 가진 전해 동 박막의 기계적 물성 측정
김동일(Dong-Iel Kim),허용학(Yong-Hak Huh),김동진(Dong-Jin Kim),기창두(Chang-Doo Kee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.10
The bulge deformation of electrolytic copper film with various aspect ratios was measured using micro bulge test. Micro bulge testing system was developed to measure bulge deformation in this study. A bulge pressure test system for pressurizing the bulge window of the film and a micro out-of-plane ESPI(Electronic Speckle Pattern Interferometry) system for measuring deflection of the film were included in the testing system developed. To obtain biaxial elastic modulus of copper films with various bulge windows, several unloading steps were introduced during unloading processes. Along the bulge deformation, pressuredeflection and stress-strain curve was determined using the assumption of spherical and cylindrical membrane, respectively. From biaxial elastic modulus, Elastic modulus was used Poisson’s ratio of 0.34 and was determined as 70 ~ 80 ㎬. It was found that the elastic modulus determined from bulge test was identical with that from the micro tensile test.
마이크로 ESPI 기법을 이용한 동 박막의 인장 특성 측정
김동일(Dong Iel Kim),허용학(Yong Hak Huh),기창두(Chang Doo Kee) Korean Society for Precision Engineering 2004 한국정밀공학회지 Vol.21 No.8
Micro-tensile testing system, consisting of a micro tensile loading system and micro-ESPI(Electronic Speckle Pattern Interferometry) system, has been developed for measurement of micro-tensile properties of thin micro-materials. Micro-tensile loading system had a load cell with the maximum capacity of 50N and micro actuator with resolution of 4.5㎚ in stroke. The system was used to apply a tensile load to the micro-sized specimen. During tensile loading, the micro-ESPI system acquired interferometric speckle patterns in the deformed specimen and measured the in-plane tensile strain. The ESPI system consisted of a CCD-camera with a lens and the window-based program developed for this experiment. Using this system, stress-strain curves for 4 kinds of electrolytic copper foil 18□m thick were obtained. From these curves, tensile properties, including the elastic modulus, yielding strength and tensile strength, were determined and also values of the plastic exponent and coefficient based on Ramberg-Osgood relationship were evaluated.
금 박막에서 마이크로 인장 특성에 대한 입자 크기 영향
김동일(Dong-Iel Kim),허용학(Yong-Hak Huh),기창두(Chang-Doo Kee),연순창(Soon-Chang Yeon),김용협(Yong-Hyup Kim) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.5
Micro-tensile tests for Au thin films with three different thicknesses were carried out to investigate the effect of the grain size on tensile properties. Au thin films with the respective thickness of 0.18, 0.5 and 1.0 ㎛ were produced by sputtering and micro-tensile specimens 2 ㎜ long and 200 μ wide were fabricated using micro-machining process. Tensile stress-strain curves, showing elasitc-plastic behavior, were obtained using the strain measurement system, i.e. micro-ESPI system, developed in this study. From these curves, 0.2% yielding strength, tensile strength and elastic modulus, were determined. It was found that these values were dependent on the grain size of the films. Furthermore, in this study, the effect of the width of the specimens was also investigated.
박막의 기계적 물성 측정을 위한 벌지 시험 시스템 개발
김동일(Dong-Iel Kim),허용학(Yong-Hak Huh),김동진(Dong-Jin Kim),기창두(Chang-Doo Kee) 대한기계학회 2007 대한기계학회 춘추학술대회 Vol.2007 No.5
A bulge testing system was developed to measure mechanical properties of thin film materials. A bulge pressure test system for pressurizing the bulge window of the film and a micro out-of-plane ESPI(Electronic Speckle Pattern Interferometric) system for measuring deflection of the film were included in the testing system developed. For the out-of-plane ESPI system, whole field speckle fringe pattern, corresponding to the out-of-plane deflection of the bulged film, was 3-dimensionally visualized using 4-bucket phase shifting algorithm and least square phase unwrapping algorithm. The bulge pressure for loading and unloading was controlled at a constant rate. From the pressure-deflection curve measured by this testing system, ain-plane stress-strain curve could be determined. In this study, elastic modulus of an electrolytic copper film 18 ㎛ was determined. The modulus was calculated from determining the plain-strain biaxial elastic modulus at the respective unloading slopes of the stress-strain curve and for the Poisson's ratio of 0.34.
마이크로 띠-굽힘 시험법을 이용한 박막 재료의 기계적 물성 측정
김동일(Dong-Iel Kim),허용학(Yong-Hak Huh),김동진(Dong-Jin Kim),기창두(Chang-Doo Kee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.6
Mechanical properties for film material, electrolytic copper film, were measured by strip-bending testing system developed in this study. Strip bending tests were carried out by using bend loading system and out-of-plane deflection measurement system. Strip bend loading system was driven by a linear actuator with high resolution of 4.5 ㎚. The out-of-plane deflection during bend loading was measured by an out-of-plane ESPI system, in which 4-buckets phase shifting algorithm was used for quantitative analysis of the interferometric speckle patterns corresponding to the out-of-plane strains in the specimen with load levels. Furthermore, unwrapped phase was obtained by programming with fast Fourier transform to solve the 2π ambiguity of the phase map. Strip bending test was performed with testing speed and deformation step of 50 ㎛/min and 1㎛ step, respectively. Film bend specimens 8 ㎜ long and 1 and 2 ㎜ wide were prepared by the copper foil with 18㎛ thickness. From the bend tests, micro-tensile stress-strain curves were determined and mechanical properties were obtained: elastic modulus, yielding strength and tensile strength were 70~93 ㎬, 240~300 ㎫ and 330~368 ㎫, respectively. These properties were found to be relatively well agreed with those obtained from micro-tensile test.
마이크로 ESPI기법에 의한 면내 변형 측정 민감도 향상
김동일(Dong Iel Kim),허용학(Yong-Hak Huh),기창두(Chang Doo Kee) Korean Society for Precision Engineering 2006 한국정밀공학회지 Vol.23 No.8
Enhancement methods of sensitivity to in-plane strain measurement by micro-ESPI(Electronic Speckle Pattern Interferometry) technique were proposed using TiN and Au thin films. Micro-tensile strain over the micro-tensile specimens, prepared in micro-scale by those films, was measured by micro-tensile loading system and micro-ESPI system developed in this study. The subsequent measurement of in-plane tensile strain in the micro-sized specimens was introduced using the micro-ESPI technique, and the micro-tensile stress-strain curves for these films were determined. To enhance the sensitivity to measurement of in-plane tensile strain, algorithms of the phase estimation by using curve fitting of inter-fringe and the discrete Fourier Transform with object-induced dynamic phase shifting were developed. Using these two algorithms, the micro-tensile strain-stress curves were generated. It is shown that the algorithms for enhancement of the sensitivity suggested in this study make the sensitivity to measurement of the in-plane tensile strain increase.
마이크로 인장 시험과 띠-굽힘 시험에 의한 나노 금 박막의 인장 물성 측정
김동일(Dong Iel Kim),허용학(Yong Hak Huh),김동진(Dong Jin Kim),기창두(Chang Doo Kee) 대한기계학회 2006 대한기계학회 춘추학술대회 Vol.2006 No.11
Micro-mechanical properties of nano Au thin film were evaluated by measuring tensile deformation from micro in-plane ESPI system and micro out-of-plane ESPI system. Micro tensile test for the thin film was carried out using micro in-plane ESPI system and micro-tensile testing system for nano Au thin film, while micro strip-bending test were performed by portable out-of-plane ESPI system and strip-bend testing system. From these test techniques, micro tensile properties were measured and compared. In micro tensile testing system and strip-bend testing system, micro linear actuator with stroke resolution of 4.5㎚ and load-cell with load capacity of 500mN were used, and tensile and bending deformation were measured, applying continuous strain measurement algorithm and strip-bending theory, developed in this study, respectively. Micro tensile stress-strain curves were determined from the respective measurement of deformation and stress. These curves showed that elastic modulus determined from these respective method has a good agreement, but yielding and ultimate tensile strength are a little different.
조동수(Dong Soo Cho),김동일(Dong Iel Kim),신윤덕(Yun De Shen),기창두(Chang Doo Kee) 대한기계학회 2005 대한기계학회 춘추학술대회 Vol.2005 No.11
In this paper, the visual tracking system for a moving target is proposed in the biped robot of which the movement of the camera is irregular. Hexagonal Matching Algorithm is used to measure the changes of size, location, and rotation angle for a moving object from its image frame. Also, for enhancing the efficiency of the tracking, we can adaptively adjust the starting point and the size of search area from the image information obtained. Finally, using Affine Transform and Kalman Filter, the position estimation of the moving target is refined against the swing of the camera. Experiments of the moving target tracking were implemented with 20-DOF biped robot using mono vision sensor to prove the reliability of the proposed method.